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National Council for Research and Development

NEOEV INSTITUTE FOR ARID ZONE RESEARCH

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REPORT FOR YEAR 1971/72

September 1972 CONTENTS

Page

DIVISION OF LIFE SCIENCES

Research in Physiological Genetics 2 Mechanisms of Heat Acclimation 7 Research in Hematology 9 Effect of Hot Environment on Steroid Metabolism 12 Studies in Animal Physiology 20 Studies of Membrane Structure and Permeability 30 Research in Nitrate Reduction in Plants 35 Photophosphorylation and Ion Translocation in Chloroplasts 41 Physiology of Plant Senescence and Mechanises Involved in the Adaptation of Plants to Stress 44 Plant Introduction and Ecology 53 Human Physiological and Psychological Behavior Under Heat Stress 68

PUBLICATIONS AND REPORTS 12

DIVISION OF ENGINEERING SCIENCES 81

Reverse Osmosis 82 Electrodialysis 91 Ion Exchange 94 Applications of Nuclear Radiation 96 Miscellaneous 100

PUBLICATIONS, PATENTS AND REPORTS 101

DIVISION OF CHEMISTRY 104

Organic Chemistry 105 Physical Chemistry 116 Analytical Chemistry 122

PUBLICATIONS, PATENTS AND REPORTS 125

THE LIBRARY 129 DIVISION OF. LIFE SCIENCES

Head : E. Bedrak I. RESEARCH IN PHYSIOLOGICAL GENETICS

1. The Level of Abscisic Acid (ABA) and the Resistance of Stomata and the

Root to Water Flow in Three Mutants of Tomato, flaaaa (fla)3 sitiens (sit), and notabilis (not) M. Tal and Y. Nevo (Negev university)

The question of whether the three mutations, which are located in three different loci, control the level of ABA and consequently the water balance in the plant was investigated. In all three mutants the level of ABA, free or glucosid-bound, was low as compared with the normal control plants. It was also found that root resistance to water flow is higher in the three mutants than in the control plants. All three mutants reverted phenotypically, including root and stomatal resistances, to the normal type when treated with ABA during development.

2. The Causes of the Low Level of ABA in flaaoa (flc) a Mutant of Tomato Y. Nevo and M. Tal

The reasons for the low level of ABA in fio were investigated and found to be either an inhibition in the biosynthetic pathway of the hormone or enhanced degradation of the hormone in the mutant. 14 The biosynthesis of ABA from CO, as well as the kinetics of degradation cf labeled (H ) ABA are compared in mutant and normal control plants. Ho final results are available.

3. The Influence of ABA on the Biosyntheais of Indoleacetic Acid (IAA) in flaaaa (flo) a Mutant of Tomato A. Erez (Volcani Institute) and M. Tal

It was found that tryptophane transaminaae activity, which is th* first branching enzyme in the biosynthetic pathway of IAA, is higher in flo than in the normal plant. This activity decreased toward the normal level in ABA-treated flo plants. In addition, the production of IAA in vitro was highest in a reaction system extracted from fie, intermediate in ABA- treated flo, and lowest in the normal plant.

4. Comparison of Peroxidase Activity and Content of Hydroxyproline in the Cell Wall Proteins of the Three Tomato Mutants Flaooa, Sitiens and Notabilis and of Normal, Control Plants

M. Tal

The object of this work is to clarify the reason for the difference in extensibility of guard cell walls in mutant and normal plants. The mutant stoiaata remain open in the dark, even when the guard cells are plasraolyzed.

The amino acid hydroxyproline content per unit wall protein is one of the factors which determines extensibility of the cell wall. According to preliminary findings the level of hydroxyproline per unit wall protein is lower in the three mutants than in the normal plants. In addition, a higher peroxidase activity, at least of the soluble fraction, was found in the mutants. Ridge and Osborne (1971) found that hydroxyproline-rich proteins of the cell wall contain peroxidase activity. There are preliminary indications that hydroxyproline content and peroxidase activity are in reverse proportion to the normal levels in ABA-treated mutants.

5. The Effect of ABA on Stomatal Opening or Closure by Influencing the Extensibility of the Guard Cell Wall

M. Tal and X. Gardi (Negev University)

The tomato mutant Flaoaa is used as a special tool to demonstrate the possibility that cytokinins and ABA control stomatal behavior, at least partly» by influencing guard cell wall extensibility. The work takes advantage of the fact that the rautánt stomata remain open even under plaemolysis, i.e., when turgor pressure is practically zero. The basic assumption is that any change in the aperture of plasmolyzed stomata treated with a hormone is related to the effect of the hormone on the extensibility of the guard cell wall. First indications are that ABA induces stomatal closure even in plasmolyzed stomata.

6. The Effect of Different Doses of the Mutation Notcibilie (not) and Poly- ploidy on the Hormonal and Water Balance in the Plant I. Gardi (Negev university) and M. Tal

In many cases the distribution and adaptation of polyploid plants are more successful than that of their diploid relatives. The physiological reasons for this relative success of polyploids are unknown, We are studying, therefore, the effect of different doses of the mutation not, which control the level of ABA and consequently the water balance in the plant, and different ploidy levels on the hormonal and water balance in the plant.

Diploid and tetraploid mutant and normal plants are now ready. Haploid plants will be prepared by pollen grain culture, and triploids by crossing diploid with tetraploids.

7. Improvement of Salt Tolerance in the Cultivated Tomato by Genes Transferred from Salt Tolerant Wild Relatives H. Tal

Wild species of tomato have been found to be more salt tolerant than the cultivated species. In the current work the physiology of salt tolerance in both the cultivated and the more tolerant wild species L. pexmvianum is under investigation. Future work will include transfer of specific genes which control the level of ABA in the plant, from wild species adapted to arid and/or saline conditions to the cultivated species. The work will be extended to other cultivated plants in order to create a pool of genes for salt tolerance in the cultivated species. This pool will be a source of important genetic material for arid-saline areas. 8. Genetic Control of Stomatal Behaviour in the Tomato Mutant» Flaooa

0. Inter

The hypothesis was tested that guard cells of the mutant flacoa are distinguished from those of iie normal plant by higher osmotic pressure which causes them to remain in turgor and keep the stomata open, even under closing conditions. No difference in osmotic pressure between the two could be detected by the plasmolytic methods using isolated epidermis strips.

Recently/ a considerable amount of evidence has suggested the importance of the potassium pump for operating the stomatal mechanism. Accord- ingly the possibility that the mutant guard cells eccumuTate potassium selec- tively was examined.

Using the histochemical method in which cobalt-nitrite-stain is applied, it was found that the mutant stomata behave similarly to the normal stomata in regard to localization of the potassium?specific staid. Under light, whim causes the stomata to open, guard cells were stained while subsidiary cells were not. Under closing conditions, e.g., darkness or ABA application even in light which closes mutant stomata, the guard cells were unstained while the subsidiary cells were stained. Hence, there is a normal potassium shuttle between the guard cells and the subsidiary cells. The passage is quit* fast»- and could be detected as early as 15 minutes after a change in the light regime.

These results refute the above hypothesis. An alternative hypothesis, suggested by N. Tal, that the mutant cell wall was altered and inhibits stomatal closure, finds support in the potassium staining tests. This method causes the stoaata of the, normal plant to close even if they were open before the staining. However, many of the mutant stomata remain open after the staining which indicates a physical change in the cell wall. The ultra- structure of the cell wall of the mutant is currently being studied by electron-microscopy. , In addition, in order to investigate membrane permeability which apparently is altered in the mutant, the uptake of chloride and sodium by leaf discs and isolated roots is being studied in salt depleted plants. While chloride uptake is higher in the mutant than in the normal plant, the situation is reversed in respect to sodium uptake. The effect of ABA on ion uptake in the mutant is also being studied. IX. MECHANISMS OF HEAT ACCLIMATION

1. Effect of Heat Acclimation on the Respiratory Activity of Brown Fat in Hamsters

T. Rabi and V. Cassuto

Findings in our previous works indicated a decrease in the metabolic rate of brown fat in heat-acclimated hamsters. Heat acclimation resulted in a decrease in the total protein content of the brown fat and particularly in the mitochondrial protein content, as veil as a decrease in the third seg- ment of the electron transport chain. These changes were accompanied by a decrease in the oxidation activity in those mitochondria. In the current study the expression of these changes in the respiratory activity of the whole cell was investigated since it is on the level of the whole cell that the thermogenic capacity of the tissue will be determined.

Oxygen consumption of tissue slices was measured with succinate and a-glycero-phosphate which are known as good substrates for the respiratory activity of the tissue. For both substrates, we found that the optimal concentration was much higher than that mentioned in the literature for other tissues as well as for brown fat. The concentration eventually chosen was close to saturation. h decrease in the oxygen uemsuffiptíóñ in the heat- acclimated hamsters was observed for both substrates, as expected. The decrease was 50 percent for succinate and 45 percent for a-glycero-phosphate. Kinetic Properties of Succinate Oxidation by Liver and Brown Fat Mitochondria T. Rabi, Y. Cassuto and A. Livne

As expected from its physiological role in thermogenesis, brown fat displays high respiratory potential. When compared to the well-known oxidative activities of liver mitochondria, the brown fat mitochondria show much higher oxidative activities with several substrates (абР, ascorbate). This is in accord with the higher content of respiratory chain components (at least six-fold higher in brown fat mitochondria than in liver mitochondria) . As brown fat mitochondria esáiibit oxidative activity (with succinate as substrate) similar to that found in liver, we explored the oxidative potentials of liver and brown fat mitochondria. Freezing and thawing as well as sonic oscillation caused a 4-5 fold increase of oxidative activity in brown fat mitochondria, while treated liver mitochondria showed, on protein basis, only a 50% increase. The decrease in the values for succinate oxidation due to freezing and thawing was similar for the mitochondria of the two organs. However, the increase in V due to the treatment was much greater in brown fat ХПаЭС than in liver mitochondria. Thus, in addition to the increased permeability of the treated mitochondria to the substrate, the kinetic properties suggest the activation of succinate dehydrogenase as the mechanism for the marked stimulation of succinate oxidation in brown fat mitochondria. III. RESEARCH IN HEMATOLOGY

1. Seasonal Changes in the Human Erythrocyte N. Meyerstein

The existence of seasonal hematological changes in man is still in doubt. Some reports indicate that climatic changes do not effect changes in red cell count, hematocrit and hemoglobin values. Acute heat stress induces increased osmotic fragility as do experimental pyrexia and in vivo heating. Chronic exposure of hamsters to heat causes an increase in osmotic fragility, and decreases ATP content in the red cells. It does not, however, change red cell count, hematocrit and hemoglobin values.

The effect of the hot, dry Negev climate on human red blood cells was investigated. The subjects were 26 healthy young men from the Negev Institute, selected as a sample of persons working in an air-conditioned environment, and students selected as a sample of persons continuously exposed to a hot environment. Blood specimens were taken in mid-winter and again in mid-summer. The red cell parameters investigated included red cell counts and osmotic fragility, as well as metabolic characteristics such as ATP level, glucose uptake, and lactate production.

No seasonal changes were found in red-cell counts. However, in those, subjects who were exposed to a hot climate, increased metabolism was demonstrated with no deterioration in important parameters such as level and osmotic stability.

This study was supported partly by Grant No. BDPEC-OH-ISR-7, 0 .S. De- partment of Health, Education and Welfare, and partly by the National Council for Research and Development, Israel. 10

2. Effect of Controlled Heat Acclimation on Human Erythrocytes N. Meyerstein

Increased glucose uptake and lactate production were previously demonstrated in seasonally heat-exposed students. In the current study heat acclimation is controlled in the laboratory, and changes in the erythrocytes are investigated. Each subject serves as his own control, by comparison of his pre-acclimation blood with his poet-acclimation sample.

The metabolism of the erythrocytes (glucose uptake and lactate production), osmotic fragility, and ATP level, is being measured. The measurements are made on blood samples taken from each subject both before and after acclimation in dry heat. Whe age distribution of che erythrocyte is checked by reticulocyte counts and D.D.C. The work is in an advanced stage.

3. Oxygen Dissociation Curve in Erythrocytes of Heat Acclimated Hamsters N. Meyerstein and Y. C&ssuto

In previous work done at the Negev Institute it was found that oxygen uptake is decreased in heat acclimated hamsters in the organism generally, in liver slices and in isolated liver-mitochondria. It has also beet shown previously that the levels of ATP and ÖPG decrease in the erythrocyte after heat acclimation is reached. Such a decrease may augment the oxygen affinity of the hemoglobin and decrease oxygen release in >he tissues. .---.,-.--_------.--

Oxygen dissociation curves were checked in the hemclysat» of erythrocytes of both control and heat-acclimated hamsters. The test was performed at 38°C, which is the body temperature of the hamsters. No difference was found between the dissociation curves of control «tnd heat-acclimated groups. It therefore stems that the reduction in oxygen consumption is not expressed at the level of oxygen transport to the tissues. 11

4. Potassium,bevels in Hamster Erythrocytes and Plasma in Heat Acclimation N. Meyerstein

A decrease in the potassium level in erythrocytes' was demonstrated in humans exposed to 46°C ambient temperature, together with a question- able increase in the potassium level in the plasma. In a previous investigation, increased osmotic fragility as well as changes in lipid composition of the membrane were found in erythrocytes of heat-acclimated hamsters. Such findings may indicate potassium leakage from the erythrocyte into the plasma in heat-acclim*ted hamsters. Potassium levels are being checked now in plasma and erythrocytes of both heat-acclimated and control hamsters.

5. Effect of Aldosterone on Hamster Erythrocytes N. Meyerstein

It is often stated that there is hyperaldosteronism in heat acclimation, it' was therefore of interest to see whether injection of a hamster in the control group-with exogenic aldosterone would cause the same changes in the erythrocytes produced by heat acclimation in hamsters.

Osmotic fragility and ATP levels in the erythrocytes were checked several hours after aldosterone injection. The same parameters were measured after prolonged administration of aldosterone (several weeks). It was found that exogenous aldosterone cannot imitate those changes produced by heat acclimation in hamster erythrocytes. 12

IV. EFFECT OF HOT ENVIRONMENT ON STEROID METABOLISM

1. The Relative Roles of the 5-ene and 4-ene Pathways in the Biosynthesis of Testosterone in the Аортщв Cdhirinue Testis

Б. Bedrak and V. Samoiloff

The development of desert areas by man, and the consequent introduction of farm animals to the arid zones (where daytime temperatures are relatively high during most of the year), requires an understanding of the physiological processes which enable mammals to grow and reproduce under the extreme environmental conditions. For this study we selected one of the most common desert rodents found in the northern part of the Hegev Desert—Ааощ-s Cahirinvs.

Previous work demonstrated that the activity of 173-hydroxysteroid oxidoreductase was relatively low in desert rodents, since in their natural habitat they breed only during a limited season and litter size is generally small, it was thought that the lower breeding capacity of the male was correlated with the low activity of the enzyme systems participating in testosterone biosynthesis.

The capacity of Aeomys to synthesize testosterone was evaluated from experiments where various radioactive substrates were incubated with testicular homogenate. The accumulation of 5-ane-3$-hydroxy metabolites suggested that the 4-ene route is the preferred biosynthetic pathway for testosterone. This was confirmed by the simultaneous incubation of {TO 5-ene-3$-hydroxysteroids and < C) 4-ene-3-oxosteroids where the molar ratio of each substrate was determined in the metabolites produced.

Under these experimental conditions the predominant rout* for testosterone synthesis appears to be pregnenolone •*• progesterone -*• 17a hydroxyprogesturon* •*• androstenedions •*• testosterone. 13

The accumulation of 17a20a-dihydroxy-4-pregnen-3-one (a steroid which is not readily metabolized to androgens) suggested that 20a-hydroxysteroid oxidoreductase was as active as 17,20 lyase. Under these circumstances less substrate will be available for the production of testosterone.

Moreover, in comparison with other rodents, Acomys testes were found to have a low 173-hydroxysteroid oxidoreductase activity. This work has been summarized and published.

2. Some Effects of Acclimatization to a Hot Environment on Enzyme Activity of Rat Testes E. Bedrak, V. Samoiloff, U.A. Sod Moriah and S. Goldberg (Negev Central Hospital)

The adverse effect of increased temperature (higher than that existing in the scrotum) on testicular function has been demonstrated with cryptorchid animals. Whether similar effects are also evoked when animals are exposed to elevated ambient temperatures such as those prevailing in hot desert areas during the summer months has not been demonstrated. To answer this question male rats were acclimatized to a hot environment by two procedures: daily 4-hour exposure to a high ambient temperature for 4 weeks or continuous maintenance at 35°C. Although the degree of acclimatization, as determined by the decrease in oxygen uptake and increased excretion of 17 ketosteroids in the urine, was relatively similar in both groups, the intermittent exposure appeared to be the preferred procedure since it did not inhibit growth rate and was free of mortality. The relative activities of enzymes participating in the biosynthesis of testosteron* via the 4-ene route were evaluated from experiments 14

in which radioactive substrate, incubated with testicular homogenate, was transformed to various metabolites. Acclimatized animals showed an increase in activity of 17a-hydroxylase, 20ot-hydroxysteroid oxidoreductase and 17,20 lyase, whereas the activity of 17(J-hydroxysteroid oxidoreductase decreased. Histological examination of the testes revealed that neither the germinal epithelium nor the leydig cells were adversely affected by the increased environmental temperature. Sperm cells collected from the epididymus were motile and appeared to be normal. It seems, therefore, that acclimatization of rats to heat for 4 weeks does not adversely affect the functional activities of the testis. On the other hand, the enzymatic studies suggest that the level of testosterone produced by acclimatized rats might be lower than that of controls (22°C). The first stage of the work has been published and the research project is continuing. Other parameters of testicular function are being investigated in rats acclimatized to a hot environment for longer periods (3-4 months).

3. The Effect of Heat Acclimatization on the Pathway of Androgen Bio- synthesis in Mouse Testes A. Slonim and E. Bedrak

Enzymatic activity was determined by incubation of testicular homo- geaates with labeled substrates and by identifying the various metabolites which were obtained. It was found that the activity of 17-hydroxy steroid dehydrogenase in 11-snonth-old heat acclimatized mice was twice as large as the activity in control mice. By contrast, in young (3 month) animals the mzyme activity in the control mice was 1.5 times greater than in the heat acclimatized animals. As in the case of rats, the activity of 20 steroid oxidoreductase was anhanced by acclimatisation to a hot environment. 15

4. Blood and Tissue Content of C-21 Steroids in Heat Acclimatized Animals J.P.M. Finberg (Negev Central Hospital), E. Bedrak, and Ü.A. Sod-Moriah

Studies on biosynthesis and blood concentration of testosterone in heat acclimatized rats have shown that although marked changes can be detected in the rate of testosterone synthesis in vitro by the A5 and Дц pathways/ the blood testosterone concentration, as determined by gas- liquid chromatography, is only slightly decreased.

The present work will investigate the circulating concentration of progesterone in female rats exposed to heat in relation to the known im- pairment of reproductive performance of these animals. Of particular interest is the drop in progesterone concentration at term with respect to the longer gestational period in the heat acclimatized animals. For this purpose the assay of progesterone by the competitive-protein binding technique is being developed, and the specificity and accuracy of the system investigated. The simplicity and rapidity of this technique will permit the determination of a large number of samples from other heat acclimatized species as well as of human clinical material.

5. Effect of Exposure to Heat on Renin Secretion in Man

J.P.H. Finberg (Negev Central Hospital), G.M. Berlyne (Negev Central Hospital) and E. Bedrak

The secretion of renin by the kidney is known to be increased by re- ductions in extracellular fluid volume; as well as by a fall in body sodium content. The object of this project is to investigate changes in renin secretion upon heat exposure, with respect to changes in extracellular fluid volume and possibly total exchangeable sodium. The effect of »cut* heat exposure in non heat-acclimatized and acclimatized subjects is being investigated. 16

Preliminary results show a marked rise in plasma renin concentration on exposure to dry heat (50°C) and moist heat (37°C wearing an impermeable rubber suit) accompanied by a certain amount of physical exercise in non heat-acclimatized subjects. Further work will be required to define the precise stimulus of renin secretion in such a situation. Changes occurring in heat-acclimatized subjects will be of particular interest since acclimatization is known to be accompanied by marked changes in sweat rate and electrolyte composition.

6. Effect of Ingestión of Brackish Water on Young Bats

G.M. Berlyne (Negev Central Hospital) and E. Bedrak

The reservoirs of brackish water in the Aravah are the main source of water for mammals living in this area. The possibility that ingestión of large amounts of salts would impair the health of mammals was investigated in a preliminary study in which weanling rats were employed. The preliminary work disclosed smaller parathyroid glands accompanied by lower serum calcium in rats OK brackish water.

In the present study young male rats were kept for 5-24 weeks in temperate and hot environments, drinking distilled or brackish water. Their growth rate, parathyroid size and level of calcium, magnesium and.phosphorous in blood, bone and muscle were determined. No adverse effect on growth rate, parathyroid size and mineral content of blood plasma, bone or muscle were found in young and sexually mature rats ingesting brackish Water. These data confirmed other findings made in our laboratory, that high environmental temperature (35°C) leads to a poor growth rate which accounts for the poorer organ and glandular weights of animals maintained in a hot environment. 17

7. Some Parameters of Testicular Function in Heat Acclimatized Male Rats

Ü.A. Sod-Moriah, E. Bedrak and G.M. Goldberg (Negev Central Hospital)

The purpose of the experiments reported here and in the following sections was to study the effect of prolonged exposure to 35°C on intrascrotal (testicular) temperature, on testicular protein synthesis and on mating and reproduction.

Intrascrotal temperature in heat acclimatized male rats exposed to 35°C was found to be 1-1.5°C higher than those of the scrotums of control animals maintained at 22"C. Thus the testes of heat acclimatized males experienced a temperature similar to that in which cryptorchid testes exist. As in the case of cryptorchid testes, the rate of in vitro 14 protein synthesis (studied by the incorporation of L-Lysine-U-C ) is higher, and it is optimal at 36°C as compared to 32°c in control testes.

However, in contrast to the situation in the cryptorchid testes, the "heat-acclimatized" testes continue with spermatogenesis. The animals mate and are capable of siring viable litters, though to a lesser extent than control males. In histological examinations it was noticed that in several foci groups of seminiferous tubules in the testes of heat acclimatized males necrobiosis occurs with some increase in interstitial Lsydig cells, which resembles the picture seen in the cryptorchid testes.

Concomitantly with the experiments on the testes of animals continuously exposed to 35°C we studied the situation in testes of males acclimatized to a hot environment by 4 hours daily exposure to 35°C. Pre- vious studies have shown these males to be heat acclimatized. In this study these males were compared to control males. Thus, again with respect to reproduction, this latter method seems to be preferable for heat-acclimatization of males.

It seems that the adverse effect of heat may be aggravated by increased duration of exposure of 35°C. It is planned to repeat the breeding part of these experiments with males exposed to 35°C for 6-12 months.

The results described here were summarized and submitted for publication. 18

8. Reciprocal Blaatocyst Transfer Between Heat Acclimatized and Control Female Rats U.A. Sod-Moriah and E. Bedrak

The reciprocal egg transfer technique was employed in order to find out whether heat adversely affects the embryo per se or acts by affecting the maternal tissues.

One hundred 5-day-old blastocysts from heat acclimatized animals and sixty-two from control animals were reciprocally transferred from the respective pregnant donors into uteri of heat acclimatized (35°C) and control (22°C) synchronously pseudopregnant recipients. Only partial results were obtained, but it was indicated that the origin of the embryo was of no consequence. As long as the embryos were transferred into uteri of heat acclimatized recipients» survival of the embryo and implantation rates were much lower than in those transferred into control uteri.

Xt seems therefore that the adverse effect of heat on embryo survival is due to its effect on the maternal tissues.

9. Duration of Pseudopregnancy in Heat Acclimatized Female Rats as an Indicator of Function of Corpus Luieum

U.A. Sod-Moriah and Б. Bedrak

In previous investigations it was noted that some of the adverse effects of heat on the reproductive processes of the heat acclimatised female rat could be accounted for by hyperfunction of the corpue luteum or delay in luteolysis.

Evidence supporting this hypothesis was obtained by investigating the duration of pseudopregnancy in rats. In two groups of 25 female rats it was found that while pseudopregnancy lasted 11.4 ± 0.32 days in control animals it lastad 14.0 ± 0.4 day* in heat acclimatized rats

10. Variations in Birth Rate in the Negev Region as Affected by the Environmental Temperature Ü.A. Sod-Moriah and E. BedraK

This study, conducted in collaboration with the physicians of the Negev Central Hospital, is in progress. Data a- - being collected and prepared for computerized statistical analysis.

11. Hyperthermia in Heat-Adapted Female Rats

Ü.A. Sod-Moriah and R. Yagil

The series of experiments which were started last year have been completed. The results indicate that upon exposure to 35°C, deep body temperature of both control and heat acclimatized female rats was 1-1.5 С higher than that of either group at 22°C.

Within 30 minutes of changing the environmental temperature deep body temperature also changed. It seems; therefore, that there was no adaptation to the hot environment as far as deep body temperature is concerned. Opon exposure to a 28°C environment the deep body temperature of both groups (heat- adapted and control animals) was similar. When the two groups of animals were exposed to the extreme temperature of 5°C, both showed an initial drop in body temperature but the drop in the heat-adapted group was greater than of the controls and the heat adapted-animals had difficulty in raising their temperature to normal level. Control animals were able to increase their heat production, raising and maintaining their body temperature readily. Thus, upon exposure to extremely low temperature the heat-adaptation of the animals, achieved by lowering the metabolic rate, is expressed as the difficulty encountered when heat production becomes necessary.

This work was summarized, written up and submitted for publication. 20

V. STUDIES IN ANIMAL PHYSIOLOGY

1. Factors Influencing Milk Secretion in the Rat

И. Morag, R. Yagil and F. Poplicker

An effective bioassay, developed in this laboratory, has enabled the level of milk yield of lactating rats to be established. Experiments on the effect of different climates, of the number of suckling pups, of level of nutrition and of certain drugs on milk yield and on characteristics of mammary tissue have been carried out. Work is continuing.

2. Post partum Fertility of bactating Dairy. Eves

M. Morag in cooperation with E. Eyal and Y. Folman of Volcani Institute

Field work en the possibility of two lambings a year in intensively kept dairy flocks (reported last year) has been estended to a number of farms and the effect of repeated rebreeding in the poet partum period is being examined. Data for a model capable of predicting reproductive and lactational performance are being collected. Physiological, genetic and management factors which affect the reproductive performance during the puerperium are being examined in an experimental flock. Hormonal treat- ' ments, different breeds and levels of nutrition have been tested as to their effect on the fertility of lactating ewes. Work is continuing.

3. Poet partum Fertility of bactating Mutton Ewes

M. Morag in cooperation with R. Wassmuth and K.H. Finger of Giessen University

An experiment was carried out with SchwarisrKopf (SF) and Finn X SF mutton ewes. Lactating sheep were fed rations of either 80% or 120% of standard. ' Milk yield (determined by lamb growth and by a weekly test mi Iking) was increased by the higher level of food intake1. Reproductive activity was not affected and the anoestrous of the SF could not be broken by the additional food. Work is continuing. 21

4. bong Milking Intervals in Dairy Cows

H. Morag in cooperation with K.H. Finger and F. Feldmann of Giessen University

There is interest all over the world in relieving dairy men from milking for one day a week. The reasons for this are both social and religious. The problems predicted in a system based on a milking interval of 24 to 26 hours imposed once a week are i) loss of milk and changes in milk composition, ii) a fall in lactational persistency, iii) the development of udder disease* and iv) pain to the cow. An experiment was carried out in which long milking intervals of up to 48 hours were imposed at weekly intervals in German Friesian cows. Animals which prior to the long intervals were uninfected with mastitis remained clean of udder disease during the experiment. Further* же the level of infection in teats with mastitis was not increased by the long intervals. The effect on milk yield and composition and on urine metabolites is being analysed.

5. Genetic and Environmental Effects on the Ability of Sheep to Withstand Dehydration

M. Morag in cooperation with K.H. Finger and F. Feldmann of Giessen University

Ewes of Finn, Merino and Awassi origin were held in a climatic chamber for two-week periods under simulated desert, arctic and contin- ental climates. At the end of each period water was withheld for 48 hours. The effects of the various environmental conditions on the breeds' blood and urine compositions and on their thermoregulation are being analysed. 22

6. Milking Practice in the Dairy Goat

M. Morag in cooperation with R. Barnea of the Ministry of Agriculture

Work reported last year has continued and secretion rates of milk and milk components and the level of residual milk in milking intervals of between 4 and 24 hours have been established. Species differentiations in lactational physiology as compared with sheep and goats have been described.

7. Models of Animal Production in the Desert

M. Morag and E. Rubin

A theoretical study of potential animal production systems suitable for arid and semi-arid zones is being prepared.

8. A New International Scientific Journal

M. Morag

A proposal for a new scientific journal devoted to the biology of the mammary gland and of milk secretion was accepted by the Amsterdam scientific publishing house Swets & Zeitlinger. An editorial board including senior lactational scientists from all over the world has been formed. Final preparations for a call for papers are under way.

9. The Blood Volume and Life Cycle of the Camel's Erythrocyte

R. Yagil, N. Meyerstein and U.A. Sod-Moriah

To examine whether the camel's ability to preserve water is reflected by a longer life-cycle of its erythrocytes we injected labeled erythrocytes into an eleven-year-old female camel (Camelus Dromedariue) weighing 600 kg. Blood was withdrawn from her jugular vein, and mixed with ACD solution to which 300 ]xc Na2Cr C>4 had been added. After incubation the reaction was halted with ascorbic acid and 35 ml of the labeled blood was injected into the camel. 23

Blood volume was determined from a sample withdrawn 45 minutes after the injections, and the plasma volume was calculated. Daily blood samples were taken and the- haemoglobin content, haematocrit and radioactivity were examined. Corrections were made for PCV and drop in standard. The dis- appearance of Cr from the blood was plotted. The half-life of the erythrccytes (50% drop in radioactivity) appears at 11 days, and extinction (no more radioactive chrome in the blood) was reached after 3 months.

This experiment was carried out in summer, and we are now comparing these data to those obtained during the winter. Further experiments are being carried out while the camel is dehydrated. This means one week without water, water ad libitum for one hour and then a further week without water etc. etc. This will be continued until all the radioactive chrome disappears from the blood.

10. Reabsorption of Sodium in the Puctules of the bactating Breast

R. Yagil, Z. Etzion and G.M. Berlyne (Negev Central Hospital)

It is accepted that the milk-ductules transporting the milk to the nipple are merely conveying tubes. However, as the breast is a modified sweat gland, it seemed probable that the ductular epithelium would modify milk when suitably stimulated.

To examine this hypothesis we used adult female rats in the second week of lactation. The rats were milked by manual expression, and this milk was used as control-milk for the group and for each individual rat. The rats were then injected with aldosterone and a few days later with 9a fluorohydrocortisorie. Both these substances have a known effect on urine secretion, and we wanted to see how milk secretion would be affected.

The milk was analysed for sodium and potassium concentration* using an auto-analyser flam* photometer with interval lithium standard. 24

When compared to control-milk, per group or individual rat there is a statistical significance in the reduction of sodium and Na/K for both aldosterone and 9a fluorohydrocortisone. To see whether .the effect of aldosterone was a specific one on a sodium absorption mechanism in the breast, rats were first miUced without any hormones being injected. This was used as control milk for each animal. Then the rats were milked after administration of aldosterone. After a few days control milk was again removed and then aldosterone and aldactone were injected. This aldactone is a specific antagonist of aldosterone. The results show a highly significant drop in milk sodium and Na/K after aldosterone was injected while the combined injection of aldosterone and aldactone had no effect on the milk sodium or Na/K. This is irrefutable evidence of a sodium reabsorbing mechanism in the rat mammary gland.

11. The Effect of Changing Salinities on the Camel's Erythrocytes R. Yagil, N. Meyerstein and U.A. Sod-Moriah

Our hypothesis is that one of the main factors in the camel's {Camalua DrormdartUB) ability to withstand water deprivation for long periods is the. ability of the erythrocyte to withstand dehydration, that is, a higher hyper- tonicity. The camel's ability to drink great amounts, 50 liters and more within 5 minutes after dehydration, would also depend on the erythrocytes not undergoing haemolysis, that is, a lower hypotonicity.

To test this hypothesis we examined camel erythrocytes in vitro. Our subject was an eleven-year-old female bedouin camel. Blood was withdrawn from the jugular vein and then placed into saline solutions of various concentrations. The blood was examined and photographed under the microscope and it was observed that from the physiological solution of 0.9 percent Nad the solutions that were hypotonic did not affect the erythrocytes until 0.2 percent NaCl, when haemolysis was observed. In hypertonic saline solutions it was noted that as the solutions became more and more hypertonic the erythrocytes appeared to swell and their form changed from oval to round. 25

In 4 percent NaCl solutions, the saline concentration found in sea- water, there is no effect to be seen on the erythrocytes. This would explain in part the camel's ability to drink sea-water. In 10 percent NaCl solutions, some cells seem to have changed shape but no definite crenation can be noted. In 20 percent saline solutions, the majority of the cells seem to have lost their oval shape, but still no typical crenation can be seen. The experiment was repeated to substantiate our results. We are now examining the effects of dehydration and rapid rehydration and high ambient temperatures on the camel's erythrocyte.

12. Acid-Base State of Rat Milk H. Lerner, R. Yagil and G.M. Berlyne (Negev Central Hospital)

No previous work has been found discussing the acid-base equilibrium of rat milk. For this experiment adult female rats in their second week of lactation were used. The milk was obtained by manual expression into capillary tubes which were immediately sealed. The pH and pCX>2 were determined in a glass capillary electrode and pCO- electrode respectively, using a BmS3 astrup apparatus. The bicarbonate concentration was calculated using the Benderson-Hasselbach equation. Strong evidence that rats' milk is an intracellulár secretion was obtained. Further experiments were carried out to examine the effects of ammoniu chloride on acute metabolic acidosis; sodium bicarbonate on acute metabolic alkalosis; niamox Na-acetosolamide on metabolic acidosis; CO_ chamber on respiratory acidosis; and radioactive DMO sulphate and tritium as measures of intracellulár pH. 26

13. Aluminium Metabolism in the Draemic Rat

G. Weinberger (Negev Central Hospital), R. Yagil, F. Pcplicker and G.M. Berlyne (Negev Central Hospital)

Aluminium is an element widely used in medicine, from anti-indigestion tablets to aluminium-cycle resins which lower potassium blood levels in cases of renal failure. It has been universally accepted that aluminium is a harmless element, with no ill effects in the body. To examine the aluminium metabolism in acute renal failure we performed partial nephrectomy on white adult laboratory rats, leaving only 1/3 kidney functional. After the operation the animals were divided into two groups; one group on normal tap water, the other getting 2 percent aluminium sulphate and chloride in their drinking water. The rats drinking tap water remained healthy for as long as they were maintained on tap water. The other group showed stress within a short period of time. They stopped drinking, developed tremors, were totally emaciated, and excreted a red fluid from their eyes. They all died within four days.

Liver, heart, lungs and bones (femurs) were examined for aluminium content. All the organs, and particularly the bones, showed higher levels of aluminium than those found in the animals maintained on tap water.

In a study of humans it was found that patients with renal failure treated with aluminium salts have 100 X more aluminium in plasma than that found in patients not having aluminium treatment. The aluminium clearance per 100 ml G.F.R. was variable and no relationship was found to the inulin Clearance, it became clear that aluminium is readily absorbed from the bowel but is excreted with great difficulty by the kidney due to the overall tubular »absorption.

Preliminary examination of tine effect of aluminium «alts on the oxygen consumption of rat liver (using the manomatric technique) has indicated that aluminium is toxic for the liver. 27

14. Aluminium Toxicity in Rats G.M. Berlyne (Negev Central Hospital) and R. Yagil

Results obtained in previous experiments examining the metabolism of aluminium in rats could have been due to acidosis or dehydration (see Aluminium Metabolism in the Uraemic Rat). This experiment examines the effect on the laboratory rat of aluminium administered in various forms. Partially nephrectomised rats (1/3 functional kidney) were divided into various groups. Each group also contained rats with normal kidneys. The following treatments were given per group:

1) Two percent aluminium sulphate in water (18 mg elemental aluminium per 200 gram body weight); 2) Aluminium hydroxide in drinking water; 3) Aluminium hydroxide injected subcutaneously (60 mg elemental aluminium per 200 gram body weight); 4) Aluminium hydroxide injected intraperitoneally (30 mg elemental aluminium per 200 gram body weight); 5) Aluminium hydroxide administered through a stomach tube (200 mg elemental aluminium per 200 gram body weight).

The rats injected subcutaneously developed an aluminium granuloma. The rats injected intraperitoneally developed peritonitis. All nephrectomised rats treated with aluminium excreted red-fluid from their eyes as did some of the non-operated rats. In the serum of the rats the following was found: j - control 0.24 mg Al/1 serum; - subcutaneous non-operated 0.40 mg Al/1 serum, nephrectomised subcutaneous 2.3 mg Al/1 serum; - two percent in water non-operated 1.45 mg Al/1 serum, nepthrec- tomised 2.6 in water 39.4 mg Al/1 serum.

• • •' ••*'.." •>"''•, '•'•"•>• 28

There is no question of acidosis since aluminium hydroxide treatment gave the sam results as the sulphates and chlorides. Dehydration was also dis- qualified as the same results were obtained after subcutaneous injections when animals still drank normal amounts of water. Examination of all organs shows high quantities of aluminium, and this is especially so in the bones. Histological coupes of the eyes to examine the cause of the red exúdate have shown that the basic corneal layer is dormant; there is no mitosis and the layer is broken.

15. The Effect of High-Sulphate-Containing Water on Iodine Uptake in Rats R. Yagil, E. Bedrak, M. Ronen and G.M. Berlyne (Negev Central Hospital)

Experiments carried out on chickens have shown that water with a high sulphate content affects the passage of iodine through the digestive tract. Water in the Aravah has a high sulphate content, and thus could affect the iodine uptake in man and animal. This experiment was carried out to examine the effect of Aravah water on rats as far as thyroid function is concerned.

For purposes of this experiment white laboratory rats were divided into the following groups:

1) those receiving distilled water and maintained at 22*C; 2) those drinking distilled water and maintained at an ambient temperature of 35°C;

3) those drinking Aravah water and maintained at an ambient temperature of 22°C; 4) those drinking Aravah water and maintained at an ambient temperature of 35°C; 5) those drinking Beer Sheva water and maintained at an ambient temperature of 22°C. 29

Once a week all animals were weighed, and heart and blood was drawn from five animals in each group for thyroxine determination. The thyroxine content was determined using the tetraluteR125I-Coluira T-4 test. After two months of the various treatments each group was divided into 3 sub-groups receiving the following injections for 8 days:

1) intramuscular aqua dist. 0.5 cc per animal; 2) intramuscular KI 0.5 Цд/100 д body weight; 3) intramuscular KI 1.5 уд/100 д body weight.

After 8 days' injections all animals were injected with I and sacrificed 24 hours later. The thyroids were removed and examined for radioactivity. During the experiments it was noted that rats receiving Aravah water drank the most and also had diarrhoea. All animals maintained at 35°C drank more water than those at 22°C. The thyroxine content of the blood samples showed that the animals receiving Beer Sheva water had the most T¿. Sats drinking Aravah water and maintained at 22°C had more T- in their blood than those on distilled water at 22°C or Aravah water at 35°C.

The least amount of T4 was found in rats drinking distilled water and maintained at 35°C. Measurement of the radioactivity taken up by the thyroid gland has showed that rats drinking Beer Sheva water retained the most radioactivity, but all the groups fell within the range considered as normal. Further experiments are being carried out with larger groups of animals at 22°C to examine the effects of the high-sulphate-containing water on T3 and T4 concentrations in heart blood, radioactive iodine uptake by the thyroid gland and histology of the thyroid glands. 30

VI . STUDIES OF MEMBRANE STRUCTURE AND PERMEABILITY

1. Dehydration and Photosynthesis of Leaf Tissue Y. Graziani and A. Livne

Removal of the lower epidermis from a tobacco leaf allowed a direct examination of the photosynthetic potential of the tissue over a wide range of hydration. Dehydration in excess of 50 percent of the tissue weight resulted in an increased permeability (possibly resulting from

damaged membranes) and a decreased rate of 002 fixation. Most of the photosynthetic activities of the tissue, lost upon dehydration (up to 70 percent of the tissue's weight) is regained upon rehydration, as found in drought-tolerant lower plants (Polypodium). The return of photosynthetic activity was more effective when the rate of rehydration was slow then when it was fast. Pretreatment of tissue with polyols, which partly protected it against the increased permeability, did not prevent decreased 00- fixation as a function of water-loss. Thus, although similarly affected by the course of dehydration, the changes in permeability and photosynthesis are apparently unrelated.

2. Regulation of Water Permeability of Artificial Lipid Membranes ¥. Graziani and A. Livne

Bilayer lipid membranes were generated from various lipids, and their water permeability was determined by measuring the net volume flux produced by a Nad gradient. The osmotic permeability coefficient, P , was markedly affected by the number of double bonds in the fatty acid conjugates of the lipids: the greater the decree of unsaturstion, ;l • ' •- the higher the value of P__. By using a variety of lipids and starols, i Io" ' ' " a wide range of water permeability of the thin membranes was obtained. 31

Vasopressin, the anti-diuretic hormone, stimulates P of lecithin OS membranes; a two-fold increase was measured at 25°C in the presence of —9 10 M vasopressin. The stimulatory effect of vasopressin was linear in the range of 5 to 50 uunits/ml which corresponds to the effective physiological concentrations. Oxytocin, bov'.ne serum albumin, and a mixture of the amino acids comprising the vasopressin molecule could not substitute for vasopressin at comparable concentration. In agreement with biological -9 responses, prostaglandin E partly obviated (at 5 x 10 M) or completely •*8 negated (at 5 x 10 M) the stimulatory effect of vasopressin. The marked reduction in the temperature dependence of water permeability, caused by vasopressin, was also prevented in the presence of prostaglandin. Cyclic 3'5'-AMP with or without Mg did not change the water permeability of the thin lipid membranes, supporting the proposition that the effect of vasopressin on water permeability is independent of a mediator. The data illustrate the usefulness of a thin membrane ->del system in facilitating the study of permeability of biological membranes.

3. Vasopressin and Ion Permeability of Artificial Lipid Membranes

Y. Graziani and A. Livne

Vasopressin is known to affect both water and ion permeability of biological membranes, but the mode of action is not clear. Since the water permeability of artificial lipid membranes is markedly stimulated -9 by 10 M vasopressin, the effect of vasopressin on ion permeability in the model system was investigated. Membrane resistance was used to measure Na , К and Cl transport through the bilayer membrane. The resistance was in the common range of 2.10 to 7.1С ft/cm , and was not affected by 10~ to 10~ M vasopressin or by lO" to 10~ M cyclic AMP when a gradient of 0.3 molal, NaCl was set between both sides of the

• ¡ ' • -7 membranet These same membranes did respond to valinomycin (10 M): in the presence of KC1 a marked drop (3 orders of magnitude) was noticed in the membrane resistance following the addition of the ionophore. 32

Several conclusions are suggested by the data:

a) Use diffusive paths of water and of electrolyte molecules in the lipid membranes are distinct. b) Vasopressin apparently exerts a direct effect on the water permeability of the membrane while hormonal regulation of the ion permeability requires membrane protein components and a mediator (c AMP)„ c) The conferal of stimulation of ion permeability by vase- pressin should be a promising tool in the reconstituteon of biological-like membranes. Further work will be guided by this conclusion.

4. Erythrocyte Fragility and Potassiup. gfflux A. Saz and A. Livne

Temperature is known to affect the osmotic fragility of erythrocytes; the higher the temperature the lower the hemolysis in an hypotonic medium. The cellular site of the temperature effect and its mechanism axe not known, however. Contrary to suggestions in the literature, our study shows that the effect of temperature on hemolysis is not associated with a modified К release. Bather, the temperature-dependent fragility of red blood cells appears to be related to a direct effect of temperature on the surface area of the erythrocyte membrane. The results also substantiate the conclusion that the prelytic release of KC1 accounts for the reduced osmotic fragility under conditions where the hemolyzing rate is slow.

5. Specific Interaction of Lipids with Erythrocytes A. Raz and A. Livne

A variety of surface active lipiä compounds are known to interact with the erythrocyte membrane, as revealed by a modified osmotic fragility. 33

Since numerous compounds interact, apparently similarly, with red blood cells the phenomenon is generally regarded as non-specific. Yet,

on analyzing a series of Clg-lipids, our data indicated an intriguing specificity in structural-functional relationships. The cardinal factors were a) the number of double bonds in the hydrocarbon chain, b) the polar- end-group of the lipid, and c) the hypotonicity of the medium used for the osmotic fragility test. The differential interaction of the lipids with the erythrocytes is accentuated under conditions of high hemolysis, supporting our earlier report.

The outer surfaces of the swollen and the contracted cells are apparently dissimilar with respect to the exposed sites, indicating a "wrinkled" structure of the cell membrane.

6. The Interaction of Hashish Components with Human Erythrocytes

A. Raz, A. Schurr and A. Livne

Д'-tetrahydrocannabinal (Д'-ТНС) is the major psychoactive compound of hashish. Cannabidiol, however, is not psychoactive but serves as a precursor in the synthesis and probably in the biogenesis of Д'-ТНС in СаппаЫв sativa L.

clinical potency of tranquilizers correlates with their stabilizing potency.against hypotonic hemolysis of erythrocytes. Thus it was of interest to study the interaction of the hashish components with erythrocyte membranes.

' ' ''.,''. - '--. »»5 • • ~" - * • • ' Both components fully stabilized (at 10 M) human erythrocytes against hypotonic hemolysis, but Д'-ТНС was more active at the lower concentration range. The effect was reversible, and could be washed «way in two cycles of suspension and centrifugation. Both components increased the critical hemolytic value, but, significantly, Д'-ТНС elevated it more than cannabidiol, indicating a greater membrane expan- sion by A'-THC than by cannabidiol.

о r F 34

The interaction of the hashish components with erythrocyte raentoranes should facilitate the study of their mode of action on the nervous system. 35

VII. RESEARCH ON NITRATE REDUCTION IN PLANTS

1. Nitrite (NO2~) as Nitrate Reductase (NR) Inducer in Cotyledons of Bean Seeds D. Kaplan, N. Bejerano and H. Lips

The aim of this study was tc test the effect of two plant hormones (cytokinin and gibberellin) on the nitrate reduction mechanism in seeds. The importance of this research is that it allows more specific and precise study of the effect of hormones on the control of a known metabolic pathway than in studies on general parameters of development. During the first stage of research it was found that nitrite is much more efficient as an NR inducer than nitrate. Several experimental arti- facts were tested: NR cofactors required in the presence of NO ~ and NO ~, kinetics of the induction of enzyme activity. The result of these and other experiments show that nitrite is a very efficient inducer in bean seed cotyledons.

2. Nitrite as NR Inducer in Leaves D. Kaplan, N. Bejerano and H. Lips

A hypothesis was presented, based on experiments conducted simultaneously by N. Bejerano end H. Lips, that the NR inducer in leaves and other plant tissue is nitrite, and not, as commonly believed, nitrate. This hypothesis was tested on tobacco and barley leaves. According to the proposed theory, nitrite causes NR induction, and nitrate will be the inducer only in those tissues where conditions permit active reduction of NO. to NO. According to our theory:

a) This phenomenon is manifest in tissue where NO ~ reduction can be controlled, e.g., nitrate-deficient tobacco leaves receiving NO " in darkness, or in barley receiving NO," applications in darkness; 36

b) The kinetics of NR induction is slow in the presence of NO ~ because little NR appears upon reduction of nitrate to nitrite in the presence of a low level of constitutive NR and with a lack of reductive equivalents.

c) Induction in the presence of N02~ will be very fast and independent of a source of reductive power.

All the above assumptions assert themselves in a large number of experiments with both barley and tobacco leaves. TO date we can sum up:

a) Nitrate causes NR induction in green leaves only when reductive power is available. This happens in light because of glycolate supplied from photosynthesis, or in the dark when glycolate and NO," are exogenously supplied.

b) As the photosyiithetic mechanism in barley etiolates is not developed, the source of reductive energy is the oxidation of glucose via the pentose phosphate pathway. NR induction by NO ~ can be achieved only upon exogenous addition of glucose or glycolate which permit nitrate reduction, and as a result NO ~ appears. In both cases (a and b) nitrite causes immediate induction, independent of external energy sources.

3. NR Induction in Etiolates in Darkness N. Bejerano and H. Lips

In several studies previously published it was assumed that light is necessary for NR induction in leaves. As a result of NADP reduction in photosynthesis, ,some assumed that light was the source of reducing energy.

Little attention was paid to a British Publication showing that CX>2 was also essential for NR induction. On the basis of other studies conducted in our laboratories, we believe that both light and 00_ are essential for NR in-

duction because a product of photosynthesis is the energy source for N03~ reduction, the product of which is, in turn, essential for NR induction* To- day we are certain that this product is NO ". ,, 37

In the present series of experiments conducted on barley etiolates in darkness, it could be seen that exogenous addition of several substrates to respiration promoted MR induction by NO ~. some of the inducers are sucrose, glucose, PGA, and glycolate. Non-inducers, and sometimes inhibitors, are pyruvate succinate and acetate. He concluded that glucose, oxidized by the pentose route, supplies the energy necessary for nitrate reduction. Krebbs cycle does not supply energy to this process.

4. Glycolate Dehydrogenase - MAD and Nitrate Reduction N. Bejerano and H. Lips

TWo glycolate oxidizing enzymes, are known:

a) glycolic oxidase, which increases the rate of oxidation by passing electrons to oxygen; b) glycolic dehydrogenase, which passes electrons to an acceptor.other.than oxygen.

In our laboratory work we found that there should be an enzyme permitting oxidation of glycolate and NAD reduction, because NADH reduces N03 and glycolate permits enssymatic induction by nitrate, we found in the literature that glycolic oxidase is an enzyme of higher plants, and glycolic dehydrogenaee is the enzyme of photosynthetic algae. Purification of glycolate oxidizing enzymes from tobacco leaves showed the presence of the oxidase only.

During our experiments we found some facts which contradict previous theories:

a) There is an enzyme capable of reducing NAD coupled to glycolate oxidation. b) This enzyme can be detected in a crude enzymatic extract only under anaerobic conditions because of strong competition by glycolic oxidase. 38

с) The enzyme appears only in leaves actively reducing nitrate.

During our work we observed that glycolic dehydrogenase - HAD seemed to be part of an operon of NR in higher plants.

5. Enzyme Organization in Peroxiaomes

N. Be^erano and H. Lips

Peroxisomes have received little attention as metabolic units. One of the phenomena studied in our laboratory was the stability of enzymes bound to this subcellular particle.

It was found that glycolic oxidase is easily released from the peroxisomes particles and the latter contract due to the density of sucrose; this happens with particles obtained from plants grown in CaSO. without nitrate. When nitrate was supplied, NR appeared in the particle, and at the same time glycolic oxidase remained in the particle. Both light and hormones had the same effect. The binding stability of catalase (another enzyme typical of peroxisomes) is not influenced by the conditions under which the experimental plants were grown.

Experiments are presently being oeridücted with the sis ef discovering the site of synthesis of the enzymes and factors which influence the stability of their binding to the particle membranes, including various environmental and nutritional influences.

6. Enzyme Leakage from the Peroxisomes

H. Lips and N. Peleg

Publications in technical literature contradict each other considerably as regards the percentage of enzymes in peroxisomes» values vary between 5 percent and 60 percent. We believe this is due to failure to define experimental conditions needed to obtain a high quantity of intact particles with high enzym» content. 39

In order to find these experimental conditions the following parameters were tested:

a) Homogenization solutions - Honda, sucrose, sorbitol. b) Shape of the density gradient curve - continuous or graded. c) Concentration of the particles before layering on top of density gradient. d) Composition of the gradient - sucrose or Honda. e) Optimal homogenization solution volume/tissue ratio. f) Bate of separation in gradient. In this experiment we tested the effect of rate of particle movement through the gradient.

7. Sources of Energy for Reduction in Darkness H. Lips and R. Bruner

From our previous work and from publications by other laboratories we learned that the energy source for the reduction of nitrate in the dark is the oxidation of glucose by the pentose oxidation route. As NADPH is produced and NADH is necessary for the reduction of nitrate, it may be assumed that reducing power is obtained from a stage other than the oxL- . dation of hexoses themselves. We suggest that the source of NADH is the oxidation of glycolate to glyoxylate. This stage is identical to the oxidation of photosynthetic glycolate in light, which, in the presence of nitrate, will cause the synthesis of the appropriate amino-acids: serine, glycine, or alanine. 2hat this process exists in the dark can be proved by the following means:

a) Following radioactive tagging of glucose and glycolat*. b) Determining the dependence of serine, glycine and alanin* synthesis on the activity of the pentose oxidation process, and the availability of glycolate. 40

с) The sensitivity of the synthesis of the above amino-acids to glycolate oxidation inhibitors.

Work on this thesis has just begun. At present experimental methods i are being chosen and preliminary determination of amino-acids in plants are being made.

8. Subcellular Location of 00^ Reduction Mechanism H. bipe and V. Tsur

We tested the hypothesis that the reduction of C0_, similar to the NO ~ reduction pathway, is to be found in a subsellular particle outside the chloroplast but attached to it. The location of several enzymes essential for CO, reduction, such as carboxy-dismutase, ribulose-kinase, as well as several enzymes essential for FentOse phesphste Oiá.á-.tiOTif SüSh a~ giü0GSe-v=phS3phste^«ehydB3gSS53© and phospho-gluconate-dehydrogenase, were examined. Preliminary experiments showed that these enzymes separate from the chloroplast and are present in the fraction characteristic of peroxisomos. Currently we are concentrating our efforts on proving the presence of these enzymes in an organized particle and not in remnants of broken membranes. 41

VIII. PHOTOPHOSPHORYLATION AND ION TRANSLOCATION IN CHLOROPLASTS

1. Coupled Electron Flow and Phosphorylation in Photosystem I V. Shoshan, A. Herscovici and N. Shavit

The interaction of ATP with the energy conservation system was inves tigated further. It appears that ATP in the form of its Mg -ATP complex acts as an inhibitor of energy transfer which affects that portion of the electron transport chain that is coupled to phosphorylation. In addition, the data obtained suggest that the interaction may occur through the so- called coupling factor protein. Particles of chloroplasts devoid of coupling factor catalyze an electron flow which is not affected by ATP. At low concentrations of ATP, the interaction of an Mg -ATP complex with this protein in the membrane causes a change in permeability properties of the membrane. Under thesa conditions ATP affected the proton permeability exhibited by the membranes. Based on its specific effect on coupled electron flow, it is suggested that the electron flow associated with the photosystem I (PSI), in the partial reaction of &scorbate-»DCIP->MU-K>2 in the presence of DCMU, is indeed coupled to ATP formation. This con- troversial issue is believed to be solved now, with the postulation of site of ATP synthesis coupled to that portion of oxidation reduction reactions .

2. Resolution of Photophosphorylation V. Shoshan and N. Shavit

The separation of "coupling factor" protein from chloroplasts has until now produced a partially purified protein and particles, which when recombined formed a reconstituted particle with photophosphorylation activity. The isolated protein has a latent ATPase activity. Although these experiments prove the catalytic role of tha CF¿ protein, the reconstituted particle was only 30-40 percent active as compared to untreated chloroplasts. Therefore it was rather difficult to show reconititution of phosphorylation and control of electron transport by coupled phosphorylation. 42

A modification of the procedure for uncoupling or removing CF^ from chloroplasts rendered a particle which when reconstituted with CF^ had a high rate of phosphorylation and allowed the measurement of ATP synthesis coupled to ferricyanide photoreduction. The activity of the restored chloroplast particles was close to that of the untreated particles. Further- more, preliminary experiments indicated that the partial reconstitution attained with the usual uncoupling reconstitution procedure may be due to the removal of other factors, not removed in the modified procedure. The nature and role of the factors required for the reconstitution of an active particle and the permeability properties of the reconstituted membranes will be further investigated.

3. Mutants of R. rubrum A. Schurr and N. Shavit

The purpose of this research is to isolate mutants resistant to several agents such as uncouple» of photophosphorylation and energy transfer inhibitors from the photosynthetic bacterium R. rubvum. The electron flow chain and its coupled phosphorylation as well as several exchange reactions have been used until now to characterize the mutations isolated. Several mutants which grow on media containing (FCCP)- carbonyl cyanide-p-trifluoromethoxyphenyl hydrazone have been isolated. U appears that these mutants can grow on media with FCCP, unlike the wild strain, due to a permeability change in the cell membrane. Chromatophores isolated from the mutated cells show no greater resistance to FCCP as far as the uncoupling concentration of FCCP which is required to inhibit photophos- . phorylation. Further attempts are being' made to isolate and characterize • -- -. -•'. • • . |i . • " ' - • mutants resistant to other uncouplers and energy transfer inhibitors. 43

4. Ion Movements in Isolated Chloroplasts; lonophore-Induced Ion Uptake and its Effect on Photophosphorylation H. Degani and N. Shavit

The uptake of К or Na induced by ionophores of the nigericin type and the contribution of the electrochemical gradient of K+ to ATP formation in chloroplasts were investigated. At concentrations of KC1 and ionophores which induced К uptake but did not inhibit either H+ uptake or ATP formation, uncoupling was obtained by the consequent addition of valinomycin, which alone did not uncouple. The uncoupling by a combination of nigericin type ionophores and valinemycin was correlated to the dissipation of the alkali- metal gradient. The uncoupling of photophosphorylation in this case differs from that attained by nigericin alone since it is not concomitant with the inhibition of proton uptake. This cooperative effect among the two types of ionophores depended on the external concentration of KCl and did not occur in NaCl medium. The contribution of a membrane potential to energy conservation ÍR 44

IX. PHYSIOLOGY OF PLANT SENESCENCE ANO MECHANISMS INVOLVED IN THE ADAPTATION OF PLANTS TO STRESS

1. Mineral Deprivation and Abscisic Acid (ABA)

A. Richmond and Y. Mizrahi

Tho purpose of this work was to find out whether the leaf content of ABA increases under stresses unrelated to the water-balance of plants. The methods consisted of quantitative analysis of abscisic acid in leaves of tobacco plants grown in half-Hoagland solution, then transferred to distilled water. The abscisic acid content of leaves in mineral-deprived plants rose continuously throughout the seven days of the experimental period. How- ever, although the content of abscisic acid had already risen within 24 hours, a decline in growth and leaf-chlorophyll was discernible only after the fourth day of mineral deprivation. As anticipated, mineral-deprived (stressed) plants exhibit "resistance" to lack of aeration in the root medium similar to that shown in salt-stressed plants or plants that were pretreated with abscisic acid. When the mineral-deprived plants were returned to half-Hoagland, the content of leaf-abscisic acid declined to the prestressed level and the "resistance" to lack of root aeration disappeared. These results indicate that an increase in abscisic acid may be induced by conditions unfavorable to growth in general and not exclusively by conditions affecting the plant's water balance. In addition, the work also indicates that mineral deficiency is associated with significant modification in the hormonal balance of the plante 45

2. Metabolism of Nucleic Acids Associated with Adaptation to Salinity

A. Richmond and Y. Mizrahi

The object of this work was to characterize RNA formed in the cells during adaptation to conditions of stress. Tobacco plants were exposed to 24 hours of salinity and carrier free P . The plants were then transferred for varying periods, up to 7 days, to Hoagland solution containing non-radioactive phosphorous. Profiles of phenol-extracted nucleic acid on MAK-column chromatography indicate the following:

a) The specific activity (sp. act.) of all RNA fractions is lower in the saline plants.

b) In the control plants, the rise in specific activity could be measured for 48 hours after initiation of stress. In contrast, plants showed a continuous increase in sp. act. of all the nucleic acid fractions until the end of the experiment on the 7th day.

Techniques in nucleic acid hybridization were used to compare the extent of the active genome in salinated plants with that of the controls. In both treatments the active genome was found to be similar and about 2 percent of the total quantity of ША, which conforms with data about other organisms. Further experiments are being carried out to investigate the hypothesis of a qualitative difference between! the RNA product of the stress genome and that of the control.

3. The Mode of Action of Kinetin in Delaying Salt-Induced Necrosis in Tobacco Leaves

A. Richmond, Y. Mizrahi and A. Ben-Zioni

; Treatment of plants subjected to salt stress with kinetin shows that the appearance of salt-induced necrosis in the treated leaves is delayed for up to 3 weeks after its appearance in the control plants (salt stress without addition of hormones). 46

The delay in damage was probably due to the effect of kinetin on the reduction in the accumulation of Cl and Na ions in the leaves.

Plants were analyzed for Cl and Ha ions when the damage was first observed in the controls. The results indicated that treatment with kinetin reduces the concentration of salt ions in leaves and expcr- iments with Cl and Na support these results. It should be noted that in these experiments pretreatment alone could not cause a significant effect, and for maximal effect, the hormone had to be present throughout the duration of the saline-stress.

These results are supported by findings in the literature, and indicate a possible role of cytokinins in uptake and transfer of ions in the plant.

A secondary phenomenon observed in these experiments was that addition of kinetin to the root causes dwarfism in plants, which seems to have a significant theoretical and practical potential.

4. Use of Abscisic Acid (ADA) in Ameliorating Drought Conditions for Plants

Л. Richmond and Y. Mizrahi

ABA concentration was found to increase in leaves of plants subjected to stress. It was hypothesized that the hormone plays a role in regulating plant adaptation to stress. Hence the premise that pretreatment with ABA should improve the condition of plants subjected to drought.

Barley seeds were planted in local loess soil saturated to field capacity, and no water was added during the experiment. ABA was sprayed л on every 3 days after the appearance of the first leaf.

Life-span of the plants treated with ABA was extended by about two weeks as compared with that of the controls. Increasing the concentration of ABA sprayed on the shoot resulted in increased soil and leaf water content. Significantly, certain concentrations of ABA affect retention of chlorophyll under these conditions. Also, preliminary observations indicate that treatment with ABA may increase the efficiency of water 47

utilizatiмл, a parameter that measures the ratio between the amount of net dry natter produced per plant and the amount of water used.

5. Relationship Between ABA and Drought Hardening Treatments in Barley and Wheat Seeds A. Richmond and Y. Mizrahi

Some Russian and Australian researchers report that drought resistance may be enhanced in plants cultivated from seeds which have undergone a cycle of drying during germination. It is assumed that if this phenomenon actually occurs it emanates from the rise in the endogenous content of ABA due to the drying treatment.

wheat and barley seeds were subjected to the "hardening" treatment. The efficiency of the treatment was tested by measuring the response of seedlings to water-stress and measuring the seedling content of ABA.

ABA concentration increased only slightly in seeds subjected to the hardening treatment.

We have not yet succeeded in growing drought resistant seedlings from treated seeds as we did succeed with the ABA spraying treatment.

Attempts to impart drought resistance by treating seeds with ABA were relatively less successful than those obtained from spraying ABA. We concluded that spraying the seedling with ABA is more effective than seed-treatment; un- less a new method can be evolved (e.g., coating) which should release ABA in small amounts over an extended period.

6. Interactions Between Cytokinins and Gibberellin

A. Richmond and A. Back

The investigation related to the question of whether the retardation of senescence by gibberellin is due to an increase in, or at least to the maintenance of, the level of leaf-cytokinine. Application off gibber*lliс acid to whole, uncut lettuce increased the level of cytokinins. This phenomenon is currently being investigated in tobacco as well as in Riomx and in Tropaeolum. ',' ' / 48

The influence of kinetin, GA and ABA on ethylene emanation from leaf discs and whole detached leaves of Rwrex and Tvopaeolwn is being investigated. Our purpose is to test the hypothesis that these hormones affect senescence in detached leaves by affecting the production of ethylene. Preliminary results do not support this possibility.

7. Retardation of Senescence in Lettuce by use of Plant Hormones A. Richmond and A. Back

The effect of a combination of cytokinins and gibberellic acid on lettuce-senescence was investigated. Optimal combinations were found for retarding yellowing and rotting in lettuce. Application of the growth factors for up to one week before picking indicated that lettuce could be kept refrigerated for 3 weeks and then stored for 3 days on shelves о Refrigeration could be stopped for 24 hours without any damage.

Measurement of residual gibberellic acid in sprayed lettuce leaves showed that during this period of refrigeration and shelf-life, the quantity of residual gibberellin was reduced 100-fold.

8. Modification of tRNA During Senescence of Leaves of Tobacco Plants A. Richmond and I. Natan

In the early stages of leaf senescence, there is a great loss in the amount of chloroplast tRNA and in amino-acyl synthetase activity. There is also a definite qualitative change as evidenced by the modification in the relative quantities of leucine isoacceptors. 49

9. Location and Identity of RNase in Leaf Cells of Barley Plants Exposed to Drought and Salt Stress A. Richmond and S. Arad

The object of this study is a) examination of RNase activity in leaves of plante exposed to drought and salt stress, b) investigation of the effect of kinetin and ABA on RNaae activity, c) identification of stress-induced isoenzyntes of RNase, and d) location of the changes in enzyme activity in leaf-cells of stressed plants. Using standard methods, RNase activity was measured in leaves of drought-stressed barley seedlings. The seeds were sown in soil watered to field capacity with no additional subsequent watering. During this experiment varying hormone concentrations were sprayed on, once each for 3 days. In other experiments, RNase activity was examined in barley plants grown in salinated (20 g/liter NaCl) Hoagland solution.

Exposure to drought results in an increase in RNase activity. This increase is in direct correlation with the extent of leaf water saturation deficit (W.S.D.) which increases as a result of water stress.

In these experimental conditions, spraying with ABA reduced enzyme activity in comparison with that of untreated plants, thus maintaining enzyme activity at & level appropriate to the W.S.D.

In comparison and in agreement with the literature, ageing detached leaves in which no decrease in leaf-water content occurred, increased and decreased enzyme activity on treatment with ABA and kinetin respectively.

10. The Effect of Stress on Hormonal Balance in Plants

С Itai and A. Ben-Zioni

, The purpose of this work was to study the effect of osmotic stress on roots and on endogenous levels of hormones in xylem exúdate.

It is known that after a plant is subjected to osmotic stress there is an increase in ABA levels in the shoot and a decrease in cytokinin 50

levels in the roots. It was proposed that the decrease in cytokinins is caused by the rise in ABA which is itself caused by water deficiencies in the leaves. Our experiments indicate that when the roots of whole plants are subjected to stress the cytokinin level in the xylem exúdate goes down and ABA levels are increased. But when the stress was applied to plants detopped before being exposed to the stress, cytokinin levels decreased while ABA levels did not change considerably. These results suggest that the response to osmotic stress is composed of two different mechanisms which are not necessarily dependent on each other. In another experiment the connection between changes in ABA and cytokinins was determined in detached leaves which were exposed to atmospheric stress for different periods. It was concluded that in this system, as in the first, there is no correlation between changes in ABA and cytokinins. The rise in ABA levels as affected by atmospheric stress was rapid and great; it could be seen within 20-30 minutes from the beginning of the stress. Endogenous cytokinin levels did not change in a similar manner or to the same extent.

11. Effects of Temperature on Detached Leaves C. Itai and A. Ben-Zioni

The aim of the investigation is to discover the phenomena involved in plant response to heat stress and to increase our knowledge of their regulation. Exposure of a leaf to temperature of 47.5°C will enhance its senescence. CO_ fixation was reduced due..to heat-treatment. Since transpiration is enhanced it was concluded that the reduction in fixation was not due to an increase in resistance to C0_. The reduction of fixation is temporary, and 48 hours after heat exposure the ability of the treated leaf to fix CO, is fully recovered* Nonetheless, the rate of 00, fixation continued to decrease for 6 hours after the treatment. 51

The assumption that the intermediates of the Calvin cycle are lost either 1) due to activation of a competitive cycle, or 2) due to membrane leakage, was tested. The first possibility was tested by following changes in respiration. It was found that respiration is enhanced due to heat treatment. The second possibility was investigated by studying the efflux of Cl from the cell. It was found that efflux is enhanced by the treatment. An effort is now under way to establish tlie primary damage. The reversibility of those processes associated with heat treatment was also studied. Three factors were found to participate in the reversal of the treatment at 48°C. 1) It was found that 48 hours

after the treatment the rate of C02 fixation and Cl efflux is equal to those of the controls. Water loss is reversed within 24 hours after the treatment. 2) Kinetin was found to partly reverse respiration and efflux. 3) Cold treatment (10°-7°C) immediately after heat treatment inhibited the increase of respiration due to heat treatment.

12. Effect of Salt or Heat Stress on Lipid and В-Glucan Synthetase in Plants

L. Ordin, Л. Ben-Zioni and C. Itai

Niaotima rustica plants were exposed to salt stress (18 g NaCl per 3 liters) and 18 hours later growth and glycosyl transf erase (synthetase) levels were determined. The glycosyl transfers assayed were those involving transfer of glucose from ШР glucose (glucose-14C) to lipid, NaOH-soluble glucan and NaOH-insoluble glucan. These are particulate enzymes. Although leaf area growth was inhibited about 50 percent, lipid synthetase was unaffected while the glucan synthetases were slightly stimulated. Enzyme (about 1000 ]xg protein) from control plants incorporated (from about 55,000 cpm) 3300 cpm per 100 yg protein into lipid, 330 cpm into NaOH-soluble glucan, and 125 cpm into NaOH-insoluble glucan. The effect of heat stress was also examined. Discs of tobacco leaves were dipped into a 47.5°C water bath for 2 minutes. After 3 days on H strength Hoagland + 2% sucrose solution, disc weight increase was measured. Growth was inhibited nearly 100%, 52

One hour after the heat treatment, all 3 synthetases declined 30 percent to 40 percent. Three days later control lipid synthetase declined slightly. She glucan synthetases declined even more strongly so that inhibition compared to control at 3 days was enhanced. Apparently damage to membranes (not visible to the eye) had occurred. CeHuíase treatment of the alkali- insoluble product showed that the product was mainly 0 1,3 glucan. Since it was mainly a cellulose-producing system that was of interest, the plant species examined was changed to Phaseolus vutgarie where cellulose was produced from OOP glucose.

A series of heat-stress experiments were carried out. After a heat shock to roots (46°C, 2 minutes), primary leaves showed a 50 percent inhibition of growth after 24 hours. Lipid synthetase was not affected in a con- sistent manner so that the overall effect was nil. Glucan synthetases, on the other hand, were stimulated* Apparently indirect treatments resulting in short term growth retardation resulted in a conservation of glucan synthetase levels. 14CO, fixation in such plants was not affected. Further work to distinguish the glucan synthetaee by organelle location in control «.id heat-treated plants is planned. 53

X. PLANT INTRODUCTION AND ECOLOGY

This Department investigates the suitability of various plants and crops to the soil, water and climatic conditions of the Negev. At the beginning of its activity/ the work of the Department largely c onsisted of general observations of growth and behavior of a wide range of species. As work progressed, however, the necessity for more detailed research increased, and investigation focused on specific groups of plants related to specific problems. The major current projects in the Department; include; 1) Introduction of drought and salt resistant fodder plants for increasing the carrying capacity of the area under its natural conditions. Palatability trials were continued at Higda. A new area was planted in Magen for checking the specific contributions of particular species to pastures. A series of recently introduced species was planted in Omer and Magen. 2) Utilization of the brackish water, which is abundant in the region, for irrigation of salt tolerant and resistant species for agricultural, landscaping and gardening purposes. Trial irrigation of cotton with brackish water was carried out at Mashabei Sade in summer 1971, and saline irrigation of wheat was initiated during the winter months. A literature survey of salt resistance of trees is under way, and preparations for trials have been made. 3) Introduction of trees, shrubs and cover plants for gardening and landscaping in arid and semi-arid conditions. In cooperation with the Forestry Division/ Ilanot/ and Keren Kayemet Le-lsrael, a survival survey of trees was carried out in the elimination plots scattered through the Negev. Studies of the landscaping and gardening problems of Arad were initiated. In particular* the soil characteristics of the area were investigated. 54

4) Utilization of favorable environmental conditions for the cultivation of special crops. Investigations of various aspects of Pistachio nut cultivation were continued. Preliminary studies on the propagation, cultivation and use of medicinal plants were started. Work on some aspects of the cultivation of Simnandsia ckinensie was continued.

•• 1 55

1= Introduction of Fodder Plants

M. Forti and Y. Levi

Die introduction of drought-resistant perennial fodder plants is intended to increase the present animal carrying capacity of the Negev area. Their integration in the pasture system would assist in overcoming grazing or feeding difficulties in the critical periods of the annual cycle as well as in severe drought years.

After a preliminary screening in the nursery and under improved conditions in the introduction plots at Beer sheva,. the various species are tested under natural conditions in four permanent areas (Omer I, Osier II, Gvulot and Wadi Secher) . In these tests the plants are not irrigated or cultivated. Factors such as growth, phenology, re-seeding, volunteering, and competititve ability are examined.

In the period under survey no close follow up of the old plan- tations (1965-1966-1967) took place.

Results continue to confirm the ability of a number of species to grow and to produce in the loessial soils of the Northern Negev. So far only a few species (particularly Atriplex caneeaens and А. сапеваепв, sap. linearte) appear suitable for the soils of the Western Negev (sand over- laying loessial soils) and none appear to be able to survivs in the deep sand dunes south of Beer Sheva.

A new series of species, consisting mainly of Atriplex ар. Koahias and a few Aoaoiaa, was planted in Omer and simultaneously in Hagen in the Western Negev (this site was preferred to Gvulot, since the future of the old introduction plot appears to be doubtful).

Fodder •hrube continued to arouse the interest of various organizations in Israel and abroad» Seeds ware supplied to the Faculty of Agricultural Engineering, the Technion, Haifa (Prof. Z. Navah) for landscape beautification and road consolidation, to the Ministry of Agriculture, Safad, for road consolidation and grazing purposes, and to the Ministry of Agriculture, Administration of Judea and Samaria, for grazing purposes. 56

Plants were supplied to the project at Wadi Mashash {Prof. Evenari) to the Magen farm (grazing) and to Habesor Park (landscape improvement). The Israeli Commission which visited Latin America to study the possibility of creating various institutions for arid zone research re- commended the exchange of information and specialists between Israel and South American countries. As a result M. Forti participated in the Inter- national Congress on Arid Zones, which was held in Arica (Chile) in August 1971, and afterwards visited Chile, Argentina, Brazil and Mexico, concentrating on areas and organizations involved with pasture problems. Seeds were collected in the different countries, and the seeds of various species used by the Department were supplied to Latin-American Institutions.

2. Palatability Trials with Awassi Sheep M. Forti, Y. Levi, S. Owardi, R. Benjamin (Volcará Institute) E. Eyal (Volcani Institute) and N. Tadmor (Hebrew University, Jerusalem).

As stated previously, encouraging results were obtained concerning the ability of certain shrubs to grow in the loessial soils of the Northern Negev under conditions of drought. No information was available, however, concerning their use as fodder plants under Israeli conditions. In order to test the grazing potential of the various species, about 110 dunans were planted at the Higda farm in Hay-June 1968 with 22 specie^ selected from the numerous ones previously tried in the loessial soils. Two main areas, identical in surface and plant composition, were established. Botín, had the same number of replicates (12), each of which, in turn, was composed of 20 blocks, one for every species. One area was fenced into 12 plots (or replicates) and sheep were moved monthly from on* plot to the next, thus permitting observation of palatability and palatability fluctuations during the grazing cycle, ttie second area was left undivided in order to give information on the resistance of species 57

subjected to continuous grazing over a long period. On both areas 18 sheep were permitted to graze freely day and night. In the period under survey the results of the first year's (March 1970 - March 1971) trials were generally confirmed: a) No species were absolutely refused. A scale of priority, however, could be established according to the chronological order and to the rapidity with which the different species were eaten. b) Ceceeia eturbii continued to perform well throughout the year. AtHplex canescem was outstanding in the warm season and A. nianmlaria in the cool months'. Acacia cyanophylla also excelled for most of the year. Some of the other species showed their best performance over short periods. Other plants, while palatable per se, showed disadvantages inherent in their habitus which reduced their pastoral value. c) During the experiment the sheep lived on fodder plants and natural vegetation only. Die general trend in both areas was weight increase. In the continuous grazing portion the mean increase was 11 kg. In the rotational grazing area,, it was smaller (7 kg as a mean in the period under survey) and weight fluctuated considerably, generally reaching its highest levels in.the first two weeks of grazing in a given replicate and declining towards the end of the period. la both portions the characteristic seasonal weight decrease in December - January could mot be prevented. It was slighter in the continuous grazing area, more substantial in the rotational one* The weight increase mentioned above was in addition to that of 1970-71 when the animals experienced their maximum growth. d) Many species showed an excellent recovery ability. Ihe ••cond grazing year was important from the point of view of selection as a result of the combined effects of recovery ability, grazing resistance and adaptation of plant* to the local conditions. Most of the gramínea* were not able to withstand the trial conditions. AtHpUx leucollada 58

and Galenia secunda almost disappeared. Koohia georgei, K. prostrata, Osteospermum ainuatim and 0. paahypterie showed a weak and decreasing performance.

3. Grazing Trials on Selected Fodder Shrubs

M. Forti

The experiments carried out at Migda indicate the different degrees of palatability of various fodder shrubs and enable establishment of a priority scale based on sheep response. They do not give any indication of the contribution of a particular species to the nutritional needs of grazing animals. For a better evaluation of the plants' values and yields, the best species must be planted and grazed separately and their performance compared.

In summer and fall of 1970 about 10,000 seedlings of Atriplex nuimularia and Cassia s tur Hi were prepared in the nursery of the Depart- ment for use in a comparative grazing trial to be carried out with cattle at Kibbutz Lahav. The Kibbutz, however, withdrew from the program, and the experiment had to be postponed.

Towards winter of 1971-72 Kibbutz Magen offered to carry out the trials. To meet the new trial conditions, the original plan was revised in several respects, including; a) use of sheep instead of cattle;

b) inclusion of Atriplex eanesaene and A. oanesoens3 вар. linearte in the plant list (as the most reliable species under the conditions of the Western Negev); and c) possible use of Aoaoia oyanophylla as a further control (in addition to the natural pasture originally planned) since this species is intensively planted and utilized by the farm for grazing purposes,

The additional species were prepared in 1971, and planting took place in March 1972. 59

Three plots , each of 10.5 dunams, were each planted with one of the selected species, A. nwrmdaria, А. oaneeaens and Cassia stuetii. A fourth plot was planted with a mixture of the species mentioned. Иге seedlings of A. eaneeaens, esp. lineaxis were severely injured in the nursery, probably as a consequence of the meteorological conditions of winter 1971-72. There were only enough surviving plants to plant half the intended area. Planting will be completed in the next year.

In all, an area of about 47 dunams has been planted with 5500 seedlings. Soil conditions at planting time were excellent. This and the abundant winter rainfall may enable establishment of the experimental plots without any additional irrigation.

4. Pistachio Nut (P. vera)

A. Milner-Nevo

Work on the pistachio-nut project was largely the continuation of previously started studies, with some modifications. Attention focused on the following subjects:

a) Production of container-grown seedlings. The first and principal phase was completed. Results are positive; it is possible and practical to produce container (plastic bags) grown seedlings. The method was found preferable to the common one - bare-rooted seedlings grown in soil - in several respects.

b) Budding and grafting. The subject has proved extremly problematic and complicated. Much work was done in order to determine the factors responsible for the regularly very low take. Results so far have been erratic.

c) Pollination. Surveying and mapping of blooming tima (male- female) was continued. Preliminary work was started on the development of a mechanical pollen collector. More work was don* on pollen preservation and viability teats, and on artificial pollination. Another set of controlled 60

pollination experiments was carried out in order to check the possible influences of different males on the quality of the fruit.

d) Dormancy breaking. A large scale experiment (5 plots in various areas in the Nsgev) was conducted to compare different treatments and to determine their practical efficiency. Results are interesting and have possible applications. e) Shell Splitting. Two approaches to the problem have been tried:

- Pre-harvest treatments, mostly utilizing agrotechnical methods, which have brought some limited positive results. - Post-harvest treatments, mostly chemical and mechanical, with erratic results.

In addition, work has continued on general phenological surveys, observations of stock, cultivar relations and follow-up of performance and yield in order to evaluate qualities of varieties and of individual trees. The establishment of an experimental plot at Mashabei Sade to investigate salt tolerance of the crop was begun. Work was continued in Judea and Samaria. It included the establishment of a new plot, as well as top working a plot of old trees (of inferior quality) in order to compare and evaluate new varieties. several publications were put out including reports, reviews, research programs and an instruction booklet (in Arabic). Contacts were continued and expanded with people and institutes engaged in similar work, both in Israel and abroad.

5. Medicinal Plants

A. Milner-Nevo

During the past year studies an the growth and production of aadic- inal plants have begun. Preliminary results have shown some positive potential. 61

6. Utilization of Saline Water for Irrigation of Salt Tolerant Crops M. Twersky and D. Pasternak

The objectives of this project are: a) to utilize the large resources of saline water in the Negev for agricultural purposes by demonstrating irrigation practices with brackish water and to define associated agromanagement problems, b) to study the macro-physiological response of plants to salt stresses and to determine ways of alleviating these stresses; and c) to look for those species and genotypes adapted to higher levels of salinity.

X. Growth and Performance of Cotton. Cotton (Acala SJ-1) was planted at Hashabei Sade in May 1971, irrigated with brackish water containing 2500 ppm and good water containing 700 ppm total dissolved salts, and har- vested during the latter part of October 1971. Brackish water yields (486 kg/d) were 59 percent higher than fresh water yields (285 kg/d). A total of 847 mm water was applied during the growing season, of which 512 mm was brackish water. Preliminary field results have been summarized (Hebrew) .

II. Wheat, a) Field experiments: wheat was planted at Hashabei Sade in December 1971. Two experiments are under way. The first investigates the effects of irrigation with brackish water under accepted local practices and under conditions of high fertilization and frequent irrigations. The second investigates the effect of saline water on those developmental stages at which wheat may be especially sensitive to salt stress, b) Glasshouse experiments: Three experiments are under way. The first is complementary to the field work and examines the effects of saline stresses in the wheat plant at various developmental stages. The aims of the second are to establish the limits of the resistance of wheat to salinity and to study techniques suitable for physiological work. The third is designed to study mechanism* involved in salinity stress of whole plants. All glasshouse experiments are presently being conducted on a preliminary basis. . 62

III. Development of forage production with salt-resistant forage crops. Rhodes grass, c.v. Katambora, and Bermuda grass, c.v. Suwannee are being established at Mashabei Sade för determination under field conditions of saline water-fertilizer interactions in a long-term water management program. A comprehensive literature review has been completed in conjunction with this particular project. IV. Utilization of discarded brines from desalination processes. Methods are being considered for utilizing the end brine concentrate from the Mashabei Sade desalination plant in forage production. Work will start in 1972. The short-term (3 years) goals of this project are a) to bring about the utilization of the saline aquifer of the Western and Central Negev for agricultural purposes, b) to find agricultural uses for the end brine water from the desalination plant at Mashabei Sade, and c) to establish agro- fertilization practices for crops irrigated with saline waters. Hie long-term (7 years) goals are a) a continuation of the brine water trials to select species that will grow economically under high saline irrigation, b) with the knowledge of the physiological processes involved in salinity stress acquired in Part &j to determine 1) agrotechnical methods to increase yield of crops grown under saline conditions, and 2) to establish guidelines for selection and breeding of salt resistance in plants.

7. Departmental Soils Laboratory

Routine and research analyses of the properties.of soils of interest to the Plant Introduction and Ecology Department have been carried out. Ser- vices include analysis of electrical conductivity of soil, water, and plant samples. Determinations were made of soil water retention curves, of particle- size distribution in the soils, and of other related soil properties, as required. Approximately 500 soil samples passed through the Soils Laboratory in 1971. 63

8. Investigations of the Salt Tolerance of Trees Suitable for Brackish Water Irrigation S. Kaplan, I. Borowitz, M. Fcrti and S. Aklufi

The object of this work is the determination and selection of trees tolerant to saline water which nay be useful in establishing parks and in afforestation projects in the Negev. After a thorough literature search 10 species of trees have been selected for experimentation. Trials will begin this spring. Techniques have been developed for conducting the experiments, and critical peri- pheral information, such as properties of the soil to be used, have been obtained. Bach species will be subjected to four salinity treatments ranging from 3,000 - 12,000 ppm NaCl, plus a fresh water control. The species which show the most toleiance will be subjected to further experimentation to determine the effects of increasing water potential due to non-osmotic factors.

9. Effects of Salt Pollution on the Flora of the Negev S. Kaplan

The purpose of this work is to determine the tolerance of natural and segetal vegetation in various parts of the Negev to increasing soil salinity. Increasing soil salinity is the result of fresh and salt water irrigation programs; such programs are now in use in the Arava region and on an experimental basis at Mashabei Sade, Habesor Park and the Negev Institute. At Mashabei Sade a plot has been established, one-half of which is being irrigated with fresh water and one-half with saline water» Plants growing in the area have been collected for investigation. Measurement of plant growth, abundance and:distribution will be made at the station at Mashabei Sade* Greenhouse and pot experiments will mmm 64

be conducted on the plants collected to determine the influence of saline water on germination, growth and development.

10. Cultivation of Sirmondsia akineneie

M. Forti

Sivmmåaia is an American shrub native to the arid zones of California, Arizona and New Mexico. The nut contains a liquid wax in concentrations of up to 50 percent. The wax is a potential substitute for sperm whale oil and has been proposed for use in the dietetic, cosmetic, chemical, lubricant and other industries.

SitmandBia was introduced in the early sixties by the Department and has been grown satisfactorily in the loesaial soils of the 200-250 mm rainfall area of the Northern Negev in both irrigated (200 mm water/year in addition to rainfall) and non-irrigated plots.

In the period under review the work in the adult plots was limited to the most essential operations - cultivation and (where practiced) irrigation. Individual plant yields, however, continued to be systematically recorded as they are one of the most important parameters in the selection of outstanding types.

11. Improvement of Sitwiandjsia ehineeis

M. Forti and M. Tal

A preliminary survey on the variation of reproductive and vegetative characteristics ef Sirmonåsia скгпепвгв was carried out in 1966, and the data collected enabled a series of crosses between selected individuals to be carried out. The F, seedlings obtained were planted in 1968 and 1969 in two plots at the Negev Institute. Host of the plants in the 1968 plot started yielding last year and a few in the 1969 area yielded this year.

It is planned to «elect those plants from the Fj, group which show outstanding characteristics with respect to both vegetative and reproductive traits. Work will start in May 1972. 65

Additional crosses between male and female of the same F progeny were carried out in the early spring of 1971 with the intent of uncovering desirable recessive traits hidden in the F plants. The seedlings obtained are now ready for planting.

12. Plant Introduction in the City of Arad

S. Aklufi

The city of Arad is located 35° 13* longitude E, 31° 15* latitude N, at about 600 meters elevation, along the 100 millimeter isohyet.

Within the undulating hilly sites of the city, no soils of horticul- tural value are to be found.

The top soils of Arad are shallow (to 18 cm in depth), consisting of loessial sierozems and brown lithosols strewn with chert. Loess deposits are rare. The natural vegetation is restricted to ephemerals.

In attempting to establish plant communities in the gardens of Arad, the chalky conglomerate deposits were found to be a tolerable "soil" medium. The marl, chalky marl deposits underlain with limestone rock, 'is considered very poor by the local inhabitants.

Aridity, salinity (more than 10 millimhos/cm), alkalinity, possible boron toxicity (about 4 ppm), the highly calcareous nature of the deposits (40-90 percent) as well as their highly variable and unfavorable physical characteristics, make it difficult to establish plants in Arad.

Marl is normally used as an amendment to lime-deficient soils. It

.. is_a_ loosely consolidated depositTof limestone with "impurities"ot—sand, - silt and clay (10-60 percent). Its hydraulic conductivity and thus its leaching capabilities are dependent on structure, particle size distribution, particularly the clay fraction and the dominant clay mineral present. • '• - '.'''"' *•'••''',/" 66

Laboratory studies indicate that when the marl and limestone are broken into aggregates (15 mm in size) hydraulic conductivity can be enhanced and leaching of toxic salts is possible. Hie rate and extent of hydrolysis (slaking) is under investigation.

Field studies are planned to mechanically disrupt and mix the marl, chalky marl and limestone rock to a depth of a meter, and study in aitUi hydraulic conductivity, permeability and salinity.

A selection of trees and shrubs has been chosen for planting that meets in part or in full the limiting factors of Arad. In previous reports» methods to ameliorate the unfavorable "soil" properties in the gardens of Arad were proposed. The help of Mr. Raphael, toroi engineer, in carrying out such trials is hereby gratefully acknowledged.

13. Tree Introduction Trials in the Negev

S. Aklufi

A survey of tree and shrub survival and total growth to date at sixteen tree introduction trial sites in the semi-arid and arid parts of the Negev was recently carried out. These elimination trials of 10-15 year duration are the joint effort of Keren Kayemeth, Ilanot and the Negev Institute for Arid Zone Research. The sites vary in amount of pre- cipitation, ebile and exposures. Whether the elimination trials indicate a true selection of plants that can survive and thrive in the «rid or the semi-arid zones of the Negev is a matter of conjectur*. =.-•=-.--^------

Plant, site-weather, and soil-water need to be evaluated as a unit. Plant exotics introduced from different climatic areas often display variable inherent response to critical environmental factors. Few studies have been made of genetic adaptation to soil differences. . 67

Possible approaches include:

1) The siting of the plots as they relate to such local conditions as relief and exposure (microclimate). 2) Water-shed, water-receiving (plant site) ratios need to be determined and established. 3) Choice of plant varieties that can withstand occasional drought. 4) Agrotechnical management such as: a) pre-planting care of plant in the nursery row to prepare it for its planting site, and b) plot orientation, preparation and method of planting and subsequent care of the plants which reflect arid conditions. 68

XI. HUMAN PHYSIOLOGICAL AND PSYCHOLOGICAL BEHAVIOR UNDER HEAT STRESS

1. Acclimatization to Severe Dry Heat by Brief Exposures to Humid Heat in Summer ana winter

E. shvartz and D. Benor

This study was conducted in the summer of 1971 as pari; of an investigation that began in the winter of the same year. The ригрозе was to determine the effect of brief exposures to humid heat on tolerance to severe dry heat in winter and summer. Fourteen young men served as subjects. Hie results indicated that this method of acclimatization in summer was less effective than in winter. The method used in the winter had been very effective.

This study was supported by a grant from the Sports Authority, Ministry of Education and Culture, Israel.

2. Methods of Acclimatization to Severe Dry Heat

E. Saar and D. Benor

This study was conducted in the winter of 1972 as an extension of the above study. Three methods of acclimatization to severe dry heat were compared: exposure to dry heat, exposure to humid heat and physical train- ing alone. Twenty-one subjects were used. The results are being analyzed.

3. Human Performance During Thermal Stress

M. ititman

This study set out to investigate a possible correlation between levels of anxiety and human performance in high environmental teaparatures. Eight university students acclimatized to work in heat took th« Taylor Test 69

of Manifest Anxiety. According to their scores on the anxiety scale they were classified as anxious and non-anxious. The experimental procedure consisted of the subjects sitting in a hot room (45°C ambient tempe-ature, relative humdity less than 40 percent) for three consecutive hours. Con- trol experiments were carried out at 25°C on the same subjects. The order of experiments were randomized. Preliminary results indicate that decision making, choice reaction time and micromotion were unaffected by thermal stress, physical fitness or degree of anxiety. It can also be inferred that the more anxious subjects performed better during the second and subsequent exposures irrespective of environmental temperatures.

This experiment was done with the technical assistance of Dr. Chela Schechter

4. Human Perception and Performance M. Litman

In order to evaluate the effects of thermal stress on human perception and performance in a situation where agility and decision making are of paramount importance, eight healthy young students were exposed for three consecutive hours to thermal stress (ambient temperature 45 C, relative humidity below 40 percent). At regular intervals choice reaction time, visuo-motor coordination, accuracy and micromotion were tested.

Control experiments were conducted at 25°C. Drinking water was supplied freely throughout the experiments. Preliminary results indicated that under the described thermal stress there was no deterioration in performance, The distribution test failed to show any significant difference between heat stress and comfort conditions.

This experiment was done with the technical assistance of Dr. Chela Schechter 70'

5. Two Prototypes of Water Cooling Garments

M. latinan and A. Shots

In order to minimize the serious effects of heat stress in hot, dry climates where environmental cooling is not practical, two prototypes of water cooling garments (W.C.G.) were developed. Both garments covered approximately 35 percent of the body surface (the torso) and were made from two layers of thin welded polyvinyl chloride (FVC). They were manufactured by Chemoplast, Afula.

The two prototypes were made by welding together layers of PVC in which the cooling channels were molded in a labyrinthic pattern. The prototypes differed only in that the channels of one were connected in series while a series-parallel arrangement was used in the other.

No significant difference was observed in the cooling effects of the two suits. However the vest with the series-parallel arrangement exhibited lower resistance to flow while the one with the series arrangement proved easier to design and construct.

Both succeeded in permitting the subjects to achieve an operational goal of two hours work in thermal stress conditions (50°C Та) with minimal strain on the cardiovascular and thermoregulatory system. Rectal temperature and mean skin temperature remained below S8°C and 34°C~ respectively after the two hour walk while heart rate fluctuated around 125 beats per minute.

Further improvements are required in closeness of fit and uniformity of flow.

6. Partial Body Cooling with a Water Cooling Garment

M. Litman and E. Rappeport

A water-cooled garment different from other such garments was designed using gravitational film flow instead of forced circulation through tubes. 71

The suit under trial was a vest covering about 35 percent of body surface, with the cooling fluid (tap water) distributed evenly at the shoulders and axillae. This distribution was achieved by a" series of openings spaced at approximately 4 cm. Water flows from the openings and spreads between the inner and median layers of the vest so that the skin and the cool inner layer are in close contact. The aim of the individual cooling is to remove metabolic heat production and to minimize environmental heat load to prevent the detrimental effects of heat stress in situations where environmental cooling is not feasible.

The effectiveness of partial body cooling was assessed by exposing healthy subjects to heat stress (walking at 5 k.p.h. at 50°C ambient temperature for 2 hours) and comparing the reduced physiological strain with the cooling suit to the results from control experiments at 25°C. The physiological parameters measured were heart rate, respiratory rate and ventilation, changes in body heat content and tolerance time.

7. bocal Body Cooling with a Water Perfused Cap B. Rappeport, A. Shots and M. Li titan

Evidence found in the literature suggests a significant portion of metabolic heat may be extracted through the head surface. The head's rich circulation, characterized by a low vasoconstrictor response to cold and the location of thermoregulatory centers suggested investigation of head cooling as a means of alleviating thermal stress. The geometric configuration of the head enabled the use of a rubber balloon to achieve close contact between the coolant and the head, hence improving the rate of heat dissipation. 72

PUBLICATIONS AND REPORTS

1. Arad, S. and А.Б. Richmond. Concerning the Effect of Hormones on RNase Activity. Eighth Meeting of FEBS, 1972.

2. Back, A., S. Bittner and A.E. Richmond. The Effect of Abscisic Acid on the Metabolism of Kinetin in Detached Leaves of Rumsx pulcher. Journal of Experimental Botany, 23, 76, 1972.

3. Bedrak, E., V. Samoiloff, U.A. Sod-Moriah and S. Goldberg. Synthesis of Androgens In Vitro by Testes of Rats Acclimatized to a Hot Environ- ment. Journal of Endocrinology, 51, 489, 1971.

4. Bedrak, E., V. Samoiloff and 2. Finkelstein. Testosterone Biosynthesis in the Desert Mouse Aoomys eahirinm. Journal of Endocrinology, 51, 7, 1971. 5. Bedrak, E., M. Ferck and N. Snapir. Evidence for Enzymes of Steroid Metabolism in the Bursa of Fdbrioiua. Comparative Biochemistry and Physiology, 38B, 4Ц, 1971.

6. Bedrak, E. Enzymes of Androgen Biosynthesis in the Desert Mouse - Gerbillua dasyurm. General and Comparative Endocrinology. (In Press).

7. Ben-Zioni, A. and C. Itai. Short and Long Term Effects on High (47-49°C) Temperatures on Tobacco Leaves< I. CO, Fixation. Physiologia Plantarum. (In Press).

8. Berlyne, G.M., R. Yagil, J. Ben-Ari and G.M. Danovitch. Aluminium Tox- icity in Rats. Lancet, 1, 464, 1972.

9. Berlyne, G.M., R. Yagil, J. Ben-Ari and G.M. Danovitch. Aluminium Tox- icity in Rats (c). Lancet, May 13, 1972; ,.

10. Berlyne, G.M. and M. Morag. Metabolic Effects of Drinking Brackish Water. Desalination, 10, 215, 1972. 73

11. Berlyne, G.M., J. Ben-Ari, M. Epstein, A. Booth and R. Yagil. The Rarity- of Renal Osteodystrophy in Israel Due to Low Phosphorus Up- take. A Natural Experiment. Nephron. (In Press). 12. Bracha, P., M. Luwisch and N. Shavit. Thiadiazols of Herbicidal Activity in "Pesticide Chemistry", (A. Tabori, Editor), 5, 141, 1971. 13. Degani, H. and N. Shavit. Ion Movements in Isolated Chloroplasts. III. Ionophore-Induced Ion Uptake and its Effect on Photophosphory- lation. Archives of Biochemistry and Biophysics, 152, 339, 1972. 14. Graziani, Y. and A. Livne. Water Fluxes and Permeability in Tobacco Leaf Tissue. Israel Journal of Botany, 20, 320, 1971. 15. Graziani, У. and A. Livne. Sterols and Water Permeability of Lipid Membranes. Israel Journal of Chemistry, 9, 25BC, 1971. 16. Graziani, Y. and A. Livne. Vasopressin and Water Permeability of Artificial Lipid Membranes. Biochemical and Biophysical Research Communications, 45, 321, 1971. 17. Graziani, Y. and A. Livne. Dehydration, Water Fluxes and Permeability of Tobacco Leaf Tissue. Plant Physiology, 48, 575, 1971. 18. Graziani, Y. and A. Livne. Water Permeability of Bilayer Lipid Mem- branes* Sterol-Lipid Interaction. Journal of Membrane Biology, 7, 275, 1972. 19. Graziani, Y. and A. Livne. Prostaglandin, Vasopressin and Water Permeability of Artificial Lipid Membranes. Israel Journal of Medical Science, 8, 1018, 1972. 20. Itai, с. and Y. Vaadia. Cytokinin Activity in Water-Stressed Shoots. Plant Physiology, 47, 87, 1971. 21. Kali, J., S. Amir and M. Morag. Effect of Removing Pups When Mating Lactating Rats at the Poet Partum Oestrous. Laboratory Animal», 5, 137, 1971. , 74

22. Kuiper, P.J.C., A. Livne and N. Meyerstein. Changes in Lipid Com- position and Osmotic Fragility of Erythrocytes of Hamster Induced by Heat Exposure. Biochimica et Biophysica Acta, 248, 300, 1971. 23. Lips, S.H., D. Kaplan and N. Roth-Bejerano. Studies in the Induc- tion of Nitrate Reductase by Nitrite. I. Bean Seed Cotyledons. Biochemical Journal. (In Press). 24. Litman, M. and E. Rappeport. Partial Body Cooling with Water Cooling Garment. Abstracts XIX International Congress of Aviation and Space Medicine, p. 68, Tel Aviv, 1971. 25. Livne, A. and У. Graziani. The Effect of Kinetin in Rehydration Rate of Tobacco Leaf Tissue. Israel Journal of Botany, 20, 330, 1971. 26. Livne, A. and У. Graziani. A Direct Effect of Vasopressin on Hater Permeability of Artificial Lipid Membranes. Israel Journal of Chemistry, 9, 34BC, 1971. 27. Livne, A. Water Stress and Plant Responses• Israel Journal of Botany, 20, 334, 1971. 26. Livne, A. and Y. Vaadia. Water Deficits and Hormone Relations in "Water Deficits and Plant Growth" (T.T. Kozlowsky, Editor), Vol. 3, Academic Press, N.Y., 1972. 23, Livne, A. and A. Raz. Erythrocyte Fragility and Potassium Efflux as Affected by Temperature and Hemolyzing Rate. FEBS Letters 16, 99, 1971. 30. Livne, A. and Y. Graziani. A Rapid Effect of Kinetin on Rehydration of Tobacco Leaf Tissue. Plant Physiology, 49, 124, 1971. 31. Livne, A. and Y. Graziani» Vaeopreesin, Prostaglandin and Hater Permeability of Artificial Lipid Membranes. Eighth Meeting of FEBS, 1972. 75

32. Livne, A., P.J.C. Kuiper and N. Meyerstein. Differential Effects of Lipids on the Osmotic Fragility of Hamster Erythrocytes. Biochimica et Biophysica Acta, 255, 744, 1972. 33. Livne, A., P.J.C. Kuiper and N. Meyerstein. Lipids and Stability of Erythrocytes. Israel Journal of Medical Science, 8, 1018, 1972.

34. Livne, A., S.W. Moses and P.J.C. Kuiper. Linolenoyl Sorbitol and Osmotic Fragility of Erythrocytes Affected by Hereditary Spherocytes. Israel Journal of Medical Science, 8, 1017, 1972.

35. Meyerstein, N. and Y. Cassuto. Red Cell Metabolism in Heat-Acclimated Hamsters in "Red Cell Structure and Metabolism". (B. Ramot, Editor). Proceedings of a Colloquium, August 1969. Academic Press, 1971.

36. Meyerstein, N. Osmotic Fragility: Interaction Between Red Cells and Plasma During Heat-Acclimation in Hamsters. Israel Journal of Medical Science, 7, 704, 1971.

37. Meyerstein, N. and У. Cassuto. Red Cell 2,3-Oiphosphoglycerate in Heat-Acclimated Hamsters. Comparative Biochemistry and Physiology, 41A, 297, 1972.

38. Meyerstein, N. Seasonal Changes in the Human Erythrocyte. Israel Journal of Medical Sciences, 8, 1018, 1972.

39. Milner-Nevo, A. Influence of Several Male Pollinations on the Quality of the Fruit of the SFAX Pistachio-Nut. October 1971. 2 pages. (An Interim Report). (In Hebrew). 40. Milner-Nevo, A. Follow-ups of Growing Pistachio Nuts in the Negev. November 1971, 20 pages. (An Intermediate Summary). (In Hebrew).

41. Milner-Nevo, A. Dormancy Breaking Treatments in Pistachio Nut Trees. December 1971, 5 pages. (In Hebrew).

42. Mizrahi, Y., A. Blumenfeld, S. Bittner and A.E. Richmond., The Abscisic Acid and Cytokinin Content of Leaves in Relation to Salinity and Rela- tive Humidity. Plant Physiology, 48, 752, 1971. 76

43. Mizrahi, Y., A. Blumenfeld and A.E. Richmond. The Role of Abscisic Acid and Salination in the Adaptive Response of Plants to Reduced Root Aeration. Plant and Cell Physiology, 13, 15, 1972.

44. Mizrahi, Y. and A.E. Richmond. Abscisic Acid and Mineral Dep- rivation. Plant Physiology. (In Press).

45. Mizrahi, Y. and A.E. Richmond. Mineral Deficiency and Abscisic Acid. Israel Journal of Botany, 21, 123, 1972.

46. Mizrahi, Y. and A.E. Richmond. Regulation of Plant Hater Relation- ship by Kinetin and Abscisic Acid. Israel Journal of Botany, 21, 123, 1972.

47. Mizrahi, Y. and A.E. Richmond. Hormonal Modification of Plant Response to Water Stress. Australian Journal of Biological Sciences, 25, 437, 1972.

48. Morag, M., J. Shani (Mishkinsky), F,G. Sulman and R. Yagil. The Effect c". Perphenazine on Mammary Development and Milk Yield in the Dairy Ewe. Journal of Endocrinology, 49, 351, 1971.

49. Morag, M. and D. Robertson Smith. The Effect of Two Synthetic Anti- coagulant Drugs (Coumarin and Inandione) in the Ewe. Research in Veterinary Science, 12, 2, 1971.

50. Morag, M. and D. Robertson Smith. Problems of Long-Term Jugular Can- nulation in the Ewe. Research in Veterinary Science, 12, 192, 1971.

51. Morag, M. and E. Eyal. Poet partum Conception in Lactating Awassi and East Friesian X Awassi Dairy Ewes. Journal of Agricultural Science, Cambridge, 77, 109, 1971.

52. Morag, M. and D. Robertson Smith. The Day to Day Variations in Certain Blood Values and in Blood Coagulation Tines of Healthy Ewes. Refuah Veterinarith. Vol. 28, 74, 1971.

53. Morag, M., A.A..Degen and F. Poplicker. The Reproductive Performance of German Mutton Merino Ewes in a Hot Arid Climate. Tiereucht U. Zuchtbiologie. (In Press).

> pr "V*rr f->-^fi— ч 77

54. Morag, M. and E. Rubin. Animal Production in the Desert. Invited Review Presented at the Sixth International Biometeorological Congress held at Noordwijk, The Netherlands, September, 1972. 55. Pasternak, D. and G.L. Wilson. Some Factors Responsible for Varying Effectiveness of Stomatal Closing Antitranspirants. Australian Journal of Experimental Agriculture and Animal H'isbandry, 11, 48, 1971. 56. Pasternak, D. and G.L. Wilson. After-Effects of Abnormal Night Temper- atures on Stomatal Behaviour and Photosynthesis of Sorghum. The Mew Phytologist, 71, 683, 1972. 57. Pasternak, D., M. Twersky and I. Borowitz. Irrigation of Wheat with Saline Water in the Negev Plateau. Hassadeh, 52, 1972 (In Press). 58. Rabi, Т., Y. Cassuto and A. Livne. Comparison of the Oxidative Potentials of Liver and Brown Fat Mitochondria» Israel Journal of Chemistry, 9, 34BC, 1971. 59. Rabi, Т., V. Cassuto and A. Livne. A Comparison of Oxidative Activity of Brown Fat and Liver Mitochondria in Hamster. Presented at Annual Symposium of Biochemistry in №1 Aviv, 1971.

60. Raz, A., A. Schurr and A. Livne. Effect of Cannabidiol (Hashish Com- ponent) in Human Red Blood Cells. Israel Journal of Chemistry, 9, 30BC, 1971.

61. Raz, A., A. Schurr and A. Livne. The Interaction of Hashish Compon- ents with Human Erythrocytes. Biochimica et Biophysica Acta, 274, 299, 1972. 62. Robertson Smith, p. and M. Morag. The Effect of Malayan Pit-Viper (Agkietroden rhodoatorra) Venom on Ovine Blood and the Development of Resistance to the Anticoagulant Activity of this Venom. Research in Veterinary Science, 13, 3, 1972. , , 78

63. Roth-Bejerano, N.. D. Koller and M. Ne$>i. Photoccntrol of Germination in Byoecyamus desertomm: Promotion by Light and Optimal Temperature, Induction of Inhibition by Light at Threshold Temperature and the Role of Gibberellin. Israel Journal of Botany, 20, 28, 1971. 64. Roth-Bejerano, N. and S.H. Lips. Induction of Nitrate Reduetase in Leaves of Barley in the Dark. New Phytology. (In Press).

65. Roth-Bejerano, N. and S.H. Lips. Induction of Nitrate Reductase in Leaves of Barley in the Dusk. New Phytology. (In Press).

66. Schurr, A., A. Hersovici and N. Shavit. Cannabidiol (Hashish Compon- ent): A New Ii-iibitor of the Photosynthetic Apparatus. Israel Journal of Chemistry, 9, 36BC, 1971. 67. Shavit, N. and V. Shoshan. Phosphorylation Coupled to Non-Cyclic Electron Flow in Photosystem I. FEBS Letters, 14, 265, 1971.

18 68. Shavit, N. Measurement of 32P«->ÄTP, ATP«-*H QH Exchange Reactions in "Methods of Enzymology" (A. San Pietro, Editor), 24B, 27, 1972. 69. Shavit, N. On the Interaction of ATP with the Energy Conservation Systems in "Chloroplasts" (G. Forti, M. Avron and A. Melancri, Editors). Proceedings of the Second International Congress on Photosynthesis Research, W. Junk, The Hauge, Vol. 3, 1972.

70. Shavit, N. On the Interaction of Nucleotides with the Chloroplast Mentorane and the Reconstitution of Phosphorylation. Sixth Inter- national Congress on Photobiology, Bochum, Germany, 1972. 71. Shoshan, S., S. Sprung, I. Bab and M. Litman. Hydroxyproline Excretion During Thermal Stress. Fifth'International Congress on Pharmacology/ Sari Francisco, July, 1972. 72. Shots, A. and M. Litman. Evaluation of Phy«iologic»l Strain During Heat and Work Stress. Twenty-Eighth Meeting of the Israel Physiol- ogical and Pharmacological Society, May 4, 1972.° 79

73. Shvartz, Б. and N. Meyerstein. Relation of Tilt Tolerance to Aerobic Capacity and Physical Characteristics. Aerospace Medicine, 43, 278, 1972.

74. Shvartz, Б. Natural Acclimatization to Severe Dry Heat. Aerospace Medicine. 43, 6, 637, 1972.

75. Shvartz, E. Efficiency and Effectiveness of Different Hater Cooled Suits - A Review. Aerospace Medicine, 43, 5, 488, 1972.

76. Sod-Moriah, U.A. Reproduction in the Heat-Acclimatized Female Rat as Affected by High Ambient Temperature. Journal of Reproductive Fertility, 26, 209, 1971.

77. Sod-Moriah, U.A. and R. Yagil. The Effect of Environment on Body Temperature in the Rat. Israel Journal of Medical Science, 8, 1009, 1972.

78. Sod-Moriah, U.A. The Effect of Chronic Exposure to High Ambient Temperature on Reproduction of Female Rats. International Journal of Biometeorology, 15, 92, 1971.

79. Sod-Moriah, U.A. Body Height and Composition, Oxygen and Food Con- sumption of Female Rats Chronic&lly Exposed to 35°C. International Journal of Biometeorology, 15, 93, 1971.

80. Tal, M. and Y. Nevo. Abnormal Stomatal Behavior and Root Resistance, and Hormonal Imbalance in Three Hilty Mutants of .Tomato. Biochemical Genetics, 8(3). (In Press).

81. Tal, M. and D. Imber. The Effect of Abscisic Acid on Stomatal Be- havior in Flaoaa, a Wilty Mutant of Tomato in Darkness. New Phytology, 71, 81, 1972.

82. Twersky, M. Factors of Chemical Fertilization in Saline Hater Irri- gation; A Review. Negev Institute for Arid Zone Research Publication, Beer Sheva, December 1971. 80

83. Twersky, M., D. Pasternak and I. Borowitz. Irrigation of Cotton with Saline Water in the Negev Plateau. Hassadeh, 52, 1173, 1972. (In Hebrew).

84. Twersky, M. and D. Pasternak. Irrigation of Agricultural Crops with Brackish Water at Mashabei Sade. Negev Institute for Arid Zone Research Publication, Beer Sheva, 1972. (In Hebrew). 85. Weinberger, G., R. Yagil, F. Poplicker and G.M. Berlyne. Aluminium Metabolism in the Uraemic Sat. In Proceedings Conference on Uraemia, University of Freiburg. (R. Kluthe and G.M. Berlyne, Editors), Ttiieae Verlag, 1971. 86. Yagil, R., z. Etzion and G.M. Berlyne. tte Effect of d-Aldosterone and Spironolactone on Sodium Reabsorption in the Lactating Rat Breast. Journal of Endocrinology. (In Press) . 81

DIVISION OF ENGINEERING SCIENCES

Head : К. Ргегвв 82

I. REVERSE OSMOSIS

1. Reverse Osmosis Desalination Plant, Yotvatah H. Cohen

The reverse osmosis desalination plant originally installed at Yotvatah in September 1968 was closed following tí»» collection, of the required experimental data. During the period of operation the E-398-10 cellulose acetate membranes originally installed were replaced by cellulose acetate type E-400-25, a more acetylated acetate with a higher viscosity. Following the replacement, operating pressure was reduced from 50 to 40 atmospheres. In the fall of 1970, the number of membrane failures increased rapidly over the average monthly failure rate. The large majority of these failures were due to deteriorating nylon cloth (used as wrap). During the past year it was found that the nylon cloth, used to wrap the cellulose acetate membranes could be destroyed by chlorine in the feed. Two assemblies using polyester wrap were installed in September 1970 to determine the effect of chlorine on this type of cloth. One assembly was removed after 2,700 hours high pressure operation (in March 1971) and found to be as strong as when originally installed. A second tube was checked after almost 5,000 hours and appeared as strong as the original. ; All the experimental data required was obtained during this period. The plant was finally shut down on June 30, 1971 and all major equipment dismantled and brought to the Negev Institute for storage. A final report was issued in January 1972. v Before plant closure, concentration polarization test» were made by Prof. Winograd and D. Levy. ; , 83

2. Reverse Osmosis Desalination Plants, Gilat and Abu Rhodes

H. Cohen

Small reverse osmosis desalination plants (15 m /day) have been successfully operated at Abu Rhodes and Gilat. During the period of this report, operation at both sites continued.

3. A Simplification in the Procedure of Fabricating Reverse Osmosis Membranes E. zisner and S. Loeb

It was found that Loeb-Sourirajan reverse osmosis membranes can be formed without heating if they are immersed in special electrolyte solutions rather than water. A large variety of electrolytes were tested and their influence on membrane properties studied. Performance (flux, desalination ratio) was highly dependent on electrolyte concentration and cations and anion size and valence.

4. The Recovery of Waste Water from Kitan Dimona Textile Plant V. Jamri and H. Cohen

The use of a reverse osmosis system to recover and recycle waste water from the Kitan Dimona Textile Plant was investigated. It was found that the overall waste stream would require extensive pretreatment if it were to constitute the feed for the reverse osmosis system. Therefore an inplant investigation was made to locate the largest operational wast* stream» and those which were causing the major contamination. It was found that the finishing machine cloth rinsing system was the major single user of water, about 300 m/day, all of which went to the overall waste stream. The stream from this unit was much cleaner than the overall stream. 84

Preliminary recycle tests made on the standard 3/4" pilot unit showed a reduction of COO from 460 to 60 ppm and a reduction of deter- gent from 4 ppm to less than 0.1 ppm. On the basis of these results a once through unit for use with the cloth rinsing system was erected at the Institute, with all necessary working tank piping and pumps, for transfer to the plant. Installation has been delayed pending completion of unrelated modifications in the wash flow pattern at the rinsing machine,

5. Survey in the Use of Pressure Driven Membranes in the Treatment of Industrial Waste streams S. Loeb and H. Cohen

A general survey of the use of both ultrafiltration (low pressure) and reverse osmosis (high pressure) membranes as a method for limiting pollution from industrial effluents has been initiated. Various preliminary tests on the standard 3/4" Negev Institute reverse osmosis unit have been undertaken on a recycle basis to study the rejection of various organic and inorganic compounds. Several types of ultrafiltration tubular membranes developed and fabricated in our laboratory were used. This work was done primarily to gain an insight into performance characteristics under controlled conditions.

A study was made of the effluents in the metal plating industry, mainly in the Tel Aviv area. Preliminary tests are being made on the 3/4" reverse osmosis unit on a recycle basis for the concentration and recovery for reuse of synthetic chromate rinse solution. Work is continuing. Preliminary tests are being made on the chemical effluent of a highly polluting stream from one of the main processes at an organic chemical factory. Only slight success can be expected because 1) high inorganic concentrations are present in the stream and 2) the organic» an all of low molecular weights and not well rejected in a low pressure system. 85

Preliminary tests have been performed on lignin solution, a waste product in the paper industry. In this case there is a good possibility that the inorganic salts can be separated from lignin, which might make the latter more amenable as an intermediate for production of valuable chemical compounds. This survey was started in conjunction with the Water Commission.

6. Reclamation of Municipal Waste Water R. Wechsler, A. Melamed and S. Loeb

The objective of this project is to reclaim municipal waste water to drinking standard. Six experimental systems employing pressure driven membranes (reverse osmosis and ultrafiltration), in conjunction with various pretreatment and post treatment operations will be investigated. In each system the pressure driven membrcnes are used to remove salt, organic solutes, and suspended matter. The pretreatment and post treatment operations are added to improve the effective membrane life or to polish the product.

It has been found that use of reverse osmosis membranes on raw sewage gave an unnecessarily good product, particularly in respect to salt removal. As a result, ultrafiltration membranes (low pressure) have been developed for sewage application. A new ultrafiltration membrane was developed which gives sufficient desalination for high recovery operations and rejection of dissolved solutes of molecular weights greater than 350. This membrane is currently being installed in a 2 m per day plant fed on raw sewage. 86

7. Performance of the Reverse Osmosis Plant at Yotvatah Under Various Hydrodynamic Conditions D. Levy, Y. Winograd (Technion, Haifa), N. Zelingher

Experimental data was obtained from a 200 a" /day reverse osmosis pilot plant operated at Yotvatah, in the Negev desert, using 57 millimeter 1.0. and 6 meter long tubular assemblies. Ibe data were used to characterize and verify (for this geometry) the existing equations which describe the performance of both the turbulent and laminar regions. Most results tended to support the theory for the turbulent region, although some discrepancies were found for the laminar region. An explanation for these discrepancies was presented.

8. Иге Shell and Tube Modular Concept in Reverse Osmosis

O. Levy and Su Loeb

The goal of this project is to develop at the Institute and test at an appropriate location a small Shell and Tube module which can prove the feasibility of single stage sea water desalination. A Shell and Tube module consists of a membrane mounted on the outside of a tube, several of which are installed within a pressure vessel, the shell. The pressurized brine flows within the shell and outside of the tubes. The desalinated water, which permeates the membrane, flows inside the tube and is collected outside the shell assembly. This geometry is rugged, lends itself to large scale production, and has the additional advantage that, due to the external location of the membrane skin, incipient macroecopic defects in the membrane skin tend to be closed rather than opened by pressure. This feature makes the Shell and Tube suitable for single stage sea water desalination. 87

Membrane formulations and manufacturing methods were developed, appropriate materials selected» and seals and turbulence promoters designed ana fabricated. A small 6 tube module was fabricated and tested with synthetic sea water. The flux varied between 0.2 and 0.3 m3/m2 day and the product salinity was about 1 g per liter. A discussion of work to date appeared as Division of Engineering Sciences Beport 125. Future work is to be concentrated on developing better membranes, testing at sea water sites, and possible testing of foreign modules.

9. improvement of Internal Tubular Modules 0. Levy and S. Loeb

Although the use of the tubular geometry is now considered limited in water desalination, it appears well suited for waste water treatment. Accordingly, continued development of the tubular configuration appears worthwhile. A system for heat treating the membranes in the casting tubes before their assembly has been designed and fabricated and will soon be tested. In the near future, methods to avoid membrane collapse will be considered, as well as the development of turbulence promoter*.

10. Development of Reverse Osmosis Membranes S. Loeb and M. Weintraub

Cellulose acetate butyrate membranes were made and tested. Better than 99 percent rejection of sodium chloride was obtained under conditions ' '• 3 2 of 50 atmospheres pressure and 5,000 ppm NaCl feed. Fluxes of 0.25 m /m day were obtained for membranes from a standard casting solution and 3 2 '' 0.35 m /ra day for those with pyridine in their casting solutions. The membranes did not have to be heat treated to achieve high salt rejection. Resistance to degradation at pH 10 was determined. The mechanical strength 8 ' ' - of these membranes was poor. Attempts at varying the casting solution to achieve better mechanical strength resulted in membranes of very poor flux. An unusual feature of the cellulose acetate butyrate membrane» was their high salt rejection (>|19O percent) when the reverse «ida of the auibran* faced the feed. \ 88

Cellulose acetate blend membranes made from a mixture of cellulose "diacetate" and cellulose "triacetace" were tested. Rejects of 97 percent 3 2 sodium chloride and fluxes of 0.32 m /m day were measured at feed concentrations of 9,000 ppm Had and 40 atmospheres pressure. Difficulty was encountered in duplicating casting solutions due to the insolubility of the "triacetate". 11. Development of Ultrafiltration Membranes S. Loeb and M. Weintraub

Ultrafiltration membranes of cellulose acetate were made up following the casting solution formulas reported by Van Oss. These membranes were characterized using pure solutes, and the effect of feed concentration and pressure on membrane performance was observed< At the standard working pressure of 2 atmospheres the CA 35 membrane rejected 95 percent of solutes with molecular weight 10,000, while rejecting only 14 percent of sucrose, molecular weight 342. CA 50 membranes rejected 92 percent of 20,000 molecular weight solutes and only 10 percent of solutes (Bacitracin} with a molecular weight of 1400. CA 75 membranes rejected only 2 percent of Bacitracin while rejecting 90 percent of Pepsin (molecular weight 35,000). The fluxes of these membranes were 0.7, 1.7 and 3.5 m /m day respectively, with water. Hie CA 100 membrane reported by Van Oss to pass serum albumin (M.W. 70,000) and reject y-Globulin (M.W. 160,000} could not be reproduced. A CA 25 membrane was made up and tested. Xt rejected 93 percent of sucrose and 14 percent sodium chloride while giving ¿luxes of 0.25 m3 /a t2 day. CA 50 membranes showed a linear increase of flux with pressure only to 3 atmospheres. At 3 ; atmospheres the flux increased to 2.5 v?/m day but the rejection of 20,000 molecular weight solutes dropped to 74 percent. CA 35 membranes showed linear increases of flux to 5 atmospheres, giving fluxes of 2.3 m /m day and 95 percent rejection of 20,000 molecular weight solutes.» \. ' • ,

•it ¡t~¿--* :&*:•"'К '••"".-,- 89

Keeping the pressure at 2 atmospheres but increasing the feed concentration from the standard 0.2 percent to 10 percent decreased the flux 3 2 3 2 of CA 50 membranes to 0.4 m /m day from 1.7 m /in day. The rejection of 20,000 molecular weight solutes dropped from 92 percent to 76 percent.

12. Reverse Osmosis Tubular Module with High Recovery Coefficient

N. Zelingher

A new concept to obtain a high recovery coefficient was developed. Theoretical consideration and the experimental results which confirm them show that an increase in bulk brine linear velocity reduces the product water salinity. Based on this fact it was proposed to increase the linear velocity at the end of the large tubular reverse osmosis plant by introducing a rod in the tubes. This reduces the cross-sectional area, thereby increasing the velocity, but the active surface of the membrane remains the same. Results of the experiments conducted with and without the rod confirm the concept. For a 40 m /day plant it is possible to increase the water recovery from 55 percent to 85 percent.

13. Reverse Osmosis Tubular Module - Noroograms

N. Zelingher

A set of nomograms for rapid calculation of some parameters involved in reverse osmosis tubular modules for which the tubes are in series were calculated and plotted. They ares

i. Nomogram for total pipe length,

ii. Nomogram for total cost of pipe. "'

iii. Nomogram for operating parameters. '. '"?

iv. Nomogram for maximum length of pipe for one modul*.

v. Nomogram for kinematic viscosity, diffusivity of salt and Schmidt number. ',••' " „ 90

vi. Nomogram for Reynolds number and Chilton Colburn mass transfer factor. 91

II. ELECTRGDIALYSIS

1. Dialysis with Polyethylene Meinbranes Б. Korngold

Thin, high density membranes were fabricated for use in calcium- sodium exchange. Sodi.ua chloride solutions ranging from 0.5-10 percent NaCl and sea water were used in the brine compartments of the electrodialysis stack. Water containing 800 to 1000 ppxu was used in the dialysis compartments. Calcium and magnesium ions passed to the brine compartments in exchange for sodium ions. It was found that about 60 percent of the hardness could be continuously removed. The results to date indicate that the exchange velocity was not markedly influenced by changes in the brine concentration. The exchange velocity increased with decreasing membrane thickness.

2. Development of Technology of Manufacturing Reinforced Membranes E. Korngold

A sulfochlorinated solution of polyethylene was cast on screens to obtain reinforced electrodialysis membranes. Various types of polyethylene screens were ussd. To obtain continuous membrane films on the screen, techniques of dipping, spraying and brushing were used. The last one appears to be the most promising at this time. The addition of ion exchange resin to the cast solution produced membranes with superior properties.

3. Development of Blectrodialysis to Obtain Water of Low Salinity B. Korngold

Electrodialysis is used to decrease the salinity of potable water from 800-1000 ppm to 50-100 ppm. The technique is useful for obtaining deionized water for various uses. An electrodialysis unit with а 6 в /day 92

capacity and a capability of producing water with 100 ppm salinity was built in our laboratories for the Volcani Institute. Hie unit is fully automatic and contains a softener to eliminate Ca and Hg from the water. A similar unit for 1.5 m /day has been in operation at the Negev Institute for several years. Polyethylene membranes manufactured at the Negev institute were used in both units.

4. Neutral Membranes for Transport Depletion Process Б. Korhgold

in the conventional process for the electrodialysis of water, serious scaling and fouling, caused by deposits on the anionic membrane, markedly reduce the effectiveness of the process. In order to minimize these effects, the water is generally pretreated before electrodialysis, usually by ion exchange. An alternate method involves the transport depletion process, wherein a neutral membrane such as cellophane is substituted for the anionic membrane. Cellophane membranes, however, are unstable at low pH and cannot be us@d when acid addition trsatssnts arc inelausd in the cycle.

A novel neutral membrane was developed which consists of a matrix of permselective polyethylene anionic membrane in which is embedded grains of a cation exchange resin, which decreases the permselectivity of the membrane. It is possible to prepare membranes of any desired degree of permselectivity in this manner by varying the ratio of embedded resin granules to matrix. Иге membranes thus produced have a lower electrical efficiency than that of typical anionic membranes used in electrodialysis. On the other hand, they exhibit a substantial decrease in scaling and fouling, eliminating the necessity to pretreat the water.

5. Mathematical Model for Engineering Design and Economic Evaluation of Elactrodialysis Plants - A Computer Method

. N. Zelingher . ' • " ,: '"'' ' ' :-

During the course of this study an engineering model was prepared which ia based on periodic technical information received from the design of the 93

Mashabei Sade project and on knowledge accumulated in the Negev Institute, especially from the operation of the Tzeelim pilot plant. The main task was to convert all technical data and engineering design relations into a mathematical model in a form suitable for computer calculation. The complete mathematical model was successfully tested on six different brackish water sources in Israel and the results have been presented in a detailed report. The work was done in collaboration with Dr. M. Avriel from the Technical, Haifa, J.R. Оlie, the Project Manager of the Mashabei Sade Plant and A. Raz from Mekoroth Water Company. 94

III. ION EXCHANGE

1. The DUCOL Process - Laboratory Demonstration of Feasibility

S. Evans

The DUCOL Process (S. Evans, E. Komgold, Patent Application 36445), a strong acid-weak base ion exchange system that incorporates lime slurry regeneration, was applied to brackish.water deslination. The use of lime regenerant results in a major cost advantage. The dollar cost per equiv- alent of conventional regenerants, such as sodium hydroxide and ammonia, are $2.64 and $1.11 respectively. The corresponding dollar cost per equiv- alent for lime is $0.29.

A 2 percent lime slurry was successfully used as the regenerant for the weak base resin. Based on 25 cycles of operation with a feed of 1600 ppm TDS, there was no fall-off in the capacity of the weak base resin. The cost advantage of using lime puts the strong acid-weak base system in a new perspective in terras of application to brackish water desalination,

A laboratory plant capable of treating between 1 and 3 m /day is now being set up.

2. The DUCOL Process - Removal of Nitrates

S. Evans

The DUCOL Process was studied with Beer Sheva tap water to which 70 mg/1 N0_" was added. An unusually high selectivity for nitrate was demonstrated in both a demineralization cycle and in a subsequent softening cycle. The preliminary cost estimate for water containing 14.5 meq/1 TOS (with 70 rag/1 NO, ) 3 л is in the range of 10 Ag/m . The product water differed from that produced by a softening process, (e.g., passing raw water through a column of strong base resin in the chloride form), in that the final TDS was lower, could be adjusted by blending, and did not contain undesirable cations. A report of the work has been prepared and submitted for publication. 95

3. Removal of Nitrates from Water

B. Korngold

Research involving the removal of nitrates from water by ion exchange was continued. Sea water was successfully used as the regenerant for the ion exchange material. Nitrate leakage was observed when high concentrations of sulfate were present in the water (above 2 meq/1). Nitrate leakage was also observed at low regeneration levels. The results obtained can be used as the basis for pilot plant operation. 96

IV. APPLICATIONS OF NUCLEAR RADIATION

1. Development of a Probe to Measure Density in a Bored Hole in Negev Loess by Gamma Ray Backscattering

K. Preiss and A. Lahat

During the year 1970 the development of this probe was completed. The probe was calibrated in the field by comparison with the sand replacement test, and proved to be at least as accurate as sand replacement.

During 1971 some progress was made in having this adapted as a routine test. It is hoped that this will be realized during 1972. The project was partially supported by the Ministry of Housing.

2. Measurement of Soil Moisture Under an Experimental Road near Kfar Ata

К. Preiss and A. Lahat

The Materials and Research Laboratory of the Public Works Department is conducting research on an experimental road in Kfar Ata. The radioisotope group at the Negev Institute is adapting the method of measuring soil moisture by neutrons to this particular site with its particular problems. This is not a standard procedure because of the accuracy required and the soil conditions in this case. The work continues with close cooperation at all levels between personnel of the Institute and the Public Works Department.

3. Temperature Coefficient of Photomultiplier Tubes

A. Lahat and N. Blankman

It is known that the gain of a photomultiplier tube changes with temperature. The magnitude of the change may be different for different tubes. In this project gain shift, defined as a percent change in the 97

amplitude of pulses from a Cs 137 source, using a Nal(Tl) crystal, is being measured for various tubes as a function of temperature. An electronic circuit is being constructed to eliminate this gain shift.

4. Theory and Experiment in Gamma Ray Scattering

K. Preiss and R. Livnat

The parameters which may influence backseat tering of gamma radiation by a material are the source energy, distance from the source to the point of interest on the material, and the density and chemical composition of the material. The influence of these factors on the maximum depth to which the radiation may be considered to penetrate, and on the radiation intensity emerging in the interval of interest, is not completely understood, but would be helpful for applications of gamma ray backscattering. The work continues by experiment and Monte Carlo calculation.

5. Measurement of Density Gradient in Cylindrical Specimens

R. Livnat

Apparatus which will measure density in cylindrical specimens by gamma ray transmission was built and calibrated. Some measurements were made on sand poured into a cylindrical mold as in the sand replacement teet. It is hoped that the apparatus and density measurement method will find application in concrete testing, as it has in other countries. During the year 1971 the work was completed and a report written.

6. Development of a Method of Nuclear Well Logging to Measure Chlorinity of an Aquifer

K. Preiss and A. Haccoun

Chlorinity of an aquifer can be measured with a nuclear probe from a borehole by several methods: measuring the difference between thermal and epithermal flux, measuring gamma radiation from the (n, y) reaction on ; 98

chlorine, or by measuring the decay of neutron or gamma activity following a neutron pulse. Laboratory investigations are being carried out on specimens with geometry, composition, and porosity resembling an aquifer around a borehole in order to find what order of magnitude of accuracy may be expected from each-of the first two methods described above. Work on the thermal/ epithermal method has been completed and now continues on the (n, y) method.

7. Development of Nuclear Well Logging Methods for Hydrology K. Preiss

Nuclear well logging methods could give more accurate and detailed information about hydrogeological parameters than they do at present. To achieve this will require a research effort covering both experimental and theoretical aspects. Such a program is being set up in cooperation with a number ox other research institutes in Israel.

8. Development of a Method to Measure Bitumen Content of Asphalt by Neutron Moderation K. Preiss and A. Kaisennan

•Che bitumen content of asphalt is presently measured by a process of extraction which requires 48 hours to perform, ttiis procedure gives information after the road is constructed and it can be used to penalize the con- tractor or to decide to rebuild the road but cannot influence work in progress. A method is being developed to measure bitumen content on hot asphalt, at the mixing plant, within a few minutes. 99

9. Measurement of the Bulk Density of Carnallite in the Evaporation Ponds at the Dead Sea Works K. Freiss, A. Kaiserman and R. Livnat

The method of gamma ray transmission was developed some years ago to measure the density of sediment on the ocean floor. The method was adopted so as to measure the bulk density and therefore the total mass of Carnallite in the evaporation ponds at the Dead Sea. Measurements were successfully made.

10. Measurement of Neutron Flux Distribution Around a Neutron Probe in Soil K. Preiss, A. Haccoun and G. Shani (Negev University'

It would be a great help to be able to calibrate a neutron moisture probe by calculation, rather than experiment. There are various calculations in the literature of the flux at the detector as a function of probe geometry and soil density, composition, and water content. The different calculations give different results. Measurements of neutron flux around a probe in media of various water content are being made with activation foils, so as to give experimental evidence to check the validity of the í various calculations. ' 100

V> MISCELLANEOUS

1. Closed Crop Production System

P ,E. Rappeport

Preliminary work continued on the design of a closed crop production system which would permit the condensing and reuse of water transpirated from the soil and leaf surfaces and the opfeimalization of various environmental parameters.

Preliminary designs for various sub-assemblies of the system were prepared, including a heat exchanger based on film flow between two thin, elastic к5ёшЬгаг»бэв Ksat transfer experiments are in progress; but no data is as yet available. 101

PUBLICATIONS, PATENTS AND REPORTS

1. Avriel, M. and N. Zelingher. A Computer Method for Engineering and Economic Evaluation of Electrodialysis Plants. Desalination, 10, 113, 1972.

2. Cohen, H. The Use of Pressure Driven Membranes as a Unit Operation in the Treatment of Industrial Waste Streams. Symposium on the Development Potential of Brackish Waters. Beitan Aharon. 1972.

3. Cohen, H. Reverse Osmosis Desalination Plant - Yotvatah; Summary of Field Experience. September 1968 - December 1970. Water Desal- ination Symposium. Ein Bokek. 1971.

4. Evans, S. and E. Komgold. DUCOL Ion Exchange Process. U.S. Patent Office Application Number 228,304. ,.

5. Evans, S. and R. Raiter. The DUCOL Process Laboratory Demonstration of Feasibility. Symposium on the Development Potential of Brackish Waters. Beitan Aharon. 1972.

6. Evans, S. The DUCOL Process: Removal of Nitrates. Water Pollution Control Federation. 1972.

7. Forgacs, C, N. Ishibashi, J. Leibovitz, J. Sinkovic and K.S. Spiegler. Polarization of Ion Exchange Membranes in Electrodialysis. Desalination, ; ; : 10, 181, 1972.> ;- \ ,- . -;. .-л''-- ;- ч^Ч /--у-] - ''V"i '' ' 8. Forgacs, C. The Napping of Faradaic Efficiencies in Large Electro- dialysis Units. Desalination, 10, 287,; 1972. " ,

9. Jamri, V., D. Bigio and S. Loeb. Performance of Foreign-Made Reverse Osmosis Modules, symposium on the Development Potential of Brackish Waters. Beitan Aharon. 1972.

10. Korngold, E. Prevention of Coiloidal-Fouling in Elactrodialyais by Chlorination. Desalination, 213, 1971. : л

f^^^tl 5^, ^; ^^jy 102

11. Korngoló, E. The Characterization of a Newly Developed Membrane for Transport Depletion. Water Desalination Symposium. Ein Bokek. March 1971. 12. Korngold, E, Concentration of Copper Solution by Electrodialysis. Proceedings of the Annual Meeting of the Israel Chemical Society, 1971. 13. Korngold, E. Water Desalination by Electrodialysis and Reverse Osmosis, Holland and Italy. Symposium on the Development Potential of Brackish Waters. Beitan Aharon. 1972. 14. Korngold, E. Removal of Nitrates from Potable Water by Ion Exchange. Water, Air and Soil Pollution. (In Press). 15. Korngold, E. Manufacturing and Testing Neutral Membranes far Transport Depletion. Report to National Council for Research and Development. 1972. 16. Korngold, E. The Removal of Sodium Chloride from "Ferrodex" by Electro- dialysis. Report to "Abie". 17. Korngold, E. Neutral Membrane. Israel Patent Application Number 38500, January 1972. 18. Korngold, E. and F. de Korbsy. Reinforced Cast Polyethylene Sulpho- chloride Based Permselective Membranes. Report to the National Council for Research and Development. 1972. 19. de Korösy, F. and E. Korngold. Preparing Ion Exchange Resins from Polyethylene by Sulphochlorination. Report to Ministry of Development. 1972. 20. lacey, R.E. and S. Loeb. Industrial Processing with Membranes. Wiley- Interscience, a Division of John Wiley and Sons, Inc., New York, 1972. 21. Levy, D., ü. Winograd and N. Zelingher. Performance of the Reverse ; Osmosis Plant: - Yotvatah Under Various Hydrodynamic Conditions. Departmental Report 124. 1972. 22. Levy, D. The Shell and Tube Modular Concept in Reverse Osraoeis. Departmental Report 125. 1972.

•i* v :ЩЩ6Щ 103

23. Livnat, R. Laboratory Measurement of Density Gradients in Sand by Means of Gamma Rays. Departmental Report. 1971 (Hebrew) . 24. Loeb, s. Recent Developments in Reverse Osmosis Desalination. Water Desalination Symposium» 1971. 25. Preiss, K, Checking of Cast-in-Place Concrete Piles by Nuclear Radi- ation Methods. British Journal of Non-Destructive Testing, Vol. 13, Number 3, May 1971. 26. Preiss, K. and R. Livnat. Note on the Behavior of Back Scattered Gamma Ray Photons in the Scattering Medium. Departmental Report 120. 1972. 104

DIVISION OF Bead : S. Bittnev 105

I. ORGANIC CHEMISTRY

1. Иге Development of Gas Chroroatographic Methods for the Quantitative Determination of Plant Hormones

S. Bittner and Z. Even-Chen

One of the main barriers to routine physiological and biochemical studies in the field of plant hormones is the absence of a quick and reliable analytical method for their quantitative determination. The objective of this project was the development of Gas Liquid Chromatography (GLC) methods for plant hormone analysis. Because of the minute quantities of hormones in plant tissue we decided to use the electron capture detector which has a sensitivity as high as 10 grams. Utilization of such a sensitive detector required preparation of special derivatives of the hormones, i.e. , those containing halogen substituents.

During the past year an analytical technqiue utilizing GLC has been successfully developed for the hormone indole acetic acid (IAA). We developed a new route of fractionating this hormone, followed by special Thin Layer Chromatography purification to the stage of GLC purity. Different halogenated derivatives of IAA were, synthesized and tested for GLC sensitivity; the compound with the highest sensitivity was found to be trichloro- ethyl ester of IAA. The method is now available for routine work and is suitable for the determination of IAA in any plant material in quantities as low as 20 picograms.

Work is now under way on the development of a similar method for cytokinin determination. 106

2. Structure-Function Relationship in the Cytokinins Series

S. Bittner, I. Kartoon and R. Katz

During the last year we continued our research on this subject with the aim of synthesizing analogs of the plant hormone cytokinin, which will show similar bioactivity or "antiactivity" and with higher resistance to bio- degradabiIi ty.

Many compounds were prepared and their biological activity evaluated by the soybean callus bioassay and the tobacco callus bioassay. Of special interest were the amino-oxy analogs of benzyladenine and of isopentylamino purine which show unusual biological activity. Research on this problem is continuing.

3. Polymers Carrying Plant Hormones

S. Bittner, L. Uziel and M.L. Kovalio

The object of this project was the synthesis of polymers carrying plant hormones with potential agricultural use. The polymers could be either synthetic or natural. The bond between the hormone and -the polymeric backbone could be amidie, estermic, or glucosidic, all of which could be slowly degraded in physiologic medium and release the active compound,

. The main advantages offered by such compounds would include:

a) avoidance of a quick and instantaneous reaction of the hormone; I

b) existence of a constant optimalized concentration of the hormone in vivo; and

c) reduction of the number of hormonal treatments.

During the past year prelroinary work was doné on several aspects of the problem. This work included preparation of active derivatives of ethyl- benzene and styrene and bridging them to cytokinins; bridging of synthetic cytokinins to starch, cellulose etc. and the preparation of roethacrylic men-; omers to which indole acetic acid is connected. 107

4. Preparation of Analogs of Abscisic Acid (ABA) M. Gorodetsky, S. Bittner and M.L. Kovalio

The purpose of this research is to prepare synthetic compounds that might have ABA-like activity in plants and higher resistance to decomposition in the field. In this research we shall concentrate on preparing derivatives of penta-dienoic acid where R is the variable.

COOH

As this research is only in its first stages we do not yet have any results. In the future we hope to widen the spectrum of the synthetic compounds with the hope that some might prove useful in treating plants under stress conditions. 108

Ion-Permselective Membranes from Cellulosic Materials A. Sliszer, E. Bandel and M. Flitman

The objective of this research was the development of cheaper ion permselective membranes by using cellulosic sheet as raw material. This project was virtually finished at the end of 1970. However a certain number of experiments remained to be done prior to writing the final report and filing a patent application on the polyethylene imine based cellulosic membranes. These were conducted within the framework of OSW Grant No. 14-01-0001-1734 and a patent application was filed by the U.S. Department of Interior in January 1972.

The technology which we developed is similar to known methods of textile and paper finishing. Therefore, the same equipment employed in these industries could be used for membrane preparation. In our opinion pressure dyeing apparatus with recirculation would be the most suitable because it requires smaller amounts of chemicals than a dyeing jigger, and the duration of the technological process could be reduced. Under present conditions, only parchment and kraft paper can be considered suitable rav materials because of their relative cheapness and because they can be purchased in all sizes and lengths. No suitable cellophane sheet is presently available on the <.

All chemicals used for membrane preparation are readily available at a relatively low price. The mechanical and electrochemical properties' of the membranes are íil good, and tests of desalination and lifetime properties gave good results. Dimensional stability and antifouling properties of the membranes are excellent. The roughly calculated prices for the finished product are very low when compared with those of commercially available membranes. 109

6. Chelating Resins for Heavy Metal Ions

A. sUszer, M. Flitman and M. Leon

The object of this research project was the synthesis of a new type of chelating resin. The resins were obtained by polycondensation, with the aid of a chemical reaction which has not yet been used till now for crosslinking. The most important feature of the crosslinking reaction is that the group used for crosslinking, and to obtain a tri-dimensional network, serves concomitantly as an essential part of tív¿ chelating moiety of the resins. Thus the resin contains no ballast groups, and consists only of the aromatic backbone and the chelate active moiety. Therefore the resins have very good chelating capacities as calculated on .a weight basis.

The synthesized resins were tested mainly for their copper capacities; 5-40 percent were achieved, depending upon conditions of the chelating reaction such as duration, temperature and pH-range. Some resins have also shown good chelating capacities in a strongly acid medium (pH 1-2), for example in de-coppering spent and pregnant solutions from the Timna Copper Works. There is a possibility of direct recovery of copper from the pregnant solution without the cementation process.

In addition to copper some of the resins were tested for their capacity .о chelate the following metal ions (the best capacities are given in brackets): uranium (19 percent), thorium (9 percent), gold (64 percent), silver (34 percent), lead (8 percent), chromium (2 percent), cobalt (2.6 percent), nickel (3.3 percent), mercury (20 percent) and manganese (2.7 percent).

More than one hundred resins having a great diversity of chelate-active moieties of the same type were synthesized during a one year research period. We are continuing the synthesis, testing and evaluating of these novel chelating resins. 110

7. Cellulose Based Membranes for Reverse Osmosis

A. Süszer, M. Flitman and M. Joseph

The object of this research project is to prepare novel reverse osmosis membranes from cellulosic sheet materials, such as cellophane, kraft paper, parchment paper and filtier paper. For this purpose the cellulosic raw material was treated with reactive compounds which can establish covalent bonds with cellulosic hydroxyl groups. In some experiments the crosslinking method was combined with a treatment for introducing bulky, polar functional groups into the crosslinked cellulosic material. The reason for this treatment was to diminish the pore size of the raw material in order to obtain salt rejection.

In spite of the fact that all raw materials tested, with the excep- tion of filter paper, stiowed a certain amount of salt rejection, even without any treatment, none of the membranes developed from our research work are satisfactory for desalination by reverse osmosis because of their low salt rejection and/or flux.

We chose cellulosic sheet as a raw material because it is available in many qualities and sizes, is fairly inexpensive, and can easily be modified by chemical treatment without losing its mechanical resistance and structure.

We had hoped to produce good membranes by crosslinking or by sub- stituting cellulosic hydroxyl groups. Neither of these methods proved satisfactory. Although salt rejection of a maximum of 53 percent was achieved, flux was only 5-25 percent of that shown by a good acetyl cellulose membrane.

The best results were obtained from membranes prepared by crosslinking with cyanuryl-chloride, then modifying with.' compounds containing polar functional groups. - These membranes produced maximum salt rejections but the flux was only about 0.1 m /m day. No results were obtained with polyethyleneimine or with chromium-fatty-acid complexes. Membrane raw materials with cyanoethylating agents, such as acrylonitrile and chloro- acrylonitrile have also produced unsatisfactory results.

•.•jas»-SUM Ill

In spite of these unsatisfactory results, we feel that better results could be achieved using the crosslinking after treatment technique, provided that a more suitable cellulosic raw material could be obtained in collaboration with a specialized paper mill.

8. Cast Reinforced Membranes from Sulphochlorinated Polyethylene containing No Resin Powder F. de Körbsy and E. Korngold

The object of this work is the preparation of membranes which will not change their dimensions in different solutions and still have the. good desal- inating properties of membranes made of polyethylene sheet.

Ten percent polyethylene was dissolved in trichloro-ethylene and sulphochlorinated under illumination in a stream of Cl, + SO, gases. The Cl :S0_ ratio and the reaction time was varied so that the material contained varying percentages of Cl and S. Fabrics made of polyethylene (Fyltis, France) were dipped into the solutions, usually twice. The dried, cast membranes could be either hydrolyzed or aminated with dimethylamino-propylamine and guatemized with CH.Br. In this state however, the membranes jelled too much and came off the fabric after a while. The membranes were kept in distilled water at 65°c as a lifetime test for this deterioration., The surfaces of the polyethylene fabrics were then sulphochlorinated in a short heterogenous photochemical reaction to ensure strong binding between the reinforcing screen and cast membranes. This, however, was not enough and it proved necessary to heat-treat the cast membranes in order to crosslink them. Xt was. found that 125-130°C and 3-16 hours heating in sulphochloride state stabilized the membranes sufficiently: they did not swell off during the lifetime test after hydrolysis or amination. The aminated membranes were less prone to swell to a jelly than those which are hydrolyzed. It is preferable to begin amination with a petrol ether .solution of the amine in order to prevent overheating during the first minutes of reaction. 112

йг« Koxngold found that hydrolyzed menbranes can also be crosslinked in the SO_H state by heat-treatment. The time necessary to achieve good results in this case was only about 2 hours at 130°C.

Among three French fabrics of the Fyltis series we prefer type No. CP. 25/30. The optimal composition of the casting polyethylene sulphochloride is not yet definitely determined but seems to be between 5-6 percent S and 10-15 percent Cl (analysed after hydrolysis).

The fabrics shrink up to 25 percent or more when heated/ so that they had to be preheated to 130°C for an hour before beginning work.

9. ion Exchange Resins from Sulphochlorinated Polyethylene

F. de Korosy and E. Korngold

The object of this work is to utilize the process evolved for perm- »electivé aentorsmse for making ion exchange resins, especially anion exchangers.

He adopted the áethod of Dr. Yagur (Weizmann Institute) for sulpho- chlorinating polyethylene suspensions in carbon tetrachloride in a stream of 01,. and SO, at low temperatures. The highest percentage of sulphur attained this way was about 10 percent, that is 3 mol/g. This is too low for good cation-exchange resins» but we.were unable to increase the percentage of sulphur* Cation exchange resins were prepared by ¿hydrolysis, but they 'swelled to 5-10 times, their dry volume. This «welling could be reduced to 2 times dry volume by heating before hydrolysis.

Anion exchange resins were prepared from the sulphochloride by amin*» ation with tetraethylene-pentjunine (TEPA) or dimethylamino propylamine. After amination they were quatamized with CH.Br in ethanol or in nitro- mathane.

In.general we did not reach stoichiometrie N:S ratios. With TIPA we obtained about »percent N and wi-ti» propylarón» about. 5 fWeeot. We never-succeeded in quatarnizing all four amin* nitrogens in ÜM ТСРД resin*. Thar* is only one active nitrogen per propy lamine rest in the second resin • Thus we did, not obtain capacities which were high enough to be comparable 113

with commercial resins. Since anionic polyethylene membranes show the best anti-fouling properties among all commercial membranes, we tried to use our best anionic resins for removing organic colloids from,solutions. Prelim- inary experiments showed clearly that our resins are able to remove relatively large amounts of húmate from aqueous solutions and can be regenerated by NaOH. Among commercial anionic resins only the "macro- reticular" resins are able to do this, and then to a lesser extent. It was possible to prepare very fine powder (finer than 300 mesh) ion exchange resins by this method. Such powder was then used successfully as an admixture to sulphochlorinated polyethylene solutions for preparing permselective and neutral polyethylene membranes.

10- Bimolecular Lipid Membranes F. de Korosy and M.F. Taboch

The object of this work was to prepare bimolecular membranes and to examine their electrochemical properties after adding compounds which enhance their conductivity. The lipid used was egg lecithin prepared in the laboratory. The apparatus was first of the Bangham type with a hole in a teflon sheet; later the type used by J. Graziani of our Institute was adapted to our purpose. In the latter case the mexrbrane is smeared on the cut end of a polyethylene tube under aqueous solutions. Solutions could be exchanged on one side of the membrane. The additive was tetrabutyl-ammonium chloride (Bud) ; it wa» «Matt to the aqueous phase. Results seem interesting but are difficult to reproduce . Initially we found that the resistance of ths msmbranes decreased by two orders of magnitude; the concentration potentials show a preferred transfer of "Bu " against Cl", and there was rectification between BuCl and 114

KC1 solutions. The sign of rectification showed preferred К transference» with conductivity ratios up to 1:4, The biionic potential also showed preferred К transference о In latter periods of the work, resistance decreased only by one order of magnitude and the rectification nearly disappeared» The concentration remained but seems to show a time dependence ending up with a preferred transfer of chloride, the biionic potential between "BuCl" and KC1 behaves in a similar manner: at first "Bu " passes the membrane but after a while the transfer of К becomes dominant as if the presence of "Bu " opened the membrane structure. The time necessary for this change can be shortened by introducing "Bu " with an electric current, and the change can be reversed by using a current to introduce К .

The (BUjN) Cl was at first prepared from a not very pure hydroxide and later on from a relatively impure Kodak (Bu.N)Cl by chromatography over SiO^, The difficulty in reproducing results is perhaps due to this impurity. Jo Grazxani kindly determined the effect of BuCl on osmotic water transport across lecithin membranes and found a decrease by a factor of 0.7. The work is being performed under a grant from the Bosch Foundation.

H» Ceramic Membranes for Reverse Osmosis F. de K&rosy

The purpose of this work was to introduce a dense microporous inorganic layer into the surface of a ceramic material and use this material for reverse osmosis. Thimble-like ceramic tubes were prepared, and an apparatus was built for using these tubes (after coating) in reverse osmosis at up to 50 atmospheres . 115

Two solutions were absorbed one after the other in the surface of the tubes and formed gel-like precipitates in it. Sodium silicate and different acids, and sodium silicate and metal salts are two examples. Only with precipitated cobalt silicate did we obtain/ at about 15 percent, salt rejection at normal flux rates. The desalination property was not permanent and could not be made to last. Sid. and organic RSiCl, compounds were absorbed alternately with ice-water in the surface of the tubes. The resulting silica gel layer gave up to about 30 percent desalination at normal fluxes, but we did not succeed in stabilizing this effect* The surfaces of the tubes were closed by smearing on enamels and melting silicates and firing to 1000-1200°C. The tubes were then attacked with strong acids to open them again. They opened very slowly but did not reject salt from solution. The work was supported in part by a grant from the Ford Foundation. 116

II. PHYSICAL CHEMISTRY

1. Specific Anodic Halogenation of Organic Compounds

T. Bejerano and Б. Gileadi (Tel Aviv University)

The project was divided into three main subjects:

a) Investigation of the anodic brominatioa reaction of phenol» The influence of the electrode material, electrode potential and reactant concentrations on the product distribution was studied. It has been shown that under certain conditions p-bromophenol or 2-4 di- bromophenol can be obtained at current efficiencies as high as 80-90 percent.

b) Bromination of alyl Alcohol.

c) Bromination of chlorobenzene.

The last two subjects will be studied as planned in the second half of the project.

2. Selective Inhibition of Electrode Reactions by Organic Compounds

T. Bejerano and E. Gileadi (Tel Aviv university)

The inhibition of different electrode reactions on Pt by phenol was studied-* It appeared that the effect is independent of charge or size of the reacting species.

The inhibition of I oxidation was observed when substituted phenols were used. A correlation seemed to exist between the ortho-para directing ability of the substitimit, its position with respect to the OH group, and the initial inhibition potential.

I 117

The possibility that polymer film is the primary cause of inhibition was eliminated by showing that 2,4,6-trimethylphenol - which cannot be poly- merized easily - inhibits the oxidation of I and of Bi.

3. Electrochemical Purification of Arad Phosphoric Acid

T. Bejerano, Б. Zeigerson and K. Gileadi (Tel Aviv university)

The purpose of this work was a} the development of a method for the production of bromide-free phosphoric acid, and b) the decolorization of raw Arad phosphoric acid. A method of oxidation of the bromide giving concentrations of 0.001 percent/ at high current densities of about 100 mA/cm , was developed* These current der sities remain constant during the process because it is possible to work at the potential of chloride oxidation. Current efficiencies of > 95 percent were obtained. The possibility of decolorization of raw Arad phosphoric acid by hydrogen-peroxide produced in situ at the cathode is now being investigated.

4. Bromination of.Organic Compounds by Electrolytically Generated Bromine

Б. Zeigerson, E. Gileacti (Tel Aviv university) and M.R. Bloch

The object of this work was a) production of electrolytically generated bromine from waste bromine solutions, and b) bromination of organic compounds by electrolytically generated bromine. The possibility of bromination of various organic compounds with electrolytically generated bromine was tested. It was found that natural polyphenöls which are by-products of the pulp and paper industry (ligno- sulphonates and basic lignins) are most suitable for producing bromo-organic compounds. The products, containing over 3C percent bonded bromine, act as effective flame retardante. In the industrial experiments performed in cooperation with "Kelet-Afikim", bromo-ligno-sulfonates (B.L.S.) and broso- lignins (B.It.) were found most effective as additives for producing flaps- proof pressed particle boards. • 118

possibility of using B.L.S. and B.L. to produce flame-proof paper, wood and plastic products is being investigated. To d?> this large amounts of B.L.S and B.L. will be produced on a pilot-plant scale, in cooperation with the Bromine Compounds Co. Investigations of the use of the spent crude lignin solutions from the sulfite and sulfate processes as raw materials for B.L.S. and B.L. production are being performed. Bromination reactions of synthetic poly-phenols are also being investigated in order to obtain new kinds of flame-retardants, especially bright coloured ones.

5. Production of Alumina From Ramon Clays

I. Eger

During the past year we continued our study on "Production of Alumina by Hydrochloric Acid". We also concluded research concerning the production of by-products such as concentrated HC1, SiO_ and Fe.O., A departmental report on this work was published.

During the period of the report we participated in the studies of A. Herz on the determination of the cost of producing alumina with acid as compared to alkali methods.

In addition, we concluded experimental research on the influence of salt (salt chlorides) on the extraction of Fed, by methyllisobuthyl-ketone. This work is in its last phase.

6. Production of CL, and MgO

1. Eger

A literature survey and preliminary experimentation were begun on production of &2 and MgO by thermal disintegration and oxygenation of dry carnallite. The results are satisfactory and the process; is definitely valid. Dr. С Forgacs is participating in the work and Dr. J. Epstein is acting a* advisor. 119

7. Timna's Copper Cement Purification

P. Gottlieb

The impure copper cement produced by Tirana may be purified as follows:

a) The cement is cleaned with a dilute sulfuric acid (1-5 percent) solution. The oxides dissolve, and the sulfate produced leaches the unreacted iron»

b) The wet cement is dried under a reducing atmosphere, then com- pacted by pressure and finally sintered at 900°C in a reducing atmosphere.

c) The sintared pellets are placed in perforated titanium baskets and subjected to an electro-refining process. The basketed pellets work as an anode and pure copper is obtained in cathodic plates of copper, stainless steel, or titanium.

The electrical consumption in the experimental works averages 0.5 Kwh per kg of cathodic copper.

With higher current density it is possible to obtain dendritic copper, but the electrical consumption is slightly higher (0.7-0.8 KwhAg) .

The spent electrolyte can be treated in two ways:

i) Bleed off the necessary volumes of spent cementation and replace it with a pure copper solution.

ii) Solvent extraction of the copper. When the solution's pH is between 1.5 and 2, a bromoiavic acid (I.M.I. Patent) or LIX solvents from General Milla can be used* Both processes are well known and give a vexy pure copper sulfate solution.

Previous economic calculation gives a process cost under Ь20 per ton of copper» 120

8о Use of "Ne gins t" Membranes for Obtaining Copper P. Gottlieb

A series of esqperiments to test the practicality of using Institute membranes (chlorosulphonated - cationic and anionic membranes) to obtain copper were performed» Яге "Neginst" membrane has given very good results, e.g., long life of the membranes, low voltage drop with the usual current densities (2 to 5 mA/cm ), and high electrical current efficiencies (more than 90 percent) .

9. Electrowinning of Copper from a Concentrate Solution of Na , Fe and Cu Chlorides Po Gottlieb

This work deploys "Neginst" permselective membranes for the electrowinning of cppper from concentrated solutions containing Na , Fe and Cu chloride о

Work has been done with anionic and cationic membranes of different thicknesses and electrical resistances.

After 10 months' work, all these membranes were stable, physically resistant, and gave good electrochemical efficiencies.

The only remaining problem is the development of a sack to put the anode in, and to give it some rigidity to avoid spilling and deformities which disturb the right deposition of copper»

10. Upgrading of &anganeae Minerals

P. Gottlieb

Experiments on the recovery of manganese from Tirana's ore (the ore itself or the tailing») were undertaken. They included» i a) Direct leaching with 20 percent HC1 (from Arad); 121

b) ¿eduction of the MnO2 to MnC, using coke fires as well aa reducing gases (GO), followed by leaching with HC1; and c) Leaching with appropriate solutions of ammocia and carbon dioxide.

The first procedure is going well, but the chlorine-gas developed represents a problem due to the pollution of the surrounding area. There- fore it is necessary to find an immediate use for the gas» The above problem is avoided by reducing the №0. to MnO, but iron is also dissolved. It can however be separated by oxidation and increasing the pH to 1-3.5.

The №*C12 obtained after purification may form HnO2 or metallic №, depending upon the electrolysis. With NH. and CO-, 15 to 18 moles and 3 to 5 moles respectively, the Mn"4"+ is dissolved and forms a complexo when this complex is filtered and heated to more than 55°C, MnCO. precipitates. Ammonia can be recovered by boiling the solution and all the Mn chemicals can be obtained from MnCO,. 122

III о ANALYTICAL CHEMISTRY

1. 4,4j Sulfonyl-bis-Azobenzene-di-Chromotropic Acid as Reagent for the Colorimetric Determination of Boron E, Szekely

The dye 4,4' sulfonyl-bis-azobenzene-di-chromotropic acid was obtainedо Many of the physico-chemical properties of this azo dye are similar to the chromotrope 2B, but it is a more sensitive boron reagent; as little as 0.02 ]ig boron can be detected in spot tests. Colorimetric determination can be performed in a range of 0.5-10 ppm boron samples.

The advantages of the reagent are its high sensitivity, color stability and the fact that the boron complex can also be formed in less concentrated sulfuric acid solutions„ This is especially important in the boron determination of soils and plants „

The method, developed by us in 1970, was applied in our laboratory in 1971.

2. Colorimetric Determination of Ammonia and Amino Nitrogen After Conversion to Nitrate

E. Szekely

Determination of ammonia or amino nitrogen was first investigated by Wo Leithe (Fresenius Z. An. Chenu 1970, 251(3), 185-6).

The principles of the described macro-method were applied on micro- scale о The oxidising procedure was simplified and the resulting nitrate determined spectrophotometrically using 4,4" sulfonyl-dianiline as reagent (Method E. Szekely, Talanta 1967, 14, 941-44). Some modifications were made in the original procedure, and an accuracy of ±0.5-1 percent was obtained. The method was applied inter alia for plant nutrient solutions containing ammonium nitrate.

q L 123

Both NO. and NH. were determined by this method. The method makes possible the determination of organic nitrogen after micro-Kjeldahl digestion without distilling.

3. A New Selective pH Indicator Е„ Szekely

A dye salt formed by interaction between isamine blue and thorine has been used for several years as pH indicator in our laboratory, particularly for the volumetric determination of sulfates. (This indicator developed by us was mentioned in our previous reports о) The isamine blue prepared from the cárcinogene 2-naphthylamine is no longer available„ Investigations were undertaken to find another component of arsenazo-

dye salt having similar properties» ; Several new indicators were investigated in our laboratory, and a sensitive, pH sensible indicator was prepared and tested. She results obtained were very satisfactory, and it is presently used for microsulfate determination instead of the thorine indicator.

4. Application of Existing Methods of Analysis in Which Modifications and Improvements Were Made E. Szekely

a) Determination of traces of bromine in phosphoric acid in the presence of chlorine The volumetric determination method (E. Szekely and J. Friedman, Xsr. J. Chem. 8, 1970), was used with some modification. largo amounts of chlorine do not interfere in the modified procedure. 124

b) .Determination of ircn and titanium and traces of chromium and manganese in fluoride complex samples

Sample solutions were treated with concentrated H2S04 and Excess acid was eliminated by evaporation and the resulting metal sulfates were used for all determinations» Iron determination. Titanium was hydrolized in acidic conditions and afterwards Fe was determined by EDTA titration using sulphosalicylic acid as indicator. The precipitated titanic acid does not interfere when using this procedure.

Titanium determination. Titanium was determined colorimetrically using H.O. as reagent. Modification was made in the method described by Sandell, Б.В. (Colorimetric Determination of Traces of Metals, 2nd Edition. Interscience, New York, London 1950, p. 571).

Iron does not interfere when the modified procedure is used. Beer's +4 Law is applied up to 120 ppm Ti when readings are undertaken at 410 nm. The precision of the method is ±1 percent.

Chromium determination. Chromium determination was performed in acidulated sample solution which was treated with KMnO.. The resulting hexavalent chromium was determined spectrophotometrically using diphenyl- carbazide as reagent.

Several modifications were made in the procedure described by Saltzman, B.B., (An. Chera. 1952, 24, 1016) to obtain greater simplicity and precision. As little as 4 yg Cr can be determined with a precision of ±0.5 percent when using the modified procedure. Beer's Law is applied up to 40 yg Cr.

c) Determination of traces of phosphorus

Trace* of phosphorus were determined speatrpphotoaetrically using an improved procedure of the molybdene blue method described in the ASTM Standard Methods» The method is applicable in a range of 0.1-2.5 ppm P when the readings are undertaken at 650 or 700 nm. The procedure is simple. Full color develops in 10 minutes.

**• '•-«- • 125

PUBLICATIONS, PATENTS AND REPORTS

lo Back, Ao, So Bittner, AOEO Richmond, So Ben-Joshua and N. Ahazbni. Elongation of the Shelf Life of Lettuce on Treatment with Plant Growth Substances. Final Report to the Board for Vegetable production. February 1972« 2, Bejer ano, To and E» Gileadio Electrochemical Bromination of Phenol. Proceedings of the Forty-First Annual Meeting of the Israel Chemical

Society, (p. g&ffo i?71*v 3o Bejerano, To and E. Gileadio Selective Inhibition of Electrode Re- actions by Organic Compounds» Journal of Electroanalytical Chemistry, 38, 137, 1972.

4о Bejerano, Т., Co Forgacs and E. Gileadio The Adsorption of Phenol and 2,4,6 Trimethylphenol on Platinum Electrodes« Journal of Electro- analyticfcl Chemistry, 1972 (In Press).

5о Bejerano, To, E» Zeigerson and E. Gileadio Electrochemical Purifi- cation of Arad Phosphoric Acide, Progress Report Ho. 1, January 1972 о

6о Bittner, So and M. Idelson. Solid-Stage Bromination of Mono-, Di- and Triphenols. Israel Journal of Chemistry, 1972 (in Press). 7. Bittner, S. ¿jfSiLZ.. Even-Chen. A New GLC Method for the Picogram Quantitative Identification of índole Acetic-Acid in Plant Extracts. Phytochemistry, Í972 (In Press). 8. Bittner, S, Preparation of Polymers Bearing Plant Hormones and Eval- uation for Possible Ose in Agriculture. Progress Report No. 1 to the Ministry of Developmentо January 1972. 10o Bloch, M.R., H. Fechtig, w. Gentner, G. Neukum and E. Schneider. Meteorite Impact Craters, Crater Simulations and .the Meteroid Flux in the Early Solar System. Proceedings of the Second Lunar Science Conference, 3, 2639, 1971. 126

11. Bloch, M.R., G< Neukum, Б. Schneider, A. Mehl, D. Storzer, G.A. Wagner and H. Fechtig. Lunar Craters and Exposure Ages Derived from Crater Statistics and Solar Flare Tracks. Third Lunar Science Conference, Lunar science Institute, Contribution No. 88,596. 12. Bloch, M.R. and W. Lücke. Hie Composition of Ocean Water Bubble Spray, Proceedings of the Symposium on Sea-to-Air-Chemistry (WORKSSAC), 1971. (in Press).

13. Bloch, M.R. and 0. Muller. An Alternative Model for the'Formation of iron Meteorites, Earth and Planetary Science Letters, 12, 1, 134, September 1971.

14. Bloch, M.R., A. Bodenheimer, J.A. Epstein and I. Schnerb. Prevention of Corrosion of Stainless Steel. Corrosion Science, 11, 453, 1971. 15. Bloch, M.R. Zur Entwicklung der von Salz abhangigen Technologien. Mitteilungen der List of Gesellschaft 7, 11, 253, 1971.

16. Bloch, M.R. She Roman Limes - A Fortified Line for the Taxation and Protection of the Salt Trade? Seventh International Congress on Roman Frontier Studies* Tel Áviv 1967.' Proceedings p. 186, 1971.

17. Bloch,, M.R. and W. Lucke. Geochemistry of Ocean Water Bubble Spray. Journal of Geophysical Research, 77, 27, 5100, September 1972.

18. Eger, Г. Carnallites A Survey, of the Literature. Negev Institute for Arid Zone Research Publication. 1972. i • i 19. Eger, I, and J.A.Epstein: A^O.-Manufacture from Maktesh-Ramon Flint Clays. Negev Institute for. Arid Zone Research Publication. 1972. .

20. Eger, I. and J.A. Epstein. Calcined Aluaina Via Hydrochloric Acid and Leaching and Iron Contraction. Cost Estimations by Andrei Here. Negev institute for Arid Zone Research Publication. January 1972.

21. Friedman, N., M. Gorodetsky and Y. Mazur. PhoftsSxidations of Olefins and Benzene Derivatives. Chemical Communication, 374, 1971. 127

22. Herz, A. Evaluation of Existing and Proposed Processes of Aluminium Sulfate Extraction from Clays. Negev Institute for Arid Zone Research Publication. 1971. 23. Herz, A. Preliminary Studies on Carnallite Processing. Negev Institute for Arid Zone Research Publication. 1972. 24. Korngold, E. and P. de Körosy. Experimental Reverse Osmosis Apparatus for Membranes in the External Surface-of Ceramic Tubes. Desalination, 11, 125, 1972. 25. de Körosy, F., A. Süszer, E. Korngold, M.F. Taboch, M. Flitman, E. Bandel and R. Rahav. Membrane Fouling and Studies on Electro- dialysis Membranes. Office of Saline Water, Progress Report Number 605. 26. de Körosy, F. and E. Zeigerson. Bipolar Membranes Made of a Single Polyethylene Sheet. Israel Journal of Chemistry, 9, 483, 1971. 27. de Körosy, F. Permeability of Liquids and Solutes Across Membranes. Ion Exchange and Membranes. To Appear in the First Issue of this New Journal. 28. Michaeli, I. and T. Bejerano. uptake of Salt by Polyacid Polybase Interacts. Journal of Electroanalytical Chemistry, 1971. 29. Savers, R.R., M. Gorodetsky, ¿.A. Whittle and C.K. Mu. Some Aspects of the Photochemical and Mass Spectral Behavior of Bridgehead Acetone Derivatives. Journal of American Chemical Society, 93, 5520, 1971. 30. Süszer, A. Cellulose Based Permselective Membranes. Negev Institute for Arid Zone Research Publication. 1971. 31. Süszer, A. Preparation of Anion Exchange Membranes from Cellulosic Sheets. U.S. Patent Application. January 1972. To United States Department of Interior. Patent granted in October 1972. 32. Süszer, A. Sulfonium Groups Containing Anion Pernselactiv* Membranes. To State of Israel. United states Patent Application, 1971. 128

33o Szekely, Б. Colorimetric Determination of Ammonia and Amino Nitrogen After Conversion tp Nitrate. Application of the Method for Organic Nitrogen. Proceedings of the Forty-First Annual Meeting of the Israel Chemical Society. (Abstract Page 14), 1971. 34. Szekely, E. 4,4' Sulfonyl-bis-azobenzene-dichromotropic Acid, A New Reagent for the Colorimetric Determination of Boron. Proceedings of the Forty-First Annual Meeting of the Israel Chemical Society. (Abstract Page 13), 1971.

35» Szekely, E., E. Bandel and M. Flitman. Volumetric Determination of Primary Arylamines and Nitrites, Using an Internal Indicator System. Talanta. 1972 (In Press).

36. Zeigerson, E. and E. Gileadi. Bromination of Organic Compounds by Blectrolytically Generated Bromine. Progress Reports (Quarterly), to the Ministry of Development.

37» Zeigerson, E. and E. Gileadi. Electrochemical Bromination of Organic Compounds. Proceedings of the Forty-First Meeting of the Israel Chemical Society, p. 264, 17, October 1971.

38. Zeigerson, E., M.R. В loch and №e State of Israel. Use of Brominated Lignin Sulfonate for Flame-Proofing and the Production of Flame-Proof Particle Boards. Israeli Patent Number 37812. 39. Zeigerson, E. Production of Bromo-Lignin Sulfonate, Economic Eval- ft' uation. June 1971.

40. Zeigerson, E., E. Gileadi and M.R. В loch. Bromination of Lignin Sul- fonate. Israeli Patent Number 37811. 129

THE LIBRARY

During the past year a reprint collection of articles written by the scientific staff presently at the Institute has been completed and arranged alphabetically by name of scientist» An SDI service has been started for the Reverse Osmosis and Ion Exchange groups in the Division of Engineering Sciences. This service is still in its initial, informal stage and is limited to current journals received in our library. The library has acquired a portable microfiche reader.

Statistics

Books 5743 Bound journals 4717 Current journals and serial subscriptions 474 Patents 410 Technical reports (non~cataloged) 1095 Interlibrary loans (Jan.-Dec. 1971) 1500

Publications Periodical holdings Bimonthly acquisitions list

Documentation services Retrospective literature searching Limited SDI

Staff Yaffa Glaseman, Head Librarian Miriam Michael!, Librarian Barbara Shivek, Librarian