THE ACCUMULATION OF SOME MIN Ok ELEMENTS IN COEN PLANTS
GROWN AT DIFFERENT LEVELS OF HYDROGEN-ION CONCENTRATION
Dissertation
Presented in Partial Fulfillment of the Requirements
for the Degree Doctor of Philosophy in the
Graduate School of The Ohio State
University
By
YUAN-PIN CHOU
The Ohio State University
1954
Approved byt ACKNOWLEDGMENTS
The author sincerely appreciates the help and guidance obtained from Dr. G. W. Volk, Chairman of the Department of Agronomy, Ohio
State University, who was instrumental in admitting the author to do graduate work in the Agronomy Department and in arranging the fellowship grant for this study.
Deep appreciation is due Dr. J. D. Sayre, Plant Physiologist,
U. S. D. A., under whose supervision this study was carried out.
Appreciation is also expressed to the Ohio Agricultural
Experiment Station for the various aids that made this work possible.
i TABLE OF CONTENTS
Page Introduction 1
Review of Literature 4
Experinental Methods 10
Method of Growing Corn 10
Method of Maintaining Constant pH 19
Radioactive Isotopes Used 21
Log of the Experiment 23
Method of Sampling and Autoradiographing 2tj
Procedure of Analysis 28
Experimental Results and Discussion 35
Experiment in 1951* Gravel Cultures 35
Experiment in 19521 Gravel and Solution Cultures 39
Experiment in 1953 61
Results from C o m Grown in Soils 61
Results of the Corn Grown at High and Low Concentrations of Minor Elements 70
General Discussion 76
Summary 84
Literature Cited 87
Appendix 93
Autobiography 116
ii THE ACCUMULATION OF SOME MINOR ELEMENTS IN CORN PLANTS
GROWN AT DIFFERENT LEVELS OF HYDROGEN -1 ON CONCENTRATION
INTRODUCTION
One hundred years ago, Carl Sprengel (59), a German agricul turalist, evaluated the ten mineral elements generally occurring in plant ash and concluded that they were all essential tor the growth of crop plants. In 1917, Robinson et al. (48) analysed a large number of plants from different regions and reported that 38 elements, mostly minor elements, were found in the plants. In 1950, Sayre (51), using radioactive antimony, wolfram, and iridium (which were not reported by Robinson ejt al.) in a nutrient solution for gravel culture, found that these three elements were all absorbed and accumulated in corn leaves. Jacobson at al. (27) found that a new chemical element, plutonium, could also be absorbed and translocated by plants.
Although plants may absorb any mineral element which is available in the medium, not all of the absorbed minerals are necessary for growth of plants. For instance, chlorine is universally present in plants, but it is not an essential element. Sodium is another element which is not essential for all plants, yet is always present in plant ash. Most of any mineral element absorbed by a plant, whether it is essential for plant growth or not, will remain in the plant, though some of it may move out. The distribution of the accumulation of each mineral element is different in different plants and in different parts of the same plant.
1 The location, pattern, and amount of accumulation of the mineral elements may shed light on the study of adequate fertilisation and of nutritional value, as well as of the diagnosis of the disease symptoms caused by the physiological disturbance. Since the begiflfling of the twentieth century, much work has been done on the subject of minor elements. Host of these studies involved attempts to prove that the elements were essential for plant growth. Studies of accumulation and distribution of minor elements in a whole plant have not been numerous, probably at least partially because of the laclc of quick and accurate means of determining them. Since the Atomic Energy Commission released the products of the atomic pile for research purposes, these isotopes have been used as tracers to study the accumulation of certain elements in plants. However, this method is limited to those elements which have isotopes available at the present time. The second best tool for studying the accumulation of minor elements in plants is probably the spectrograph, which is fairly accurate within the range of concentrations at which the mineral elements are generally found in plants. For this work, both radioactive isotopes and spectrographic techniques have been employed.
This study represents three years work (1951-1953) at the Ohio
Agricultural Experiment btation, Wooster, Ohio, on the accumulation
and distribution of some minor elements in corn plants in relation to
the hydrogen-ion concentration of the medium. In 1951, a preliminary experiment was performed using Zn®® in gravel cultures of corn. In
1952, Zn®^, Co®®, F e ^ , and brS® were used in both gravel and solution
2 cultures. The latter method was employed in order to provide uniform 6S 60 hydrogen-ion concentration around the roots. In 1953, Zn and Co were used in soil cultures in pots. In addition, corn samples from the field, from pot cultures, and from gravel cultures supplied with high and low concentrations of minor elements were analysed spectrographi- cally in order to get more information about the minor elements which were not available as radioactive isotopes. In all cases, radioactive materials were introduced at the tasselim; stage, and the corn harvested about one month later. No attempt was made to study the total amount of each element in the plant at different stages of growth. The relative concentration (micrograms of element per gram of dry plant tissue) was used to compare the accumulation of an element at different pH levels in each part of the corn plant.
3 REVIEW OF LITERATURE
The Recognition of Soae Minor Elements as Essential for Plant Growth
Sprengel (59) vas probably the first to maintain that the elements
generally found in plant ash, such as potassiun sodium, calcium,
magnesium, iron, aluminum, manganese, sulfur, and chlorine, were
essential for the groirth of plants* He further remarked that iron,
bromine, iodine, lithium, and copper, though occurring in minute
amounts, might also be necessary to the plants* However, not much
attention vas paid to his statement in the nineteenth century* Seventy years later, Maze, using water culture experiments with carefully
prepared culture vessels and nutrient salts, shoved that manganese,
zinc, boron, aluminum, and silicon were all essential in small amounts
for the healthy growth of the plant (33, 34, 35). His work stimulated
maqy other plant physiologists and aroused their interest in studying
minor elements with critical water cultures* The findings of Hase were
later confirmed ty the work of McHargue (36), Barnette and Warner (5),
Brenchley et al* (8), and Sommer (57). Sommer (58) also found that
addition of copper in low concentrations increased the growth of
sunflower, flax, and tomatoes, and demonstrated that copper was essential
for plant growth. The last element added to the group of essential minor elements was molybdenum. Araon and Stout (1) obtained evidence
that molybdenum was necessary for the growth of green plants.
Although cobalt has not been proven to be essential for plant
growth, it is required in the growth of animals, because cobalt is a
constituent of vitamin (46). Underwood anil Filner (61) found that
4 when sheep or cattle grazed on a pasture low in cobalt content, a mineral deficiency disease occurred which could be cured ty feeding several doses of cobalt nitrate*
Strontium is another element that has not been recognized as essential* However, McHargue (37) found significant yield increases of several grain crops when using a small amount of strontium carbonate in the presence of calcium carbonate, During recent years, strontium was found to be important in the bones of animals, because it stimulates deposition of calcium (49)*
The Accumulation of Some Minor Elements in Plants
Aluminum
Latshaw and Miller (31) reported that the amount of aluminum in different parts of a fully developed corn plant, expressed as percent of dry weight, was 0*07# in leaves, 0*013# in stems, 0*023# in grains,
0,052% in cobs, and 0*98# in roots, McLean and Gilbert (38) found in several species of plants the greatest accumulation of aluadnxn was in the cortex of the roots. It accumulated in the protoplasm rather than in the cell walls or vacuoles* Hoffer et al. (23, 24) reported that aluminum accumulated in the vascular region of the corn nodes, and related this accumulation to the root-rot disease. This was also suggested as one of the means of liagnosing phosphorus deficiency.
Boron
Boron has been reported ty several investigators to be more concentrated in the leaves than in the other parts of the plant (11,
41, 3). Boron toxicity is generally characterized by leaf injury which is More pronounced in the older leaves (64). The symptoms are yellowing of tips and Margins, often followed ty marginal or spotted turning. Milikan (39) investigated the toxic concentration of boron, and found that 2.5-12.5 p.p.e. excess of boron caused the death of older flax leaves but no chlorosis. Shive et al. (9, 45) reported that boron toxicity was progressively accentuated ty increasing the potassium concentration in nutrient substrates, but vas decreased ty increasing the calcium concentration. Jones and Scarseth (28) found that a high calcium concentration resulted in boron deficiency unless the boron concentration was also high. Gauch and Dugger (15) suggested that the role of boron in the plant might be the formation of an ionizable sugar-borate complex which would facilitate sugar translocation.
Calcium and Magnesium
Latshav and Miller (31) found that about 60% of the calcium in a fully developed c o m plant vas in the leaves, and only 4% in the grain and cob. Magnesium vas present in somewhat smaller amounts than calcium and distributed differently, the grains and the leaves each containing one third of the total magnesium. Ririe and Toth (47) reported that calcium was more concentrated in the upper leaves and lower stems of tomatoes, wheat, alfalfa, and red clover. It was localized in the outer edges of older leaves of wheat and alfalfa, and along the veins of alfalfa and red clover. Wadleich and Shive (62) found that the accumulation of calcium and magnesium in c o m plants was influenced very little ty pH values from 4 to 8. The effect of the
Ca/Mg ratio on the availability of minor elements was studied by Sanik
6 et al> (50)* They concluded that the maxima uptake of minor elements
ty wheat and sorghum, as well as maximum growth of these plants, seemed
to occur when the ratio of calcium to magnesium was 4 to 1.
Copper
Piper (42) reported that oats absorbed more copper at pH 4,0 and
4.7 than at pH 6*4, 7.5, and 8.6. Copper absorption was greatest in young plants and decreased as growth proceeded. The copper distribution
in oats harvested 193 days after planting was, in a decreasing order:
dead leaves, living leaves, straw, gram, and stems (67). It was
suggested that copper was relatively immobile in the leaves and was
not transported during later stages. In rice, copper was observed in
the cortical cells of roots, and accumulated near the root tips (25).
Cobalt
Fujimoto and Sherman (14) reported that in Hawaiian soils the
cobalt concentration was highest in the "A" horison, and seemed to parallel the accumulation of dehydrated iron oxide. But Hill et al.
(19) found that in New Jersey soils the cobalt concentration was
highest in the ttB* horison; it increased with decreasing particle sise, and was associated with ferromagnesium minerals. The exchangeable
cobalt in soils, like the other exchangeable bases, can be extracted ty neutral normal ammonium acetate (4). The solubility of cobalt is affected very little ty the presence of cations, but depends on the
anion used (69). Increasing available iron or manganese, or heavy application of lime or phosphate, was found to reduce the amount of
cobalt taken up ty a plant (6, 19).
7 Iron
Jones (29) reported that iron occurred in the chloroplasts and nuclei, and in large masses scattered throughout the cytoplasm. Boffer
(21), Hoffer and Carr (22), and Sayre (52) observed that iron accumulated in the nodes of corn plants grown in soils with high iron content or deficient in phosphate. Biddulph (7) found the greatest accumulation of iron in bean plants to be in the leaves and the least accumulation in the roots, when the Fe/V ratio in the substrate was one. The motility of iron in bean plants was retarded ty high iron or phosphorus concentration and ty high pH (43).
Manganese
Latshav and Hiller (31) reported that the manganese content of the c o m plant, expressed in percent of the dry weight, is about 0.017# of the stem, 0.037# of the grain, and 0.043# of the leaves. In maiy species of plants, it has been found that manganese accumulates more in the lower, older leaves than in the upper, younger leaves (26, 32, 40).
More mature plants appear to tolerate larger amounts of manganese.
Manganese accumulates in the margins and tips of the leaves, but not in the stem tissue. silicon
Latahaw and Miller (31) reported that the distribution of silicon in corn plants was 62#, 9#, and 1.5# in leaves, stems, and ears, respectively. Germar (16) found that silicon was deposited for the most part in the epidermis of the leaves of rye, wheat, and barley. A deficiency of nitrogen and an excess of potassium favored the
8 accumulation of silicon* Strontium
Although it occurs in plants only in trace amounts, strontium has been reported to be absorbed at about the same rate as calcium (10)•
Headen (17) found only 0.01/6 of strontium oxide in the crude ash of c o m leaves* Kediske and Selders (44) reported that strontium accumulated more in the lover and older leaves of soybeans* The absorption of strontium was proportional to its concentration in the nutrient solution up to 100 p*p.m* The ratio of strontium concentrations in leaves and roots increased linearly as the pH decreased*
Zinc
Since zinc can be fixed ty soils, plants may suffer from zinc deficiency while abundant zinc is still present in the soil (12, 18,
20) * Epstein and Stout (13) reported that an increase in tydrogen ion adsorption on clay particles increased the uptake of zinc by plants*
Williams and Moor (66) reported that the concentration of zinc in oats was 12,9 p*p*m. in the leaf, 8.3 p.p.m, in the stem, and 22.6 p*p.m*
n the grnin. Vood and Sibly {68) suggested that zinc was localized irr the chloroplasts, and was immobilized and not transported to other organs when the tissues were old (56). Shaw (55) found that zinc accumulated in the nodes of corn plants.
9 EXPERIMENTAL METHODS
Methods of Growing C o m m m m « m e n e m m Gravel Cultures
The c o m was grown in 3-gallon sloping-botton pots, with the sub-irrigating system as shown in Figures 1 and 2. Each pot held 15 kgm. of quarts gravel, of 3-4 nm diameter sixe. The gravel was washed with rain water before being used. A 5-gallon cau. boy painted with aluminum paint was used as a reservoir, arai 15.2 liters of nutrient solution made up for each culture. The nutrient solution was forced up into the pot with low air pressure from a smal 1 Crowell-type air pump.
The air pressure vas adjusted ty the micro ty-pass valves so that the culture was flooded within 15 minutes. Irrigation was controlled ty a time clock, and occurred five times daily at 9:00 A. H., 12:00 M.,
3:00 P. M*, 6:00 P. H., and 12:00 P. M. An additional irrigation was added between noon and 3:00 P. M. when the weather was hot.
The co^>osition of the nutrient solution used in these cultures is given in Table 1. Iron vas supplied ty adding about one spoonful of finely ground magnetite. The roots were aerated when the nutrient solution drained back into the reservoir. The minor elements were added in a mixture, the composition of which is given in Table 2.
In the sussner of 1953, c o m was grown in gravel cultures with low and high concentrations of seven minor elements. The low concentrations were obtained ty omission of the appropriate element from the minor element mixture, so that the only sources of the element were chemical inq>urities, pot walls, rain water, and air. The high concentrations,
1 0 . 3 A Klg. I < j , t . ^ -
r*i *t-e rr.
_V \
I ■'. /
-
{
B .3 1 t .1, ■I
f - i.n.1. ^ q i H i Vv'J
11 Table !• Coa^>osition of nutrient solution used in summers, 1951-1953.
P*B •a* in the Solution Salt Ma K Ea kg k(Wk4) P £ Ci
k h 2p o 4 13 10
KN03 69 25
\C1 38 35
Ga(NC-;) ry 100 7G •l <• >ia-SO. 29 :u
20 2 f
(>ill4)2S04 5 6
Total 29 120 100 20 95 5 10 52 35
Table 2• Minor element mixture.
Grams of Chemical Dissolved Salt in 16 1 of 0,1 N H2S0 4 P.p.m ♦
HgBOg 45.80 0.5
M n C l g - ^ O 29.00 0.5
ZnS04*71ioG 3.55 0.05
CuSO •5H2C 1.26 0.02
'(o g 3 0.28 0.01
r 4V'- 3 0.368 0.01
•i2Cr2ty7 C.905 0.03 \'iSC4*GIl3i 0.760 0.01
Co (MG3)2*6H2° 0.790 0.01 KaKG4*2H20 0.286 0.01
HO 2 0.267 0.01
12 which were supplied three weeks after planting, were as follows: iron,
12.5 p.p.*. (5i» iron citrate); manganese, 12.5 p.p.n.; boron, 12.5 p.p.*.; sine, 1.25 p.p.*.; copper, 0.2 p.p.*.; cobalt, 0.1 p.p.n*.; and molybdenum, 0.1 p.p.n. All the minor element concentrations, except boron, were tripled two weeks later; boron had already caused toxicity at that time.
Solution Cultures
Five-gallon wooden kegs were used for the solution cultures, as shown in Figures 3 axwl 4. The inside of each keg was painted with
"gravel cote." A piece of hardware cloth was fastened 4 inches below the top edge of the keg to separate the keg into two compartments. On the hardware cloth was placed a piece of plastic screen; this was covered with 2-*r inches of gravel, 3-4 mm in diameter, which was used to support the corn plants. The tube on the side was used to tell the depth of the solution inside the keg and also to sample the solution for pH determinations. Irrigation vas controlled by a mercury switch connected with a float in a 3-gallon pot. The solution was forced up into the keg with a low pressure air pump. When the solution rose to the gravel level, the mercury switch was opened and irrigation stopped.
Then the solution gradually drained back into the reservoir. When the solution had drained out of 2/3 of the keg, the mercujy switch was closed and irrigation started again. It took 15 minutes for one cycle of irrigation, 5 minutes for irrigating are! 10 minutes for draining.
«■ Parts per million of eleaient only when stock solution of the mixture added to nutrient solution at the rate of 1 ml. per liter of nutrient solution.
13 14 Fig* 4* C o m growing in solution cultures (1952)
Fig. 5. C o m growing in soil cultures (Aug. 24, 1953)
15 The aaKiunt of nutrient solution in each reservoir was 17 liters.
The solutions were the sane as those used for gravel cultures.
The iron vas supplied ty both magnetite and 5# ferric citrate. The latter was added at the rate of 0.5 al per liter of nutrient solution when the solution was replaced.
Soil Cultures
Pot Cultures
The soils for pot cultures were taken from the top 6-8 inches of
Wooster silt loasi, Mahoning silty clay loam, and Fincastle silt loan.
After the soil vas air-dried and passed through a 5-*m screen, an aswunt equivalent to 10 kgm. of oven-dried soil was weighed out, mixed with line and fertiliser, and placed into a 3-gallon glased pot. The amount of line to be used for adjusting the pH was determined from a lime requirement curve previously prepared. Fertiliser of analysis 10-10-10 was added at the rate of 500 pounds per acre. The soil in each pot was moistened with rain water, and the pots were left in the greenhouse for two weeks before the corn was planted in order to allow the soil to reach equilibrium. When the corn was small, the soil moisture was kept near field capacity ty weighing the pots twice a week and adding water.
Beginning one month after the corn vas planted, 400 ml of rain water was added to each pot two or three times per week. Figure 5 shows the c o m growing in pot cultures. Descriptions of the three soils used for pot cultures are given in Tables 3a and 3b.
Field C o m
W64 c o m was planted in two soil-testing plots at the Snyder farm
16 Table 3a. Description oi the soils.
Lime Requirement Moisture to pH 6.5 and 7.5 Parent Original Equivalent (Ca(0H)2 , ton/A) Locality Soil Type Material pH (%) 6.5 7.5
Wooster silt loan Snyder iarm glacial 5.4 22.0 1.8 5.8 0. A. E. S. sandstone Wooster, Ohio and shale
Mahoning siltv clav loam Lorain County glacial 5.4 24.6 1.5 4.0 Ohio sandstone and shale
Fincastle silt loan Campbell Far* calcareous 5.5 25.4 1.0 3.0 Warren County glacial Oh i o drift
F o s t e r silt loam Snyder larm glacial 5.8 (plot 6) 0. A. E, b. sandstone Wooster, Ohio and shale
Wooster silt loam Snyder Farm glacial 6.7 (plot 7) 0. A. E. S. sandstone Wooster, Ohio and shale Table 3b, Fertility of the soils.
Total exchange Organic capacity, Total Readily K Ca Matter m.e. per N soluble P a.e. per m.e. per m.e. per Soil Type (a) 100 soil (%) (P205 lbs./A) 100 g soil 100 g soil 100 g soil
Wooster silt loan 1.64 8.32 0.093 30 0.22 4.30 1.43
Mahonin., silty clay 2.6b 12.34 0.145 42 0,28 1.47 1.02 loan
tincastle silt loam 2.44 8.68 0.128 39 0.27 4.05 1.37
iooster silt loan 1.92 8.75 0.109 85 0.25 10.1 1.47 (plot 6)
«i>oster silt loan 1.90 8.42 0.108 130 0.24 10.8 1.74 of the Ohio Agricultural Experiment Station, Wooster, Ohio. These two
plots have been adjusted to pH 6*8 and pH 5.7 for more than 25 years.
Alfalfa vas grown on both the previous year. This year, no fertiliser
vas applied. The fertility of the two plots is given in Table 3b.
After the corn tasselled, three stalks taken at random from each plot
were used for analysis*
Method of Mai ntaining Constant pH
The NOg/NH^ ratio method suggested ty Trelease and Trelease (6C)
was used to hold the pH levels of the nutrient solutions reasonably
constant. Preliminary work showed that merely ty changing the W03/NH4
ratio the desired pH could not be maintained long enough for the
experiment, so appropriate amounts of 1 M or 1 M KOH (1 M NaOH was
used in 1953) had to be added from time to time. In 1951, a NO^/HH^
ratio of 95/5 was used for pH 8.5, and 70/30 for pH 5.5. Three pH
ranges were used in 1952 for both gravel and solution cultures:
7.5-7.0, 6.0-5.5, and 4.5-4.0. Efforts were made to keep the pH as
close as possible to 7.0, 5.5, and 4.0. The ratios of WO^/hH^ used for
these three pH ranges in 1952 were 95/5, 70/30, anti 50/50, respectively.
In 1953, the same three pH ranges were used, and the NC^/NTH^ ratios ur.ed
were 95/3, 80/20, and 65/35, respecIive ly ,
The pH of the nutrient solution vas checked and adjusted at least
twice each day from about a week before the radioactive materials were added until the corn vas harvested. All the pH determinations were made with a Beckman glass electrode pH meter, Model H. The average daily pH values of the solutions during the experimental period in 1951
19 are shown in Table 4.
Table 4. Daily average pH values of the nutrient solutions during the period of growth with in the gravel cultures (1951)*
pH of not 2 pH of pot 5 Date (NOgyAiH^ - 95/5) (N03/)JH4 - 70/30)
7-3C 6.3 5.4 7-31 6.4 5.3 8-1 6.5 5.2 8-2 6.6 5.6 P— 2 6.6 5.4 c . ftt 6.7 5.2 t - Z 6.7 5.4 B-C 6.6 5.5 8-7 6.6 5.4 8-8 6.7 5.4 8-3 6.7 5.3 8-10 6.7 5.5 8-11 6.6 5.3 8-12 6.7 5.4 8-10 6.8 5.5 o-1 4 6.7 5.6 8-10 6.6 5.6 8-1G 6.8 5.5 8-17 6.7 4*1 (lowered 8-2C 6.8 4*2 purposely) 8-21 6.5 4.0 P—2° 6.4 4,0 iC ') 6.3 3.9 8-21 b.5 4.0 OC — *■ 6.5 4.0 f>« — — i 6.3 ■1.0 8-2P 6.4 4.0 8-2? 6.4 4.0 8-8L 6.5 3.9
The original pH of the soils used for pot cultures was about 5.5
Two additional pH levels, 6.5 and 7.5, were made ty adding lime to th< original soils. PH was checked throughout the e;xper ament, and the values (average of 6 pots) are given in Table 5. Since the field plo have been adjusted to pH 6.8 and pH 5.7 for more than 25 years, no
20 Table 5* PH of the soil cultures during the growth of the plants. (Each figure is the average of six pots.)
Soil: Wooster Mahoning Fincastle desired pH: silt loasi silty clay lean silt loan Date 775— r a — 5 3 7~.r r.r— 53 73— ra— f-23-53 7.8 6.5 5.4 7.7 6.1 5.0 7.9 6.3 5.4
6-25-53 8.1 6.5 5.3 7.6 5.8 4.6 7.7 6.0 3.4
7.7 6.5 5.3 7.2 5.5 4.5 7.6 r-.o 5.4
S 1 ' - 1 ' *■* » 7.9 6.6 5.4 - ♦ . 6 4.7 6.9 * • 1 r,.f
.. 7.6 6.5 5.4 * • .6 4.7 6.7 5.3 4.8
-1 ••• ■ 7.6 6.5 5.5 .7 3.6 4.7 6.7 fS > • wr\ 4.7
treatment was required.
Radioactive Isotopes Used
The radioactive isotopes were obtained from the Oak Ridge National laboratories, Oak Ridge, Tennessee. Since only small quantities of the isotopes were obtained, they were usually diluted to 250 ml with
listilled water. Appropriate amounts of these dilute.! solutions wer’ used for the experiments. The characteristics of the isotopes and tY record of their use are given in Table 6.
The method of calculating the weight of the radioactive element
'Yon the carrier mixture and the radioactivity at a desired t law- is shown in the following example: The radioactive line used in 1951 was assayed on July 7, 195(J, as 4*0 rac of Zn65Cl2 . Since Zn^;> was produced
bombarding with neutrons, the zinc in the solution was a
rf* r j /jc fixture of 2n and 7,n 4. tOiat was the weight of Zn ° which produced the radioactivity of 4.0 me’ How much was the radioactivity of th<* Table P. The radioactive isotopes i.-ciV in 1951-1955.
->reci fic Amount used, me Chemical Half fcadiati on Date act ivity Mode of Decay Tate Element F*'*' form life of rays assayed me /mg. production product
7-30-61 Zn65 0.136 me Zn65Cl2 250 Y >K 7-7-50 0.175 Zn64( n O Z n 65 Cu65 (0.37 x 10*4 ) days
7-25-52 Zn65 0.60 me Zn65Cl2 250 / 7-18-52 0.022 Zn64(nv)Zn65 cu«5 8-7-52 (0.76 x 10*4 ) days
n160 7-25-52 Co«° 0.51 me Cofi0Cl2 5.2 V ’ /? 4-27-51 0.45 Co59(nOCo60 8-7-52 (0.75 x 10"4) yrs. y S O 7-25-52 Sr89 0.96 me 5r89Cl2 53 3 4-10-52 carrier fission (short 8-7-52 (0.36) days free product life) 8-6-52 U 55 0.35 me le55Cl3 2.91 K 7-18-52 0.819 Ke^4 (n r)!e5^ Mn(?) 8-7-52 (1.44 x 10*4 > yrs.
8-26-53 z„65 1.0 me 0 Zn65Cl2 250 f ,K 7-2-53 0.231 Z n ^ n r ) Cu85 (0.124 x 10““) days
8-26-53 Co60 0.9 me 5.2 7-3-53 4.091 l,i$0 Co 50C12 r ’ a Co59 (nr) Co60 (0.131 x 10“3) yrs.
* (mg.) means milligrams of pure radioactive element used. **■ The first date is for the gravel cultures, the second for the solution cultures. same radioactive material on July 30, 1951’
The half life of Zp ®^ is 250 days, which means the disintegration . 0 * 693 q -i constant ,-%(>•- life has value 3-21 x 10 sec" . As calculated ty using the Loschmidt number, 6,019 x 1023, 1*0 mg of contains 9*26 x liA® atoms. Therefore, 1*0 mg of Zn®^ will give rise to 9.26 x 10^® x 3.21 x 10"® or 29*72 x lO1^ disintegrations per second, fj Since 1.0 rac has 3*7 x 10 disintegrations per second, 4.0 me will correspond to (-■ * ■* 2^ ) mg or 0.49S x 1C"3 mg of Zn®5. 29.72 x 101G The radioactivity of the same material on July 30, 1951, can be calculated from the following equation. .t-t0 ct0 ct x 2 rh Ct “ count at t time (July 7, 1950) o ■ count at t time (July 30, 1961)
T; • half life (260 days) 3 OF 4 » X 27317
X = 1.3^'
Therefore, on July 7, 1950, the Zn®° solution had a radioactivity
*f 4.0 me. But on July 30, 1951, its radioactivity was reduced to Cr 1.364 me, which corresponds to 0.17 x 10“" mg of 2n .
Log of the Kxperi niont
Lxper.jjnent in 1951
May 2 4 Four seeds of W64 were planted in each gravel culture outdoors. Irrigation -ras started with rain water.
'one 5 Mutrient solution was added; this was replaced once every two weeks thereafter.
June 75 Seedlings were thinned to one plant per pot.
23 July 15 Flrom this date on, the pH was regulated ty the ratio method, and the solution was replaced once a week*
July 30 25 ml of Zn Cl stock solution, equivalent to 0*130 me, was added to each of two pots in which the pH values were 6*5 and 5.5. Subsequently, the solution was not replaced, but the sane nutrient solution was added once or twice a week.
August 6 Sampling of leaves for autoradiographs waa begun.
August 17 The solution of pH 5.6 was changed to pH 4 and kept at this pH until the c o m was harvested.
August 31 C o m plants were harvested.
Experiment in 1952
Gravel Cultures
June 6 Four seeds of W64 were planted and irrigation was started with rain water. The cultures were outdoors*
June 13 Seeds germinated in all pots.
June 20 Seedlings were thinned to two plants per pot. Irrigation with nutrient solution was begun*
June 30 Seedlings were thinned to one plant per pot. Nutrient solution was changed*
July 21 C o m tasselled* Use of nutrient solutions at 3 pH levels was started*
July 25 Zn 65 Co^, and Srn.HI were added to the solutions ir 0 pots (3 pots for each element)*
July 31 Sany ling of leaves for autoradiographs was begun.
\ugust C was added to the solution in two pots.
August 20 The corn plants grown with Zn , Co60 and Sr were harvested.
August 22 The c o m plants grown with Fe'*' were harvested.
Solution Cultures
June 24 W64 seeds were planted in 12 kegs inside the greenhouse*
24 June 28 Seeds germinated in all kegs*
July 1 Seedlings were thinned to two plants per keg* Irrigation with nutrient solution was begun.
July 7 Use of mercury switch for irrigation was started.
July 18 Upper leaves of the plants were yellowish. Use of ferric citrate in the nutrient solution was begun.
July 28 Irrigation with nutrient solution at 3 pH levels was begun.
August 3 C o m plants tassel led.
August 6 Sr®^, Zn®®, Co®®, and Fe®® were added to the solution.
August 7 Co®® and Sr®^ could be readily detected in the plants, Zn®® was weak, and Fe^S could not be detected*
August 8 Sampling of leaves for autoradiographs was begun*
August 23 All the c o m plants were harvested.
Experiment in 1953
Pot Cultures
June 26 Two varieties of com, K14 and K24, were planted in three types of soil at three pH levels* Each treatment was done in triplicate* Five seeds were planted in each pot* The pots were randomly set inside the greenhouse* Hie moisture was kept near the field capacity ty weighing the pots twice a week and adding water*
July 1 Seeds germinated. Germination was almost 30C$.
Julyr 6 Seedlings were thinned to one plant per pot.
July 13 Maiy c o m plants had phosphorus deficiency symptoms. 10-10-10 fertilizer was added in solution form at the rate of 300 lbs* per aero. All pots were moved outdoors* Each pot was covered with aluminum foil to prevent rain fall inf' into the pot and also to reduce evaporation from the soil.
July 27 Although no water had been added since July 13, all the plants had recovered and appeared very heal tty except those in three pots of Wooster soil at pH 7*5* Almost all c o m plants grown at pH 5.5 were taller than those grown at the other two pH levels-
25 July 27 Prom this date on, 400 ml of water was added to eacv! pot 7 or 3 tines a week, depending on the weather.
\ugust 22 Some plants had phosphorus deficiency symptoms again; other plants sensed to have potassium or nitrogen deficiency symptoms. Many lower leaves were fired even though the soils were moist enough. C o m plants at pH 6.5 were taller than those at pH 5.5.
‘ugust 2f Co®® was added to three pots, and Zn**1*65 to three pots, of K24 grown in Wooster soil.
August 28 All the corn plants, except those in the six pots to which Co®® and Zn®^ had been added, were harvested*
■>ept. 14 Hie plants in the six pots with Co®® and Zn®® were harvested*
Gravel Cultures Treated with High and Low Levels of Minor Elements
July 28 Four seeds of K24 were planted in each pot inside the greenhouse*
August 6 Nutrient solution was added* There were 15 minor element treatments at 3 pH levels* Each treatment was duplicated so the total number of pots was 90. For the lower level, no minor elements were added* For the higher level, only a normal amount of the minor element mixture was used*
August 18 The solution was replaced. For the higher level, the minor elements were added as follows: iron, 12.5 p.p.m.; manganese, 12*5 p.p.m.; boron, 12*5 p.p.m.; zinc, 1.25 p.p.m.; copper, 0*2 p.p.m.; cobalt, 0*1 p.p.m.; and molybdenum, 0.1 p *p *xn •
August 26 Boron toxicity systems were observed.
August 31 The solution was replaced. For the higher level, the concentrations of all minor elements except boron were tripled.
■:ept, li All c o m plants were harvested.
Method of Sampling and Autoradiographing
Autoradiographs were made for the following three objectives:
(1) to conpare the accumulations of the radioactive elements in upper and lower leaves, and at different pH levels; (2) to conpare the
26 accumulation of each element at different times* and (3) to coiqpare
the distributions of various elements in the whole plant* For the first
two ccnqparisons, two perfect leaves were chosen for sampling, one near
the top and the other near the bottom* The saaples were taken in small sections from half of the leaf blade. Three or four sections were
taken from one side of the leaf at an interval of 5, 8, or 10 days.
For the second conparison, loaf sanples were also taken as discs, with a punch, at intervals of 5 days, Fcr the third comparison, and for
tlte samples of stem, husk, cob, grain, etc., the sampling had to be done after the corn plants were harvested.
The sasples were placed between dry papers in a press and left there until dry. They were then cemented on a sheet of paper with latex glue and mounted on a sheet of type K X-ray film in a metal cassette.
The autoradiographs were produced ty direct contact, the exposure time depending on the amount of radioactivity in the samples.
The exposed X-ray film was developed with D19 developer at 68* F.
for four and one-fourth minutes, fixed in frypo for 20 minutes, washed, and dried. As a check, a leaf sample from a c o m plant which was not treated with radioactive material was mounted on X-ray film for a month; this film showed no autoradiographs after being developed.
The autoradiographs of the stem saaples were prepared ty cutting the fresh stem into two halves longitudinally. The stem was froten in a deep freezer and then dried ty lyophilization, so that it remained in its original form. For taking the autoradiograph, the dried stem sample was put on a piece of cotton in a box. Ify using the cotton cushion, a smooth contact vas obtained between the stem saaple anH the
film. The rest of the procedure was the same as described above.
Procedure of Analysis
Each of the harvested corn plants was dissected into tassel, upper
’eaves, lower leaves, upper nodes, lower nodes, internodes, midribs,
sheaths, and roots. If the ear was formed, it was separated into cob, husks, silks, and grains. Leaf margins were also separated from the
Hades. If there was an equal number of leaves or nodes, half were
classed as upper and half as lower; if there was an odd number of leaves
>r nodes, the center one was placed with the lower ones. The roots were washed with rain water. Corresponding parts of replicate plants were pooled, and the samples were dried in the oven at 70* C* for 48-72 hours.
When oven-dry, they were ground in a Wiley Mill through a 30-mesh screen,
ami stored In bottles for analysis.
Procedure of Analysing Samples Treated with Radioactive Materials
A portion of the vround saxple was weighed with a precision
tialance and spread uniformly in a small aluminum dish 3.6 cm in diameter.
This was mounted on the shelf of a G«iger-Muller counter and the radioactivity recorded. If the radioactivity of the sample was too
vvrtL, a larger aliquot was ashed in a muffle furnace at 800* F. for 3
hours, an.’ then tested. The amount of tissue used, time of counting
t r op cl determination, pre treatment, '-to., are given in Table 7.
The manipulation of the Geiger-Muller counter is described ly iuuaen (30) and Willard et al. (65). The plateau was determined with
fit (IH-E) 1103, a constant radioactive source obtained from the National
28 Table 7. Analysis of radioactive samples by G-M counter (1951-1953),
Working 5ackground Site of Treatment Time of voltage range sample Number of before counting of the (counts/ Year Element (mgm.) replicates counting (min.) Kind of G-H counter used plateau min,)
1951 Zn^5 300 2 ashed 10 Potter Instrumental Co. 1140 24-30 Model No, 2092 Tube No, 7553
1952 Znf5 20 4 none 5 Berkeley Scientific Co. 1050 28-35 Tube No. IF75
1952 5r89 10 4 none 5 Berkeley Scientific Co. 1050 28-35 Tube No. IF75
1952 Co60 200 2 ashed 5 Berkeley Scientific Co. 1050 28-35 Tube No. IF75
1952 j.'e55 300 2 ashed 5 Berkeley Scientific Co. 1050 28-35 Tube No. IF75
1953 Zn65 200 2 ashed 5 Potter Instrumental Co. 1200 17-23 Model No. 2092 Tube No. 7553
1953 Co60 200 2 ashed 5 Potter Instrumental Co. 1200 17-23 Model No. 2092 Tube No. 7553 Bureau of Standards* The radium standard was also counted hourly during the operation of the counter in order to make corrections for the fluctuations of the counter sensitivity caused ty the operational characteristics of the circuit and other environmental factors.
The radioactivity in the nutrient solution was determined ty dropping 0.1 ml of the concentrated solution on a piece of Whatman No. 2 filter paper and counting with the Geiger-Muller counter. The gravel was washed with 1 N HC1 and the radioactivity of this HC1 was determined*
The precipitates were included in the ash.
The standard of each radioactive isotope used in the experiments was prepared ty dropping a known amount of the stock solution on the filter paper. This was counted in the sane manner as was done with the c o m samples* The radioactivity of the standard was used to calculate the amount of the radioactive element in the samples. No effort was made to correct for errors such as coincidence loss, self absorption, wall absorption, etc*
The amounts of the radioactive element in the saaples used for autoradiographs were obtained from a concentration curve. This curve was constructed from the densities of a series of autoradiographs of the standard, taken at different time exposures, and the concentrations of the element corresponding to the various time exposures. Figure 6 shows the concentration curve of Zn^® used in 1951. The density was measured ty a Densichron densitometer.
S p e c trographic Analysis Procedure
Saaples of c o m which was not treated with radioactive isotopes
30 A U-4 o 1) o, ON V n*
-X — —• co .-
- t - 3 o
T M rv- qJ \ £ :/i o
i -£ is» ocy *- cr o o o ^ o ** •* ' \ <4 Vw \ c ** 0 -t 1 o
=-T
4. T ? * 4 r« ’ $ i A .1 o ^ yA'-'^cr^-
31 were analysed spectrcgraphically, using the procedure described by
Sayre (53). The ground samples were ashed ty heating in a muffle
furnace at 800* F. for 2-3 hours. A mixture of 90 parts lithiun fluoride and 10 parts ash was made for arcing. The lithium fluoride was used as a buffer, as well as the internal standard. The spectrograph used was made by Bauseh and Lomb Optical Compaiy, and had a medium quartz prism. Excitation was accomplished by 2200 volts AC arc at about 2.2 amperes. bach sample was exposed fire times, the exposures
’.wing 10, 15, 20, 25, and 30 seconds, in that order. Thus, the total exposure time for each sample was 100 seconds. The flat end carbon electrodes were purified according to the method described ty 7-ielton et al. (70). New electrodes were used only for new samples. Ten seconds prepare ajid 10 seconds pre-burning with the new sample were practiced for the new electrodes.
Eastman Kodak Compaiy No. 2 spectrographic analysis plates with emulsion No. 486,714 were used. The plates were developed with D19 developer at 68* F. for 6 minutes, fixed in typo for 20 minutes, and washed for 30 minutes.
The plates were read on a JA203 recording microphotometer manufactured by Jarrell-Ash Compary• The spectral lines measured were
H 2497, P 2535, Li 2741, Mg 2779, Mn 2801, Pb 2833, Si 2881, Fe 3020,
Al 3093, Ca 3159, Cu 3274, Ag 3280, and Zn. 3283. Twenty percent transmission was used for lithium, silicon, and copper. Molybdenum and cohalt were observed in the samples from plants grown at the higher concentrations of these elements, but they were not measurable.
32 A synthetic ash was made according to the method described ty
Sayre (53). Different amounts of the synthetic ash were arced with
90 mga. of lithium fluoride. The working curve (or concentration curve) was constructed from the concentration of the element in the synthetic ash-1ithium fluoride mixture and the ratio between the lines of the internal standard and that element. Figure 7 is the working curve of copper. o j: i>
\
0 o r 01 CA w v 1 ■ . ® 4. C*> r O 0 _ r~ o' V A ^ £ u XI <•> V>1 (i t-J,2 H,>e | 34 EXPERIMENTAL RESULTS AND DISCUSSION Experiment in 1951 In the gravel cultures, use of a nutrient solution of low pH (5.5), with a NOg/fcJH^ ratio of 70/30, not only did not injure the corn, but seemed to increase the rate of growth during the first half of the growing period. Twenty-four autoradiographs were made, two of which are reproduced in Figures 8 and 9. The analytical data of the experiment are given in Table 8. From an evaluation of the dista and the autoradiographs, the following conclusions may be reached: (1) The dry weight of every plant part except the ear was greater at pH 6.5 than at pH 5.5, although the total dry weights were almost the sane (at pH 6.5, 257.15 gm., and at pH 5.5, 258.32 g».). There was more sine in every part of the c o m plant at pH 5.5 than at pH 6.5 This indicates that greater absorption of zinc increases the yield of grain. (2) At pH 6.5, the tops of the corn contained about 1.5# of the zinc used in the nutrient solution, conpared to about 10# in the tops at pH 5*5. In other words, seven times as much zinc was found in c o m tops at the lower pH than at the higher. (3) At pH 6.5, about 78# of the zinc in the nutrient solution was retained ty the gravel, and only 8# remained in solution; at pH 5.5, the gravel held 23#, and 36# of the zinc was in solution. There was more zinc in the precipitate (including algae) at pH 6.5 than at pH 5. (4) leaf samples taken seven days after Zn®'* was added to the nutrient solution at pH 6.5 did not show an autoradiograph, even after Fig* 8*. Zn® accoulation in tho nodes of a corn plant (1951). Fig* 9* Zn65 accumulation in the embryos of corn grains (1951). IT- S' « # • t t (a ' S i ' Remarks: (1) PH 5.5 was lowered to pH 4 two weeks before the corn was harvested. (2) At each pH, 5 grains were taken from the same ear. The autoradiograph of the grain was printed by cutting the grain into two halves. The black spots are embryos where Zn^S is accumulated. (3) Dotted lines indicate the seed coat. (4) Time exposure, 20 days. 37 Table 8, The distribution of* Zn65 in corn plants (1951)• 10“5 >ugr of Total 10“ ~ Aip*' of Zn6® Dry Height (g») Zn65 in Each Plant per gn Dry Tissue Part of Plant pH 6.5 pH 5.5 pH 6.5 pB 5.5 pH 6.5 pH 5.5 Leaf 24.80 17.91 49.4 270.0 203.C 3 510.0 15# 85* Sheath 23.71 15.91 17.8 99.0 75. C 622.0 1.4* 4.2* Node 6.78 5.02 12.8 18.9 203.0 3770.0 32.8* Internode 22.72 13.72 3.6 16.2 16.1 11G.C ' Li Tri b 5.22 3.41 3.4 26.7 64.r 782.0 Tassel 5.99 3.91 2.6 3.5 42.8 91.0 Grain 77.33 108.68 33 cl 245.0 42.8 225.0 Cob 25.21 27.01 18.4 188.0 75.0 696.0 Silk 1.59 2.04 0.7 1.1 42.8 53.4 Husk 16.51 17.71 10.6 93 .O 64.2 525.0 5.2* Root 47.81 43.01 3 240.0 1480.0 2580.0 3440.0 Precipitation 3.63 3.93 318. 5 192.0 8250.0 4880.0 Solution 97C .0 4360.0 Grav«3 9500.0 2830.0 * Amount o f Zn6® calculated fron the radio auto graphs. twenty days exposure; corr e sp ond ding samples from plants cultured at pH 5.5 showed a very clear autoradio graph with an exposure of only eight days. (5) The autoradiographs showed that leaves near the tassel contained mich store sine than those near the bottosi of the plant. 38 Zinc n s distributed aore uniformly in the upper leaves than in the lever, older ones, in vhich it tended to accumulate along the veins. In the stems, line accumulated at the nodes, those of the shanks containing the highest concentration (Fig. 8). Zinc was distributed near the surface of the cob, and along the veins of husks and sheaths. (Although the sheath is a part of the leaf, it was considered separately.) The outer layer of the husks contained more sine than the inner layer. The concentration of sine was especially high at the junction between sheath and node. In the grains, sine accumulated in the embryos (Fig. 9)• (6) The parts of the corn plant in order of increasing sine accumulation are as follows: at pH 6.5: intemode < silk - tassel “ grain < husk * midrib < cob ■ sheath <. leaf • node < roots at pH 5.5: silk <. tassel intemode grain c. husk < sheath 4. cob < midrib < leaf <. roots < node At pH 6.5, when sine was poorly absorbed, accumulation was the same in leaves and nodes; but at pH 5.5, when the concentration of available zinc was much higher, accumulation in the nodes was even greater than in roots, although the roots also had the zinc adsorbed on their surface. This indicates that the nodes could serve as a storehouse for zinc in the c o m plant. Experiment in 1952 The analytical data of the gravel and solution cultures are given in Tables I-IY (Appendix), an! illustrated in Figures 10, 11, 14, 15, 39 19, and 22* A total of 51 autoradiographs were made, 9 of which are reproduced and shown in Figures 12, 13, 16, 17, 18, 20, 21, 23, and 24. The following conclusions regarding each of the elements studied may be reached. Sr69 (1) In the solution cultures, according to the data in Table I (Appendix), the accumulation of Sr**9 was greatest at pH 4 and least at pH 5.5. Accumulation in the gravel cultures was similar, but several parts of the plant contained more Sr89 at pH 7 than at pH 4. In both types of culture, the roots accumulated more Sr89 at pH 7 than at the other two pH levels. This night be due to higher adsorption or precipitation of Sr89 at pH 7. No adequate explanation can be given for the low accumulation of Sr89 at pH 5.5. (2) The nodes accumulated the greatest amount of Sr89 (Fig. 12), followed ty sheaths, roots, leaves, tassel, ear, and intemodes, in that order. In gravel cultures, the upper leaves contained about twice as such Sr89 as the lower leaves, while in solution cultures the difference between upper and lower leaves was not great. In both gravel and solution cultures, the upper nodes contained about twice as much Sr89 as the lower ones. The distribution of Sr89 in the c o m plant is illustrated in Figures 10 and 11. (3) The autoradiographs showed that Sr89 was distributed uniformly in leaf blades, but accumulated along the veins of the sheaths and the inner husks. In the grain, most of the Sr89 was concentrated in the basal portion, including the embryo and the point of attachment to the 40 JO s r %i $<*- a r f- 15 *S- 5SA *\ -i'-S* 4- 7 Xr,"t X r iatem *ah.tMK t G Jra^n. Jra^n. * / *> *. & I . W W ( * / ? - V * ' * xj . xa.e. tx-j- 4 \ \ ‘ SL a . ; / I x / _ ! . _ _ _ // /V ,_.J. 41 4 1 \\- Th*_ X>Sr^„ Corn fUnt I 40“< ^rowJrt (i> So\«t»on C.a\tu lt(.S . 40 -* ioo- ' A 43T- , ! I I 10- f w>- ' J r -Sfc. V '/ 30 A \ -X- f o c x j i M '. ; 4_ U. C. a. £- Q r 5 u. r\c Ki.'i't K i> \ a.cill - 42 OQ Fig. 12. Th* accuanlation of Sr in the nodes of the c o m plant (solution cultures, 1952). Fig.12. The accumulation of Sr L9 in the nodes Remarks* (1) The upper three are the third nodes from the top; the lower three are the second nodes from the bottom. (2^ Time exposure, 5 hours. (3) Dotted lines indicate the position of the stem. 43 Fig. 12. Tht accumulation of Sr**9 in th« node* of the corn plant (solution culture*r 1952). fig. 13. The accumulation of Sr®® in corn grains at pH 4, 5.5, and 7 (gravel cultures, 1952). ’ 9 * • * • * ^ • • * A • • Remarks: (1) The autoradiographs of the grains were printed by cutting each grain into 2 halves longitudinally. The upper side of each autoradiograph is the portion attached to the cob. (2) At each pH, the autoradiographs represent halves of 6 different grains taken from the same ear. (3) Exposure, 24 hrs. (4) Dotted lines indicate seed coat. 44 cob (Fig. 13). Zn**5 (1) In the gravel cultures, more Znto5 was absorbed at pH 4 and 5.5 than at pH 7f and half of the dissected parts shoved sore Znb® at pH 4 than at pH 5.5* However, in the solution cultures, the analytical data and the autoradiographs all showed that 7nb^ was accumulated more at pH 4 and 7 than at pH 5.5; there was a little more accumulation at pH 4 than at pH 7. Less accumulation at pH 5.5 in the solution cultures was probably caused ty the I8C50 resin, of which 50 gm. more was added to the pH 5.5 nutrient solution for a test in maintaining pH. Three conclusions may be drawn from these differences between pH levels: (1) Zinc accumulates more at a lower pH, but below pH 5.5 there is little difference (Fig. 14). (2) When the supply of sine is reduced ty a competitor of the roots (e. g., resin in the nutrient soltion), the sine content in the plant is decreased. (3) The plant can absorb more sine, even at pH 7, if more available sine is supplied. (2) In both cultures, nodes contained the most Zn®^, and intemodes the least. The other parts, in order of decreasing accumulation, are: roots, leaves, ears, sheaths, tassels, and midribs. The distribution of Znto® in the c o m plant is shown in Table II (Appendix) and illustrated in Figures 14 and 15. (3) In the gravel cultures, the upper nodes and leaves contained more Znto5 than the lover ones. However, in the solution cultures, the lever leaves contained more than the upper ones, though the upper nodes still had more Zn**® (Fig. 17). This may be due to the frequent supply 45 f. qi *>- V * _ 9 . I 4" O-Jf 2 j H i A C. O r r\ \ O. n' t — Qra^<\ i(\ ^}r *? H T -P H -f> H 4 to— cJ 5 5&- t) cn t I (<* * : 1 ^ 3CH o /! 2CH ! £ > A X ■\\ K' v N v / ■■ 'H V -- * I -// - > / . £ / J / / Ktfrt.4u^,iv, Gr-j arv. ,+. rrv. ■*- t Ra V JE*1? AV 46 ^ j n-ff f V. on Zn in Corn lf>\an't. C)yc>v*ifx i r. j£o\ju-fc.;*>r\ CL.ul1"ures • P H 7 ^ 'pH -S'-5" * P H 4 > i 40 - 3 0 - ?j- \ \ i i Ftp. lb. The accumulation of ZnD^ in corn leaves gemarks • (1) Lach autoradiograph was made from the basal section o: one-half of a corn leaf. (L) The numbers indicate the leaf number counted from the top. (3) Dotted lines indicate the edpe of the leaf section. (4) Exposure, 7 days. 46 Fig* lb. The accuMlitioo of Zn65 in corn le m s (gravel cultures, 1952), •K'O f t 48 Fig. 17. The distribution of Zntt5 in corn loaves of the whole plant at harvesting tine (gravel cultures and solution cultures, Aug., 1952). Reaiarkss (1) The position of the discs in the autoradiograph represents the actual position of the leaf on the plant. Two discs were need for the corn fron gravel cultures, one frost the nargin and one fTon the inside of the leaf. Only one disc was used for the corn fTon solution cultures. (2) Exposure, 13 days. 49 tpf (gravel cultures) (solution cultures) a . top top J top top 4*“ % ‘4a V * ,/ , r, . V ■ -Jt ’ 'A r, v '■ 'A' V i r H O t •• #• * \ I V* ft i It U <}' 99 it t I 9t n I // V * ■fHHlf) 50 Fig* 18. The increase of Z n ^ in corn leavss with tine (saaplss taken fTon plants grown in gravel col tores at an interval of 5 days; A u g • t 1952)• oo Fig.18 . The increase of* Zn in corn leaves with time Ren arks * (1) At each sampling date, three discs were taken, one from the margin, one from the middle part and the other from near the nidrib. The discs on the left side were from the margin. (2) The numbers indicate the leaf rn.ur.be r counted from the top. (b) Dotted lines indicate tr.e ed^e of the disc. (4) Exposure, S da^s. 51 Fig. 18. The increase of Zn^ in corn leaves with tiae (saaples taken froa plants grown in gravel cultures at an interval of 5 days; Aug., 1952). s! m ■ % !■ i i Q i • •• ' ;■ a ►' ■» ) Wm • •• *fW'% to1 Mia 49k jMl MM 10 9 . * % % ^10 i,S J8k J n - #••• Q p r '' >.r,l ,*■ i ■ ■ 'if + \ a i » ... i 51 of nutrient solution, resulting in the storage of Zn in the lower leaves. (4) The autoradiographs were similar to those made in 1951. Znb5 accumulated more in the upper portion of the plants; along the veins of older leaves, husks, and sheaths; and in the embryos of the grains. (5) Due to the shorter period of growth of the corn in the solution cultures with Zn6^, it contained less ZabS than that grown in the gravel cultures with Zn°5. This suggests that sine accumulation gradually increases with increasing time (Figs. 17 and 18). Co*0 (1) In both gravel and solution cultures, the lower the pH, the more Co®° accumulated in almost every part of the plant. In the gravel cultures, accumulation at pH 5.5 was not greatly different from that at pH 7, but at pH 4 it was about 5-10 times as great as at pH 7. The radioactivity of the used nutrient solution and the gravel washing shoved that the amount of Co60 retained on the gravel or remaining in the nutrient solution was practically the same at pH 7 and pH 5.5, but that four times as much Co*° remained in the nutrient solution at pH 4. This indicates that the gravel fixed a large amount of Co®0 , and this fixation was probably the cause of the reduced Co*0 content of the plant at pH 5.5. In the solution cultures, although the corn grew with Co*0 ten days less than that in the gravel cultures, the accumulation of Co fif) was about 5-10 times greater at all three pH levels. This might be 52 due to an increase in supply of available Co**® because of frequent irrigation. The younger age of the plants in the solution cultures night also be a factor in the greater absorption of Co**0 in these cultures• (2) The highest accumulation of Co00 was in roots (which night contain both adsorbed and absorbed Co60), followed Ijr leaf Margins, nodes, sheaths, ears, tassels, intemodes, and the non-marginal portions of the leaves, in that order. More cobalt accuMulated in the margins of the upper leaves than of the lower ones. In the case of nodes and non-marginal portions of the leaf, however, there was more cobalt accumulation in the lower parts. These differences were not great except in the case of leaf margins of the corn grown in solution cultures, in which there was about twice as much in the upper leaves as in the lower ones. The distribution of Co60 in the corn plant is shown in Figure 19 and also in Table III of the Appendix. (3) Autoradiographs showed that Co60 accumulated in the margins of leaves, the tips of husks, and the basal portions of grains (Fig. 23). The nodes contained about twice as much Co**0 as the intemodes. The cut edge of the leaf accumulated more Co60 (Fig. 20). The middle part of the leaf had much more Co**0 in the margin than the basal part, although the latter was cut eight days later and exposed 32 hours longer (Figs. 20 and 21)• This may be due to the movement of Co60 from the leaf to other organs. Fe55 (1) In both gravel and solution cultures, more Fe®° accumulated S3 000^1 V ’3- iq. IK«.'P;»V.>4^«n9f CG tb ;*v CorK^c*! 4*X>- 0-1. f>H 7 ( s S a-rxA 4- — - 9r 50- tr ,s) 40— -Oo Oo 50 * *? o 20 ■n A 1 0 .. S - «- T - 4 - 5 4 T? e marKs ■ Q r » . v « AQ . a * \-V -vjl r i . gr«»iK y\i,Ht C.0( 0 0 2 7 i®-')*) S o l u tioo C!u 14 ur C_ ( ^ o r f v Q t *W m W A C o b o At or , y a / y / y y y y / / — ^ ^ ------*£• ^ _ > y r v ^/ . 5 ' v y/ ,^/ ~Ra ?t*Auc.A; ■ftt. Or^aivs Lfc o.^1 13 i Qkjd.«s_ 54 60 Fig. 20. Co tcewulalion in the Biddle section of corn leaves at pH 7, 5.5, and 4 (gravel cultures, 1952). Remarks: (1) For each autoradiograph of the leaf sections, the left side is the leaf margin, the right side the side attached to the nidrib, and the upper side towards the tip of the leaf. (2) For the 3 pH levels, the top leaves were saapled fro* No. 3 leaf, the bottom leaves fro* No. 11 leaf. (3) Sampled Aug. 12, 1953; exposure was 4 days and 3 hrs. 55 Fig. 21. Co 6f) accumulation in basal section of corn leaves at pH 7, 5.5, and 4 (gravel cultures, 1952). f \ Remarks: (1) For each autoradiograph of the leaf sections, the right side is the leaf margin, the left side the side attached to the midrib, and the upper side towards the tip of the leaf. (2) Samples were from the same leaves as the leaf sections shown in Fig. 20. (3) Sampled on Aug. 20. L9&2; exposure was 5 days and 11 hrs. 56 at pH 4.5 than at pH b*7 in almost every plant part. The roots contained the highest amount of Fe'*'*, but this was both adsorbed and absorbed; the former might include the larger portion of the total Fe55. In the aerial part of the corn plant, the greatest accumulation of Fe®® occurred in the nodes, followed by leaves, sheaths, ears, and intemodes, in that order. In the ear, the cob and husks had a much higher content of Fe®® than the grains and silks. The upper nodes and leaves accumulated more Fe®® than the lower ones. The distribution of Fe®® is shown in Figure 22 and Table IV (Appendix). (2) The autoradiographs of the samples from gravel cultures showed that Fe was distributed uniformly in the leaves. The difference between upper and lover leaves was not great. The lower sheaths contained more Fe®® than the tipper, and the outer husks had more than the inner ones. In the grain, Fe55 accumulated in the embryo (Fig. 23). However, the autoradiographs from the solution cultures shoved that the upper leaves contained such mere Fe than the lover ones. It accumulated along the veins and to some extent along the margins and at the tips of the leaves and husks. The difference between gravel and solution cultures was probably due to differences in amount of Fe®® available. Evidently, when iron is abundant, it tends to accumulate more in the leaf margins and tips. Figure 24 shows the distribution of Fe^5 in corn grown in solution cultures, and also shows the increase in Fe®® concentration with increasing time. 57 £oooo - - 'X< tfoooo F\9‘ 22. 'TK l l).s+t^>4t;or\ ^ V-4. -S5 >rv C o *t . yJ W r ' t fc-7 oj.A.*t-5 ^ 3 0 6 0 0 9ro.va.\ SdUIiah Q.^w-uTe. Zcooo • V rf t-1 X p * 4--S I I / ±6000 * /; c^OOO \ 'i 7 0 0 0 -j Uoo-j 3 sw »-l * i ';•■ I, *°*j > ' ^ 2060 t $ \ooo- i 9«>" \ 7® “j fcoo- x i i i 400* J / / Y*r 2cfrn -j- - J * - j ? ^ ^ f J o / °y r f t j f f - d .o'o'/ ^ v " . ^■tcrrt. L«. C-c t v> fiemarks: (1) Each autoradiograph was printed fro* half of a grain cut longitudinally. A y each pH level, 6 grains were taken fro* the same ear. (2) Fe®® accumulates in embryos. Co®® does not show aiy particular localization of accumulation, but shows more in grains from plants cultured at pH 4 than at other pH levels. (3) Exposure, 27 days. 59 Fig. 24. FeSS accumulation in corn leaves at pH 6.7 and 4.5 (solution cultures, 1952). CS.) » tTT Remarks: (1) The left side of each leaf section is the leaf margin, the right is the side attached to the midrib. (2) For both pH levels, T is No. 4 leaf and B is No. 12 leaf. (3) Middle sections sajqpled on Aug. 17, 1952; basal sections sampled on Aug. 22, 1952. (4) Dotted lines indicate the edge of the leaf section. (5) Exposure, 28 dagrs. 60 Experiment in 1953 The dry weight; of the corn plants groira in soil and in gravel cultures are given in Tables 9 and 12, respectively. The data froa the spectrographic analyses are given in Tables Y-IX (Appendix), and the data relating to Zn**® and Co60 applied in the soil are given in Table 11. The amounts of all elements are expressed in micro grams per gram of dry plant tissue. The word "leaf* used in these tables refers to the portion of a blade without star gin and midrib. Tin and silver were also determined, though they are not included in the tables* Tin was found only in grains and tassels. Silver was found in every part of the plant, but was most concentrated in the margins of the upper leaves and in the upper nodes. The tassels, shanks, and ears also contained a considerable amount of silver. Results from C o m Grown in Soils It is evident from Table 9 that the dry weight of the c o m grown at pH 7.5 was much less than that of corn grown at pH 6.5 and 5*5, especially in Wooster silt loam. The retardation of growth at this pH was probably due to phosphorus deficiency during the younger stages, caused 1y heavy liming, or to some other unfavorable plysical conditions in the pot. But those c o m plants which overcame this deficiency made remarkable progress during the later stages of growth. This rapid growth during the later stages is clearly demonstrated ty the c o m plants used for the Zn6^ and Co*** experiment. On August 28, when the corn for spectrographic analysis was harvested (two months after planting), the corn plants in these six pots (two at each pH 61 Table 9. Dry mig h t of c o m g r o w in pots (average of 3 plants, in grans. Original pH: 7.5 0..5 5 .5 Varieties: Soils KL4 K24 K14 K24 K14 K24 Kooster S. L. 13.3 5.0 43.5 42.7 54.7 48.1 Mahoning S. C. L. 41.7 36.0 48*1 46.6 51.7 49.5 Fincastle S. L. 39.4 18.7 48.7 42.9 43 .b 43.1 Hooster S. L. (Zn^ added)* 53.1 70.4 82.7 looster S. L. (Co6® added)* 54.0 73.9 b2.3 * Only one plant, harvested 17 days later than the others. level) were about the sane site as those groan in Fincastle soil at the sane pH levels* In other words, if these six pots of corn had been harvested on August 28, the dry weight night have been about 19 gn*, 43 gn., and 43 gn*, at pH 7*5, 6*5, and 5*5, respectively (see Table 9)* After an additional seventeen days of growth, the dry weight of the corn at pH 7*5 had tripled, while that of the corn at the other two pH levels had about doubled. As denonstrated by the saaqples taken fron the field and fkoa pot cultures (Tables V and YI, Appendix), the accumulation of uost ainor elements was greater at lower pH levels than at higher pH, but the differences in total accumulation of minor elements at the various pH levels were not great (see Figs. 25 and 26), In the top of the corn plant, minerals seen to accusailate first in leaves and then in stems and other organa. Among the leaves, dead leaves contained the t>2 t t C'liner&L gm • 'I 5S- * ft* ^5* n X ^ v* 4 30 - zs- 7fr X lO- j ? * / y : >• ^ ' \ -*> r -^x '____ C S'V'C-«T\_ -*- Sht-O-t^, highest amount of Minerals, followed toy the ear gins of the lower leaves. An increase in aineral accumulation in the margins of lower loaves seemed to be an indication that the supply of mineral elements available to the plant was unbalanced, and the lower leaves were soon going to die. Sheaths are composed largely of conducting tissue serving as a bridge between nodes and leaves, and the amounts of mineral accumulation in the sheaths was intermediate between the nodes and the leaves. Under field conditions, high nodal accumulation of any mineral element was not found, except in the case of copper which had a slight tendency to show more in the upper nodes. In pot cultures, high nodal accumulation of sine and copper was clearly shown, especially in the corn grown in Mahoning and Fincastle soils (see Tables VTI and ¥111, Appendix). High sine accumulation in corn nodes was also shown by the experiment in which the soil was treated with (see Table 11). In the field c o m a considerable amount of minerals accumulated in the tassel, while in the pot cultures of the same type of soil, the tassel contained the least amount of minerals (Figs. 25 and 26). This difference was probably due to the fact that when the c o m samples were collected from the field the tassel was fully developed, but when the c o m was harvested from the pots the tassel was only half opened. This indicates that during the development of the tassel, a considerable amount of minerals was translocated into the tassel and accumulated there. Table 11 also shows that the tassel 65 contained about twice at anch Zn65 u the leaves; but, in corn plants of the sane variety in the sane soil which were harvested 17 days earlier, the tassel contained less sine than the leaves (see Table VI, Appendix). In order to get a rough idea of the accuaulation of ainor elenents under different conditions, the corn plants grown in the field and in pots were compared. As indicated in Table 10, the corn grown in the field absorbed more silicon, manganese, and iron. The accuaulation of silicon in field corn was about seven tiaes as great as that in the corn in pots. Although the difference in stage of growth should be taken into account, still the greater absorption of silicon by the field corn must be partially due to sane other reasons, such as the variety and the physical conditions of the soil. Table 10. The average concentration of ainor elements in corn plants grown in Wooster silt loan at different conditions (ag/gn. of dry plant tissue, average of three pH levels). Condition Variety 6 Mn Fb Si Fe A1 Ca Cu Zn Field W64 11 5340 169 3 10024 286 409 5363 16 78 Pot K14 6 4991 62 10 1320 114 317 4807 15 79 Pot K24 4 4731 65 8 1413 112 328 4906 17 83 Regarding the distribution of the individual elenents, almost every element followed one curve, as shown in Figure 25. All elements accumulated more in leaf margins than in other parts of the plant. Iron and lead also had a tendency to accumulate in the reproductive 66 organs. According to the amount accumulated in the plantf the ten elementa investigated can be classified into three groups: (1) silicon, calcium, and magnesium represented about 95JC of the total mineral elements accumulated; (2) aluminum, Iron, manganese, and sine represented about 4Jt; and (3) copper, boron, and lead represented only about ljt of the total ten elements accumulated in the field corn. The distribution of individual elements in the corn in pots followed the curve shown in Figure 26. All the elements except boron accumulated most in the margins of the lower leaves, and in dead leaves; boron accumulated more in the margins of the upper leaves. The results of the experiment with In®® in soil agreed with those of previous years, i. e., the higher the pH, the lower the accuaulation in every part. The highest accumulation of Zn65 was in the nodes. The analytical data are given in Table 11 and one of the autoradiographs is reproduced in Figure 27. With regard to Co®®, the data obtained in 1953 did not agree with those of 1952. In gravel and solution cultures, Co was found to accumulate more at the lower pH. But the data in Table 11 show that in soil cultures the accumulation was lower at pH 6,5 than at either pH 5.5 or pH 7.5. The autoradiographs of the corn leaf showed the same thing (Fig. 28). Co®® must have been changed in the soil of pH 6.5 in such a way that the absorption of cobalt by the plant was reduced. The data in Table 11 show the characteristic marginal and terminal accumulation. The large amount of Co®® in dead leaves was probably concentrated along the margins. 67 Fig. 27. The accuaulation of Zn®® in leaves of the corn grown in Wooster silt loan at 3 pH levels (1953). fieaarks: (1) The left side of each section is the margin of the leaf, the right side the side attached to the midrib. (2) For all 3 pil levels, T is No. 2 leaf and B is No. 6 leaf from top. (3) Time of exposure, 14 days. 68 Fig. 28. The largioal accuaulation of Co60 in leaves of c o m grown in Wooster silt loaa at 3 pH levels (1953). The marginal aecuu elation of Co leaves of corn Tow n in ,/oosrer silt loam. arks * '1) he upi^r three sect :.ors were taken from the second leaves an the lcv/er three sections wer- froin the fifth leave s . {£) hot ed lines iru icnte the cut ed t-a and the ed, e attached to midrib. (3 ; Exposure, 14 daj s. 69 Fig. 28. The aargiaal accumulation of Co®® in leaves of corn g in Wooster silt loam at 3 pH levels (1953). 69 jmargin 7 Mvcr.- Table 11. The distributions of Z n ^ sad Co®® in corn plants grown in Wooster silt loan (10*^Aigm./gm. dry plant tissue). Zn«* Co60 Part pH: 7.5 6.5 5.S 7.5 6.5 5.5 Tassel 86.2 268.0 273.0 3.52 2.10 4.08 Leaf 45.5 151.0 190.0 1.18 0.86 1.50 Margin 44.5 161.0 176.0 23.80 12.80 26.00 Dead leaf 42.7 55.7 65.3 22.10 2.49 58.50 Modes and shank 1L6.5 284.0 733.0 1.58 1.16 3.21 Internode 11.2 21.2 25.6 1.56 0.67 1.64 Sheath 18.2 63.6 146.0 1.55 0.96 2.25 Ear 58.3 167.0 174.0 1.10 0.57 1.66 Midrib 13.5 39.2 46.7 0.45 0.47 0.10 Dry weight of whole plant (gm.) 54.0 73.9 62.3 53.1 70.4 82.7 Results of the Corn Grown at High and Low Concentrations of Minor Elements The dry weight of the c o m after eachi treatment is given in Table 12, and the analytical data of the upper leaf blades and nodes are given in Table IX in the Appendix. Dry Weight Excluding the boron treatments, the c o m consistently had a higher dry weight at the higher concentration, and a lower dry weight at lower concentration, of the minor elements. The data also show that when the concentration of Iron, boron, or cobalt was low, the 70 Ttbl* 12. Dry weight of corn grown with low and high concentrations of minor elements (average of 4 plants, in grams). Low concentrations High concentrations Element Ave. pH Top Roots Total Ave. pH Top Roots Total Fe 7.3 37.6 6.3 43.9 7.1 48.8 10.6 59.4 Fe 6.4 43.4 7.2 50.6 6.2 51.8 11.7 63.5 Fe 5.3 45.6 7.8 53.4 5.1 51.1 12.1 63.2 Mn 7.3 45.1 6.1 51.2 7.0 47.0 10.1 57.1 Hn 6.3 43.0 5.6 48.6 6.0 54.3 11.0 65.3 Mn 5.0 39.6 5.6 45.2 4.1 47.9 9.3 57.2 Zn 7.3 43.5 5.5 49.0 7.1 52.9 9.5 62.4 Zn 6.4 46.5 6.4 52.9 6.2 54.4 10.3 64.7 Zn 4.8 40.3 6.4 46.7 5.1 66.0 8.9 74.9 B 7.3 39.6 5.3 44.9 7.0 38.0 6.3 44.3 B 6.3 43.2 6.5 49.7 5.8 38.2 5.9 44.1 B 5.2 44.2 6.5 50.7 4.6 42.7 6.5 49.2 Cu 7.2 46.5 5.3 51.8 7.1 65.4 10.9 76.3 Cu 6.0 42.3 6.4 48.7 6.1 68.7 12.8 81.5 Cu 5.1 52.0 8.6 60.6 4.8 53.5 8.9 62.4 Co 7.3 41.6 6.8 48.4 7.1 61.0 13.1 74.1 Co 6.3 31.0 5.4 36.4 6.1 59.3 11.5 70.8 Co 5.0 46.0 8.0 54.0 5.0 55.5 10.4 65.9 Mo 7.3 42.6 6.4 49.0 7.0 50.9 10.5 61.4 Mo 6.1 51.9 10.2 62.1 5.8 50.1 11.5 61.6 Mo 4.7 48.9 8.4 57.3 4.8 53.1 9.8 62.9 Check 7.1 45.0 7.4 52.4 Check 6.1 51.3 9.0 60.3 Check 5.0 50.6 10.3 60.9 yield was increased by lowering the pH below 6. On the other hand, when manganese, copper, or cobalt was in excess, lowering the pH to below 6 injured the roots and reduced the yield. At *he higher concentrations, zinc gave the highest yield at pH 5, while the cobalt gave the highest 71 yield at pil 7. It is noticeable that the lowest dry weight obtained was that of plants grown at pH 6.3 with a low concentration of cooalt, in spite of the fact that the corn should have grown better at this pH. If this low dry weight was due entirely to deficiency of cobalt, then cobalt should be considered as an essential minor element for the growth of coin. Boron Of all the minor elements used, only boron produced symptoms of toxicity at the higher concentration (Fig. 29). The first symptom Fig. 29. Marginal burning of co m leaves caused by ooron toxicity (Sept. 8 , 1953). 72 was nocturnal exudation ox' some sort of salt complex with a white colors along the margins of the upper leaves. Thi3 was observed at all three pH levels about one week after 12.5 p.p.m. of boron was added to the nutrient solution. Then the leaves began to turn yellow along the margins. Three weeks after boron was added, the marginal burning was more severe, especially on the upper leaves. The width of the burned margin was about l/4 to 3/4 cm. Chlorosis also occurred between the veins o! t;;e leaf, and the leaf was wrinkled. The younger leaves at the top of the plant were pale yellow. The analytical data show that the dry weights of both tops and roots were very low. In the terminal part of the leaf margin boron accumulated to about ten times the concentration in the non-marginal portion of the leaf blade, while the basal part of the leaf margin showed only twice as much boron as the non-marginal portion (see Table IX, Appendix). This corresponded to the wider marginal burning towards the tip of the leaf. Boron toxicity also induced an increase in marginal accumulation of other elements, such as magnesium, manganese, silicon, iron, aluminum, and zinc. It also increased silicon, calcium, and copper accumulation in the nodes, Manganese and Iron Manganese always accumulated more at the lower pH. High manganese concentration in the culture solution increased the accumulation of manganese in the leaves about five to ten times, and that in the nodes fifty times, as compared to the culture with normal rvanganese concentration. High manganese concentration also induced the 73 accumulation of more boron, magnesium, and silicon, but less iron, in the leaf margins. When the concentration of manganese was low, more iron accumulated in the leaf margins, and more calcium in the nodes. A high concentration of cobalt increased the manganese content in the leaf margins. Iron accumulated in the leaf margins when supplied at either high or low concentration. When the iron concentration was high, the ratio between copper content in the leaf margins and that in the non-marginal portion of the leaf was about 2 :1 ; when the iron concentration was low, this ratio increased to 4:1. This means that increasing the concentration of iron can suppress the marginal accumulation of copper in corn leaves. At pH 6 and 5, manganese accumulation was reduced in the upper leaves when the iron concentra tion was low. This iron-manganese relationship was not in agreement with the results of the manganese treatments mentioned above. Zinc and Copper High accumulation of tine in the nodes occurred in all treatments. At pH 7, a low concentration of' line resulted in accumulation of more manganese, iron, silicon, and aluminum in the nodes and more copper in the leaf' margins. Copper accumulated more in leal margins than in the non-marginal portion oi the leaves or in the nodes. This marginal accumulation was increased when the concentration of iron, molybdenum, or xinc was low in the nutrient solution. Calcium and Magnesium Calcium accumulated more in the nodes than the leaves. The pi 1 74 had little influence on calcium accumulation. High concentration of molybdenum or cobalt increased the accumulation of calcium ooth in nodes and in leaves. High magnesium accumulation was found in the nodes. When the concentration of molybdenum was high, the content of magnesium was increased, both in the leaves and in the nodes. In most cases, magnesium accumulated more at the higher pH. bi1i con, Aluminum, and Lead High accumulation ol silicon was always found in the leaf margins. At the high concentration of molybdenum, silicon accumulation was also increased in the nodes. Aluminum accumulated in leaf margins except when the concentration of manganese or molybdenum was high. Lead occurred in the leaves and nodes so irregularly that no conclusion could be drawn. 75 GhNFRAL DlbCUbblON The Influence of pH, boil, and Variety on Accumulation The results of this study show that, for most minor elements, there is more accumulation in com plants at lower than at higher pH. The influence of pH on the accumulation of minor elements is probably indirect. In the gravel and solution cultures, the amount of minor elements precipitated from the nutrient solution would be les3 at lower pH. In soil, a higher hydrogen-ion concentration not only results in the solution of more metallic elements, but may also cause the release of more mineral elements from the clay particles. Under normal conditions, a higher concentration of the mineral elements in the medium usually will increase the accumulation of the elements in the plants. Therefore, the major role of pH in the accumulation of mineral elements is that of making more mineral elements available for plant growth. It was observed that within the pH range of 5.5-7.5, the corn plants grew faster at a lower pH before the tasselling stage. The corn at the lower pH also began to tassel earlier. In the case of soil cultures, the corn grown at pH 5.5 had more dead leaves after tasselling. A similar growth response of lettuce and red clover at various pH values was observed by Warington (63). From these observations, it would seem that lowering the pH increases the rate of growth. Hut it is agreed in the field of plant physiology that pH per se does not have much effect on growth. The increase in growth rate must be due to some other conditions which are influenced 76 by the hydrogen-ion concentration, Phosphoru.- availability, which is easily influenced by the pH ol the nedium, is very influential in the growth ol' plants. It may be that the differences in growth rate observed in this work were not due to an increase at the lower pH, but rather to a decrease in growth rate at the higher pH because of a deficiency in available phosphorus. Ir. the case of the soil cultures at pH 7.5, this hypothesis is supported by the fact that nhosphorus deficiency symptoms were observed during part of the period of growth. However, it is unlikely that phosphorus deficiency occurred in the gravel and solution cultures, since the nutrient solution was replaced quite often. Therefore, phosphorus deficiency can not be considered as the only factor causing different growth rates at different pH levels. In the experiment using high and low concentrations of minor elements, the dry weight of those plants treated with a high concentration of a minor element was always higher than those treated with a low concentration, except in the case of boron. This indicates that increasing the concentration of minor elements under the toxic limit can promote the growth of the plant, if the supply of major elements is also adequate. At a lower pH, more minor elements are in the available form and therefore more minor- elements can be absorbed and accumulated in the plant. This may be another of the factors that caused faster growth of the corn at the lower pH. As the plant becomes older, the rate of metabolic activity is decreased and the absorbed minerals 77 tend to accumulate more in the leaves. This accumulation gradually increases to such an extent that it disturbs the internal physiolo gical condition of the plant and causes the dying of the leaves. In the case of the soil cultures, the increased growth rate of the plants at pH 5.5 caused them to age more rapidly than those at a higher pH. Consequently there was more accumulation of minerals in the leaves of the plants at pH 5.5, and therefore more dead leaves, at the tasseling stage. It is difficult to draw a conclusion from the experiment in 1953 as to the influence of soil on mineral accumulation in the plant. Although the coin grown in Mahoning and Fincastle soils accumulated more minerals than that grown in Wooster soil (Tables VI, VII, and VIII, Appendix), these differences in accumulation might be due to a drop in the pH of the Mahoning and 1 incastle soils during the period of growth (so- Table 2) instead of being !ue to differences in the soils. Hut, it is reasonable to think that the type of soil might influence mineral accumulation. A plant grown in soil which has a higher exchange capacity, better structure, or a higher concentration of minerals would be expected to have a higher mineral content. Therefore, the greater accumulation of minerals in the corn grown in Mahoning soil was very possibly at least partially due to other factors in the soil besides pH. bayre (54) reported that the magnesium requirement of corn was different in different varieties. This suggests that the accumulation of minor elements may also be different in different varieties. 78 However, in this study, there was no clearcut difference between K14 and K24, though K14 seemed to contain more minerals in the leaf margins and dead leaves than K24. The Location and Some Other Characteristics of Accumulation There are several factors which influence the location of high accumulation of the minerals in corn plants, namely, the characteristics of the mineral element, the supply of the element, the age of the plant, and other factors which affect the growth of the plant. Generally, when the supply of an element is abundant, there is greater accumulation in roots, nodes, or margins of upper leaves. When the plant becomes older or is grown under unfavorable conditions, the minerals accumulate more in lower leaves and the margins of lower leaves. Whether the element accumulates in leaf margins or tips, in nodes, or uniformly in leaves will depend upon the specific characteristics of the element. The mineral elements investigated in this work can be classified into three groups: (1 ) The elements which always accumulate in leaf margins, especially in upper leaves and near the tip of the leaf. Boron, silicon, and cobalt belong to this group. (2) Those which accumulate in leaf margins, but may, under certain conditions such as abundant supply, accumulate in nodes as well. Manganese, iron, copper, and probably aluminum are included in this group. (3) Those which accumulate in nodes, but may accumulate in leaf margins under unfavorable conditions. Zinc, calcium, strontium, and magnesium belong to this group. In old or etiolated leaves, all the minerals 79 accumulated in the margins, especially in the lower leaves. Zinc Zinc accumulates first in node3 . The radioactive work showed that the accumulation of zinc in nodes was even greater than in roots. This may be due to the fact that zinc is located in the chloroplasts, and is more important in the aerial portion of the plant than in the roots. It is possible that nodes may serve as a sort of storing and supplying center of z i n c f o r leaves. In field corn, zinc accumulation in nodes is less than in leaves (Table V, Appendix). This means that when the supply of zinc is insufficient, the zinc absorbed accumulates first in the leaves, and consequently no surplus zinc accumulates in the nodes. Zinc is usually more concentrated in upper leaves than in lower leaves. However, in the 1952 solution cultures, the lower leaves contained much more zinc than usual, although the lower nodes still had less than the upper nodes. This is probably due to the frequent irrigation which perhaps favored a higher rate of transpiration. All nodes may have attained saturation capacity lor zinc and the surplus zinc could only i>e stored in the lower leaves. Why the lower nodes still contained less zinc than the upper can not be explained. Cobalt This element accumulates in leaf margins, leaf tips, and roots, although the accumulation in the latter probably includes both adsorbed and absorbed cobalt. The amount of this element accumulated in plants is dependent more on its availability than on any other 80 factors. Figure 19 shows that, although the period of growth of corn in solution cultures with Co fin was ten days less than that in gravel cultures, yet the amount of Co®® in all parts of the plant was much higher in the solution cultures. Cobalt probably moves from the leaf margins to other organs when the corn becomes older. Figures 20 and 21 show that, although the basal sections of leaf samples were taken eight days later and exposed thirty-two hours longer than the middle sections of the same leaves, the amount of Coawfin in the leaf margins of the basal sections was much less than in the middle sections. Usually cobalt accumulates more towards the leaf tips, but in the samples of com mown st oH 4 the margins of the basal and i n die sections do not ' ->■ o v t, i , m j u s 'Figs. 20 and 21), althnu h t>.m are from the same 1 . 1 .►* vuttern of the marginal acc .■■■ ■ 1 a t i o,* I the two sections als * "i'fjrent. Perhaps a considerable amount >s the Co®® in the basal sections had moved out of the leaves ai t>?r t >e middle sections wei e .a-rul . CA In 1952, it was ‘ound th»f Co' always accumulated wore at a lower pH. However, in the soil cultures of 1953, the analytical data and the autoradiographs all showed that the content of Co®® was lowest at pFI 6.5 (Table 11). The dry weight of the corn grown with a low concentration ol co alt was also lower at pH 6.3 than at eitnrr :>H 7.3 or 5 (Table 12). These f acts indicate that pH may mfluer.ce the cobalt content in com. Young (69) reported that cobalt chloride precipitated rapidly when the pH reached approximately 6 . S. Therefore, in the case of the soil cultures, the added Co®®Cl2 alight 81 have precipitated around pH 6.5, thus decreasing the supply of available Co®®, and consequently the Co®® content of the plant. The low dry weight of corn grown with a low concentration of cobalt at pH 6.3, as compared to that at pH 5, might also be due to precipitation of cobalt, even though no cobalt chloride was added. The higher dry weight of corn grown at pH 5 with a low concentration of cobalt might be due to an increase in availability of cobalt from chemical impurities at the lower pH. However, the fact that the com grown in Wooster soil at pH 7.5 had more Co®® than that grown at pH 6.5 can not be explained. Possibly the retardation of growth it pH 7.5 might have delayed the maturation of the plant, and the younger corn might have been able to absorb comparatively more Co®® from the soil. btrontlum, Calcium, and iiagneslum Less 5r®® was absorbed at pH 5.5 than at pH 7 or 4. No reason f or this is yet known. Amon and Fratzke(2) reported that calcium was absorbed less at pH 4 or 5 than at a higher pH. Wadleich and Shive (62) reported that pH of the medium from 4 to 8 had little effect on base absorption and accumulation by c o m plants, but the absorption was influenced by the nitrogen form; calcium absorption was increased by nitrogen in the fonn of nitrate, arid decreased by nitrogen as ammonium. In this study the NOg/NH^ ratio was 95/5, 70/30, and 50/60 for pH 7, 5.5, and 4, respectively. It may be that at pH 7 the absorption of hr®® is not affected by the calcium and both may be abosrbed in the same amount (10). At pH 5.5 and 4, the 82 NO3 /NH4 ratio may affect the relative rates of absorptLon of calcium and strontium. In other words, at pH 5.5 with a NO^/NH^ ratio of 70/30, the c o m plant may absorb more calcium and less strontium, while at pH 4, the lower pH and lower NO3 /NH4 ratio may prevent the com from absorbing calcium but cause it to absorb more strontium. C o m plants grown in the field contained more magnesium and less calcium at higher pH, while the corn grown in Wooster soil in pot cultures contained more calcium and less magnesium at higher pH (Tables V and VI, Appendix). This difference may be due to the differences in Ca/Mg ratio. The ratios of exchangeable calcium and magnesium of the field plots at pH 6.7 and 5.3 were 6.2 and 6.9, while in the pot cultures of pH 7.5, 6.5, and 5.5 the ratios were 20.6, 3, and 2.8, respectively (see Table 3b). Higher Ca/Mg ratio retards the absorption of magnesium by the plant. Therefore, the field corn absorbed nore magnesium at higher pH, while the corn in pots absorbed more magnesium at lower pH. 83 SUMMARY 1. Three years work was carried out on the subject of minor element accumulation in co m plants in relation to the pH of the medium. Gravel, solution, and soil cultures were used for growing com. A new technique of intermittent irrigation was devised for solution cultures. 2. Radioactive isotopes of zinc, cobalt, strontium, and iron were used as tracers to study the accumulation of these four elements. Spectrographic analysis was also used for determining boron, manganese, magnesium, lead, silicon, iron, aluminum, calcium, copper, zinc, silver, tin, and phosphorus. 3. The pH of the nutrient solution in gravel and solution cultures was regulated by varying the NO^/NH^ ratio, and was also adjusted by sulfuric acid and potassium hydroxide when necessary. The pH of the soils was adjusted by adding lime to soils of pH 5.5. The soils used were Wooster silt loam, Mahoning silt clay loam, and Kincastle silt loam. 4. In general, in all cultures, the lower the pH, the more minerals accumulated in the plant. However, in the soil cultures using Wooster silt loam, some elements tended to accumulate less at pH 6.5 than at either pH 7.5 or -.5. The large quantity of minerals accumulated at pH 7.5 and 5.5 was largely in the lower and dead leaves. All comparisons were made on the basis of micrograms of element per gram of dry plant tissue. 5. Zinc accumulation was greatest in nodes, followed by roots 84 (adsorbed and absorbed). The tassel and the embryos of grains also accumulated a considerable amount of zinc. In the aerial, portion, the upper part of the plant contained more zinc than the lower part. Zinc accumulation, and also yield of grain, was increased by increasing the concentration of available zinc in the nutrient substrate. 6 . In the top ol the plant, cobalt accumulated in leaf margins or sometimes in the tips o' ot’or organs. The largest amount o', cobalt accumulated in roots (absorbed and adsorbed). Lower pH favored the uptake of cobalt by corn. In the soil cultures, the absorption of cobalt was lowered at pH 6.5, probably because of precipitation of cobalt chloride. When tL<-> jubalt concentration was very low in a nutrient solution of pH 6.3, the dry weight of com was reduced to such an extent that cobalt might be considered an essential element for the healthy growth of com. 7. Strontium, calcium, and magnesium accumulated more in nodes than in leaf margins. Ordinarily they were uniformly distributed in leaves. High calcium concentration in the soil suppressed the absorption of magnesium and vice versa. Strontium was absorbed less at pH 5.5 than at either pH 4 or 7. In the grain, strontium accumulated in the basal portion including the embryo and the point of attachment to the cob. 8 . In gravel and solution cultures, a large amount of iron was adsorbed on the roots. In soils, iron showed more in leaf margins but not in nodes. 9. Boron accumulated in the leaf margins, especially towards 85 t he tip of the leaf. Boron toxicity occurred when the boron concentration in the nutrient solution wasl2.5 p.p.m. This resulted in marginal burning of the leaves, chlorosis between the veins, and reduction in dry weight. The accumulation of other mineral elements in the leaf margins was also increased, but calcium and copper accumulation was reduced. 10. Manganese accumulated more in leaf margins. Within the pH range from 7.5 to 4, the lower the pH, the more manganese accumulated. Increasing the amount of manganese decreased the amount of iron in leaf margins. 11. Copper at a concentration of 0.6 p.p.m. did not impair the growth of com. It accumulated mostly in leaf margins, but sometimes was uniformly distributed and at other times accumulated in nodes. When the concentration of iron, zinc, or molybdenum was very low, the accumulation of copper in leaf margins was greatly increased. 12. bilicon and aluminum accumulated in leaf margins. Lead, tin, and silver all accumulated more in the tassels, grains, and silks. 13. When the c o m plant was young, more mineral elements accumulated in the upper portion. As it grew older, the accumulation of minerals shifted to the lower leaves. In etiolated or dead leaves, all minerals were accumulated in the leaf margins. The degree of marginal burning of the leaves was correlated with the amount of minerals accumulated. 86 LITERATURE CITED 1. Araon, D. I., and Stout, P. R. "Molybdenum as an essential element for higher plants.* Plant Physiol., 14 (1939), pp. 599-602. 2. , Fratske, W. E., and Johnson, C. M. HHydrogen-ion concentration in relation to absorption of inorganic nutiients by higher plants." Plant Physiol., 17 (1942), pp. 515-524. 3. Asen, S., and Davidson, 0. K. "Boron distribution in greenhouse rose plants." Proc. Amer. Soc. Hort. Sci., 56 (1950), pp. 433-438. 4. Danerjee, D. K., Bray, k. H., and Meisted, S. W. "Some aspects of the chemistry of cobalt in soils." Soil Sci., 75 (1953), pp. 421-431. 5. Barnette, R. M,, and Warner, J. D. "A response of chlorotic corn plants to the application of zinc sulfate to the soil." Soil Sci., 39 (1935), pp. 145-156. 6. Beeson, K. C., Gray, L., and Adams, M. B. "The absorption of mineral elements by forage plants: 1. The phosphorus, cobalt, manganese, and copper content of some common grasses." J. Amer. Soc. Agron., 39 (1947), pp. 356-362. 7. Biddulph, 0, "Interrelation between iron and phosphorus in plant nutrition." Oreg. Sta. Coll., Corvallis, Biol. Colloquium, Nutrition, (1948), pp. 24-27. 8. Brenchley, W. E., and Warington, K . "The role of boron in the growth of plants." Ann. Bot., Lond., 41 (1927), pp. 167- 187. 9. Brennan, E. G., and Shive, J. W. "Effect of calcium and boron nutrition of the tomato on the relation between these elements in the tissues." Soil Sci., 66 (1948), pp. 65-75. 10. Collander, E. "Selective absorption of cations by high plants." Plant Physiol., 16 (1941), pp. 691-720. 11. Eaton, F. M., and Blair, G. Y. "Accumulation of boron by reciprocally grafted plants." Plant Physiol., 10 (1935), pp. 411-424. 12. Elgabaly, M. M. "Mechanism of zinc fixation by colloidal clays and related minerals." Soil Sci., 69 (1950), pp. 167-173. 87 13. Epstein, E., and Stout, P. k. "The micronutrient cations iron, manganese, zinc, and copper: their uptake by plants from the absorbed state." Soil Sci., 72 (1952), pp. 47-65. 14. Fujiaoto, G., and Sherman, G. D. "Cobalt content ol' typical soils and plants of the Hawaiian Islands." Agron. J., 42 (1950), pp. 577-581. 15. G&uch, H. G., and Dugger, W. M., Jr. "The role of boron in the translocation of sucrose." Plant Physiol., 28 (1953), pp. 457-466. 16. Germar, B. "Some functions of silicic acid in cereal with special reference to resistance to mildew." Pflantenemahr. Dung. u. Bodenk. A 35 (1934), pp. 102-115. Chem. Abst. 29: 1461. 17. Headden, Wm. P. "Titanium, barium, strontium, and lithium in certain plants." Colorado Sta. Bull. 267 (1921). 18. Hibbard, P. L. "Accumulation of zinc on soil under long persistent vegetation." Soil Sci., 50 (1940), pp. 53-55. 19. Hill, A. C., Toth, S. J., and Bear, F. E. "Cobalt status of New Jersey soils and forage plants and factors affecting the cobalt content of plants." Soil Sci., 76 (1953), pp. 273-284. 2 0 . Hoagland, D. K, Lectures on the inorganic nutrition of plants. Waltham, Mass. Chronica Bot&nica Co., 1944. pp. 34-43. 2 1 . Hoffer, G. N. "Testing corn stalks chemically to aid in determining their plant food needs." Ind. Sta. Bull., 298 (1926). 22. , and Carr, R. H. "Iron accumulation and mobility In diseased corn stalks." I’hytopath., 10 (1920), p. 56. 23. ____, and . "Accumulation of aluminum and iron compounds in c o m in its probable relation to root- rots." J. Agr. Res., 23 (1923), pp. 801-823. 24. , and Trost, J. F, "The accumulation of iron and aluminum compounds in corn plants and its probable relation to root rots. J. Amer. Soc. Agron., 15 (1923) , pp. 323-331. 25. Ishizuka, Y. "Causal nature of toxic action of copper ions on the growth of rice plants. II. The abnormal accumulation of copper ions near the growth point of the root." J. Sci. Soil Manual, Japan, 16 (1942), pp. 43-45. 8 8 26. Jacobson, H. G. M., and Swanback, T. k. "Manganese content of certain Connecticut soils and its relation to the growth of tobacco." J. Am, Soc. Agron., 24 (1932), pp. 237-245. 27. Jacobson, L., and Overstreet, k. "The uptake by plants of plutonium and some products of nuclear fission adsorbed on soil colloids." Soil Sci., 65 (1948), pp. 129-134. 28. Jones, 11. E. , and Scarseth, G. D. "The calcium boron balance in plants as related to boron needs." Soil Sci., 57 (1944), pp. 15-24. 29. Jones, H. W. "The distribution of inorganic ions in plants and animal tissues." ;iiochem. J., 14 (1920), pp. 654-659. 30. Kamen, Martin D. "Radioactive tracers in biology." Ed. 2, New York: Academic Press, 1951. 31. Latshaw, W. L., and Miller, E. C. "Elemental composition of the corn plant." J. Agr. Res., 27 (1924), pp. 845-861. 32. Lohnis, M. P. "Manganese toxicity in field and market garden crops." Plant and Soil, III (1951), pp. 193-222. 33. Maze, P. "Influences respectives des elements de la solution atinerale sur le developpement du mais." Ann. Inst. Pasteur., 28 (1914), pp. 1-48. 34. ______. "Determination des elements mineraux rares necessaires au developpement du mais." C. K. Acad. Sci. Paris, 160 (1915), pp. 211-214. 35. . "Recherche d'un solution purement mineral© capable d*assurer 1*evolution complete du mais cultive a l*abri des microbes." Ann. Inst. Pasteur., 33 (1919), pp. 139- 173. 36. Mcilargue, J. S. "The role of manganese in plants." J. Amer. Chem. Soc., 44 (1922), pp. 1592-1598. 37. ______. "Effect of certain compounds of barium and strontium on the growth of plants." J. Agr. Res., 16 (1919), pp. 183-195. 38. McLean, t. T., and Gilbert, B. E. "The relative aluminum tolerance of crop plants." Soil Sci., 24 (1927), pp. 163- 174. 89 39. Millikan, C. R. "Effects on flax of a toxic concentration of boron* iron* molybdenum, aluminum* copper, zinc, manganese* cobalt* or nickel in the nutrient solution." Proc. Roy. Soc. Victoria, 61 (1949), pp. 25-42. 40. . "Radioautographs of manganese in plants." Aust. J. Sci. Res.* B4 (1951), pja. 28-41. 41. Otting, W. "Boron contents and distribution of boron in various plants." (Abstract) Z. Pflanzeneraahr. Dungung. u. Bodenk., 55 (1951), pp. 235-247. 42. Piper, C. S. "Investigation of copper deficiency in plants." J Agri. Sci., 32 (1942), pp. 143-179. 43. Rediske, J. H., and Biddulph, 0. "The absorption and translocation of iron." Plant Physiol.* 28 (1953), pp. 577-593. 44. . and Selders, A. A. "The absorption and translocation of strontium by plants." Plant Physiol., 28 (1953), pp. 594-605. 45. Reeve, E., and Shive, J. W. "Potassium boron and calcium boron relationships in plant nutrition." Soil Sci.* 57 (1944), pp. 1-14. 45. Riches, E. L., Brink, N. G., Kooiuszy, F. R.* Wood, T. R., and Eolkers, K. "Vitamin B-j^t a cobalt complex." Science, 108 (1948), p. 134. 47. kirie, D., and Toth* b. J. "Plant studies with radioactive calcium." Soil Sci., 73 (1952), pp. 1-10. 48. Robinson, W. 0., Steinkoenig, L. A., and Miller, C. F. The relation of some of the rare elements in soil and plants. D. S. Dept. Agr. Bull. 600 (1917). 49. 0, "Trace elements. I. Importance of strontium, barium, and zinc in the animal organism." Bull. Soc. Chim. Biol., 31 (1949), pp. 1052-1061. 50. Sanik, J.* Jr., Perkins, A. T., and Schrenk, W. G. "The effect of the calcium-magnesium ratio on the solubility and availability of plant nutrients." Soil Sci. Soc. Amer. Proc., 16 (1952), pp. 263-267. 51. Sayre, J. D. "Accumulation of radioisotopes in corn leaves. Ohio Agr. Expt. Sta. Res. Bull. 723 (1952). 90 52. . “Accumulated iron in the nodes of corn plants.** Plant Physiol., 5 (1930), pp. 393-399. 53. ______. "Spectrographic analysis of plant tissue.** Annual report to Office of Cereal Crops and Diseases, U. 5. D. A., 1944. 54. ______. “Magnesium, important element in c o m nutrition.** What's New in Crops and Soils, 5 (1952), pp. 16-17. 55. Shaw, E. **A dithizone tissue test for zinc in plants.** Soil Sci., 74 (1952), pp. 479-801. 56. , Menzel, H. G. , and Dean, L. A. “Plant uptake of zinc from soils and fertilizers in the greenhouse.” Soil Sci., 77 (1954), pp. 205-214. 57. Sommer, A. L, "Studies concerning the essential nature of aluminum and silicon for plant growth." Univ. Calif. Publ. Agri. Sci., 5 (1926), pp. 57-81. 58. ______. “Copper as an essential element for plant growth." Plant Physiol., 6 (1931), pp. 339-345. 59. Sprengel, Carl. Die Lehre vom Dunger. Ed. 2. Leipzig (1345), p. 512. Cited in U. S. D. A. Misc. Publ. 369 (1941), p. 23. 60. Trelease, S. F.t and Trelease, H. M. "Changes in hydrogen-ion concentration of culture solutions containing nitrate and ammonium nitrogen." Amer. J. Bot., 22 (1935), pp. 520-542. 61. Underwood, E. J., and Filmer, J. F. “Enzootic Marasmus. The determination of the biologically potent element (cobalt) in linonite." Aust. Vet. J., 11 (1935), pp. 84-91. 62. Wadleich, C. H., and Shive, J. W. "Base content of corn plants as influenced by pH of substrate and form of nitrogen supply." Soil Sci., 47 (1939), pp. 273-283. 63. Warington, K. "The effect of variation in calcium supply, pH value, and nitrogen content of nutrient solution on the response of lettuce and red clover to molybdenum." Ann. App. Biol., 37 (1950), pp. 607-623. 64. Webber, I. E. "Histological characteristics of plants grown in toxic concentration of boron." J. Agr. Res., 50 (1935), pp. 189-194. 65. Willard, 11. H., Merritt, L. L., Jr., and Dean, J. A. Instrumental methods of analysis. Ed. 2. New York: D. Van Nostrand Co., Inc., 1951, pp. 116-137. 91 66. Williams, C. H., and Moore, C. W. E. "The effect of stage of growth on the copper, sine, manganese, and molybdenum contents of Algerian oats grown on thirteen soils." Aust. J. Agr. kes., 3 (1952), pp. 343-361. 67. Wood, J. G . , and Womersley, H. B. S. "Development and metabolism of copper deficient oat plants." Aust J. Exp. Biol. Med. Sci., 24 (1946), pp. 79-94. 68. , and Sibly, 1'. M. "The distribution of zinc in oat plants." Aust. J. Sci. kes., 3 (1950), pp. 14-27. 69. Young, k. A. "Some factors affecting the solubility of cobalt." Soil Sci. Soc. Amer. Proc., 13 (1948), pp. 122-126. 70. Zielton, k., Hamm, P., and Nelson, k. C. "The purification of spectrographic carbons." Science, 94 (1941), p. 348. 92 APPENDIX Table I . The distribution of Sr8® in corn plants * Dry we ight (g«./plant)* 10“^-4igj*. Sr89/gm. dry tissue Part pH 7 pH 5.5 pH 4 pH 7 pH 5.5 pH 4 (Gravel Culture) Tassel 3.7 3.2 2.6 22.4 28.4 18.2 koots 43.0 47.0 42.0 60.4 26.6 38.6 Upper nodes 3.9 4.1 4.1 80.0 58.4 91.6 Lower nodes 10.8 10.8 6.9 30.7 27.6 48.8 Internodes 38.6 52.2 35.9 10.1 7.0 14.2 Upper leaf 12.2 13.0 12.0 34.9 40.4 24.9 Lower leaf 15.4 17.9 12.6 11.3 18.0 12.7 Shanks 4.0 7.6 7.6 17.9 10.0 18.2 Husk 22.3 32.0 23.” 5.0 2.6 4.4 Sheath 18.1 21.0 18.7 61.7 50. 3 53.5 Silk 2.0 2.4 1.6 6.4 6.5 4.9 Grain 34.1 21.2 16.1 1.3 1.5 2.3 Cob 30.2 30.3 26.0 4.5 3.8 3.6 Midribs 6.5 r'.8 6.1 26.5 25.? OO • o Q Total 244.8 269.5 215.9 (Solution Culture) T assel 6.7 5.3 4.8 21.7 16.2 32.1 koots 28.0 23.0 28.0 131.? 54.1 63.8 Upper nodes 5.0 4.1 5.2 105.0 82.2 118.2 Lower nodes 9.3 7.2 8.0 55.8 32.8 79.9 Internodes 58.8 47.8 47.8 11 .6 8.4 19.5 Upper leaf 17.4 16.2 17.0 17.1 13.6 21.6 Lower leaf 16.4 14.0 13.8 18.9 9.4 16.1 Shanks husks 7.5 4.7 5.9 7.6 5.2 10.6 Sheath 19. f 18.7 17.9 71.8 61.0 81.5 Silk ♦ cob 3.1 4.8 4.0 12.9 14.5 24. 4 Midribs 12.0 11.1 11 .8 14.7 24.9 19.2 Total 183.8 157.1 164.2 * For solution culture, dry weight is expressed as gm./2 plants. 93 >. Table II. The distribution of in6® in corn plants. * 14 ) -7 Dry weight (gm./plant)* 10‘ Aigm. Zn65/g». dry tissue Part pH 7 pH 5.5 pH 4 pH 7 pH 5.5 pH 4 (Gravel Culture) Tassel 3.8 4.0 3.7 624 950 785 Roots 39.0 60.0 48.0 2370 2652 3180 Upper nodes 2.9 5.4 4.6 2660 9160 7120 Lower nodes 8.5 7.2 7.7 1152 3950 2475 Intemodes 31.2 38.7 36.0 247 222 405 Upper leaf 13.5 12.5 15.3 464 1620 1545 Lower leaf 14.8 15.1 15.1 381 1540 1360 Shanks 5.0 5.9 5.5 820 1510 2540 Husks 25.0 20.9 26.0 516 800 503 Sheath 18.5 20.6 19.6 250 1005 1010 Silk 2.7 1.5 2.0 2.6 579 600 Grain 26.4 15.3 31.1 2.3 564 472 Cob 33.4 32.7 28.4 329 570 635 Midribs 7.0 6.0 7.0 655 650 635 Total 231.7 245.3 249.9 (Solut ion Culture) Tassel 5.4 5.3 4.8 462 570 595 koots 18.0 29.0 26 .0 5720 2960 1265 Upper nodes 3.2 3.8 3.0 5930 4700 6720 Lower nodes 6.2 7.5 5.8 2780 2440 4350 Intemodes 34.7 46.7 32.7 176 207 352 Upper leaf 14.0 17.4 14.8 628 310 488 Lower leaf 14.5 13.8 13.2 1190 622 1045 Shanks ♦ hv.sk s 6.6 4.4 7.3 335 824 607 Sheath 16.7 18.6 16.0 695 322 582 Silk + cob 5.6 2.3 7.2 930 366 726 Midribs 10.4 10.6 10.2 460 253 522 Total 135.3 159.9 141.5 * For solution cultures, gm./2 plants. 94 pp Table III. The distribution of Co^® in corn plants. CT ____ Dry we i£ht (gm./plant)* 10 "7 Aigm. Co60/g»- dry tissue Part pH 7 pH 5.5 pH 4 pH 7 pH 5.5 pH 4 (Gravel Culture) Tassel 2.7 4.1 4.2 5.9 3.5 46.3 Koots 42.0 39.0 48.0 638.0 1785.0 5220.0 Upper nodes 3.8 4.7 4.9 5.4 11.4 59.3 Lower nodes 7.3 7.7 9.9 6.1 8.8 70.4 Internodes 33.6 41.5 44.0 2.0 4.4 31.7 Upper leaf** 9.5 10.7 11.3 5.9 9.0 24,5 Lower leaf** 12.1 10.8 17.5 6.2 11.4 28.1 Shanks 5.4 4.2 7.6 4.5 5.4 40.1 Husks 18.5 22.7 39.1 5.6 5.6 21.6 Sheath 21.0 19.6 22.1 5.4 10.8 47.2 Silk 1.5 1.5 2.0 4.0 9.9 70.6 Grain 10.6 17.3 17.5 2.9 3.2 15.2 Cob 30.1 30.3 30.3 6.9 8.6 21.4 Upper 1. margin 2.0 2.2 2.6 27.0 30.0 262.0 Lower 1. margin 2.2 2.3 2.2 16.9 28.4 259.0 Midribs 6.6 6,6 8.2 3.1 4.9 12.9 Total 208.9 225.0 271.4 (Solution Culture) Tassel 6.4 6.6 4.8 66 112 151 Koots 21.0 22.0 23.0 7620 16600 23700 Upper nodes 4.0 4.4 4.8 98 198 802 Lower nodes 6.2 7,4 7.2 113 224 382 Internodes 44.1 53.8 53.9 67 111 149 Upper leaf 16.6 14.5 15.5 26 44 164 Lower leaf** 9.8 11.3 13.0 41 87 242 Shanks ♦ husks 11.9 8.1 6. 6 36 74 131 Sheath 17.7 19.2 19.9 59 114 190 Silk + cob 6.3 4.7 4.5 42 114 148 Upper 1. margin 2.7 3.5 2.9 405 752 1450 Lower 1. margin 2.3 2.6 2.5 150 347 810 Midribs 10.2 12.0 12.3 19 47 93 Total 159.2 170.1 170.9 a For solution culture, gm./2 plants. **■* Leaf without margin. 95 pp Table IV. The distribution of F e ^ in c o m plants. ~.vt ______ Dry weight (gm./plant)* 10" Fe55A ® . dry tissue Part pH 6.7 pH 4.5 pH 6.7 pH 4.5 (Gravel Culture) Tassel 4.2 2.4 275 1610 Moots 52.0 39.0 8050 54800 Upper nodes 4.0 2.4 2950 2320 Lower nodes 7.9 6.3 438 3170 Internodes 40.0 26.7 107 1100 Upper leaf 12.2 10.5 643 2580 Lower leaf 14.0 12.4 320 1970 Shanks 4.8 5.4 283 542 Husks 36.0 21.2 148 820 Sheath 22.5 14.2 1065 1815 Silk 3.3 2.4 214 423 Grain 15.5 36.0 275 595 Cob 30.2 27.4 1890 2150 Midribs 7.5 5.4 410 985 Total 254.1 211.7 (Solution Culture) Tassel 7.2 5.7 823 3380 Moots 27.0 29.0 65200 19600 Upper nodes 4.7 4.9 4430 37700 Lower nodes 6.3 8.2 4550 5170 Internodes 50.1 49.1 632 1010 Upper leaf 22.5 19.2 1180 6360 Lower leaf 14.2 14.7 1190 3650 Shanks ♦ husks 14.4 9.3 2010 4840 Sheath 21.3 21.8 730 1900 Silk ♦ cob 8.4 5.1 2680 2050 Midribs 13.5 12.7 664 1530 Total 189.6 179.7 * For solution culture, gm./2 plants. 96 fkpp Table V. The distribution of minor element* in corn plants grown in the field (/ugm./gm. dry tissue, ->,* average of 3 plants). Dry weight (gnu/plant) Ash (%) B Mg Mn Part pH: 6.7 5.8 6.7 5.8 6.7 5.8 6.7 5.8 6.7 5.8 Upper leaf 14.05 16.45 10.10 10.09 trace trace 12625 6610 283 324 Lover le a f 13.55 14.95 10.32 11.30 ... 12900 9620 175 272 Upper 1. margin 3.25 3.30 10.68 9.95 74.80 91.80 11214 4680 662 1095 Lover 1. margin 3,35 3.58 10.45 10.54 36.60 31.60 13585 5580 418 495 Upper node 7.15 6.20 4,72 4,09 mmm 4059 3110 5 7 Lover node 15.95 17.32 3.65 3,65 mmm ... 4380 3290 36 120 Internode 55.00 71.50 2.20 2.35 2860 2820 3 4 Midrib 8.75 9.10 7.50 7.76 m + ^ 12375 5587 66 113 Sheath 23.95 24.10 6.81 7.23 • w 11577 9761 225 405 Husk 34.30 34.40 2.07 1.88 2.28 3.57 2588 1974 26 32 S ilk 2.25 2,66 6.72 5.72 14.11 15.44 1512 1344 7 5 T assel 5.50 5.04 5.21 4.68 12.50 12,64 4897 2808 99 n o Cob 27.40 23.10 3.11 3,95 4.67 6.32 1524 1126 17 28 Grain 37,55 41.20 2.69 2.60 6.99 8.84 1453 1534 3 8 Shank 7.75 8.80 2.09 2,13 2.51 1.44 1338 1470 6 16 Total 259.8 281.7 154.46 171.65 98887 61314 2031 3034 App Table V (continued)* >. - T Jj______ Pb Si Fe A1 Ca Part pH: 6*7 5.0 6.7 5,8 X7 5X 6.7 5.8 6.7 5.8 Upper le a f 3,85 2.93 11110 20200 566 495 586 628 12120 12610 Lower le a f 3,41 4.29 6914 11850 557 882 877 1108 12180 14180 Uuper 1. margin 6,09 3,88 45924 53800 320 478 534 688 13350 15410 Lover 1. margin 3,66 5,35 31350 56800 669 812 1118 1370 13400 12150 Upper node 1.20 1,48 434 310 14 17 83 68 3587 3690 Lover node 1,31 0.80 584 280 17 15 102 58 3760 4490 Internode 0,62 0.33 726 510 24 8 84 52 1496 1833 Midrib 3,15 1,63 3075 4074 116 118 300 326 5925 5432 (c Sheath 4.70 1.23 4631 7953 184 311 361 615 3814 5495 ® Husk 1.39 0.98 1635 6768 81 12 124 207 861 808 S ilk 3.16 3.43 1344 1173 74 69 296 280 1256 1201 Tassel 9.64 3,65 9899 11144 782 782 625 725 3387 3557 Cob 1,65 3.00 2923 3674 467 593 292 514 1089 1383 Grain 5,25 0.81 199 403 22 35 44 56 471 390 Shank 1,19 0,96 523 511 18 21 67 72 784 777 Total 50,26 34.75 121271 179450 3911 4648 5293 6767 77480 83406 Table V (concluded). Part Cu Zn Total pH: 6.7 5.8 6.7 5.8 6.7 5.8 Upper leaf 41.41 20.20 114 156 37449 41046 Lower leaf 21.67 23.70 101 99 33729 38039 Upper 1. margin 13.88 20.90 121 144 72720 76412 Lower 1. Margin 12.54 14.20 125 119 60718 77377 Upper node 23.60 28.70 49 65 8256 7297 Lower node 17.99 17.20 38 37 8936 8308 I n t e m o d e 2.49 2.10 23 20 5219 5249 Midrib 11.25 10.70 81 78 21952 15740 Sheath 20.10 4.60 87 81 20904 24627 Husk 9.32 8.46 30 36 5358 9850 Silk 13.76 13.44 84 92 4604 4196 Tassel 23.97 6.55 94 115 19829 19264 Cob 14.31 17,78 62 95 6395 7440 Grain 8.74 8.06 43 51 2256 2495 Shank 20.90 16.40 43 53 2804 2938 Total 256.03 212.99 1095 1241 310629 340278 Table VI. The distribution of minor elements in c o m plants grown in Wooster silt loam ^ugm./gm. dry T'tissue, average of 3 plants). ’v. Variety Ash {%) B «S Mn and Part pH: 7.5 6,5 5.5 7.5 6.5 5.5 7.5 6.5 5.5 t.5 X i 5.5 K 14 Upper leaf 6,92 6.83 6.89 6.83 8.95 1142 3074 6070 18.68 21.17 82.60 Lover leaf 10.82 9.14 8.93 22.41 2056 6581 10550 11.36 13.25 69,80 Upper 1. margin 7.03 7.23 7.41 11.95 16.76 63.80 1547 3470 5330 43.59 39.77 167.00 Lover 1. margin 9.80 9.32 9.58 15.88 5.39 27.80 2646 7176 11020 186.20 125.82 341.00 Upper node 6.54 4.49 4.08 ... — 4.00 1570 2694 2930 7,85 1.08 2.69 Lover node 5.43 2.94 1.85 ... 1.85 1466 2587 2920 3.80 0.50 0.14 Internode 4.43 2.40 1.70 « m m 1.70 1085 1536 2720 5.54 0.24 3.58 Midrib 5.52 5.50 4.40 1297 5170 8580 16.28 7,70 52.30 Tassel 5.66 3.39 3.91 — 5.76 7.32 1302 1831 1760 4.78 2.68 8.40 Sheath 6.32 4.54 3.88 — 3.00 1643 5221 7390 19.59 19.07 105.10 Dead leaf 14.48 11.98 12.20 — 3.30 10426 15574 24300 210.00 65.89 374.00 Total 27.63 57.15 127.22 26174 54914 83620 527,67 297.17 12D7.11 K 24 Upper leaf 6.28 5.97 5.90 4.10 3234 2860 72.20 10.80 8*O 8Z dO 1411 45.36 Lower leaf 18.40 8.24 ---- 18.50 5544 10880 10.50 82.40 Upper 1. margin 6.60 6.88 16.30 35.80 2706 3910 27.10 117.00 lo.oo1 fi 'JC lu.yo1 A A O i9601Q9Q U r Lower 1. margin 8.40 8.94 • « * 17.00 4452 8410 70.60 246.00 Upper node 4.90 5.15 ^ v ** m m ** 2891 3770 1,80 7.00 Lover node 11.14 2.73 2.51 ------2061 2867 3210 2.56 0.70 2.20 I n t e m o d e 2,29 2.34 — ---- 1786 169C h.40 1.70 Midrib ... 4.05 4.30 — — - o> ---- ... 4374 8400 8.30 66.30 Tassel 4.03 3.82 6.80 • ■* — 1451 1620 --- 2.60 3.70 Sheath 9.13 3.93 4.17 ---- 2054 4244 5420 65.74 24.00 85.50 Dead leaf 11.32 10.99 11,55 10,03 ---- 5660 13188 18400 277.34 81.33 294.00 fief Table VI (continued). Trx 5 j t) Variety Pb Si Fe A1 and Part pH: *?.? 6.5 5.5 ?.5 6.5 5.5 t.5 6.5 5.5 7.5 6.5 5.5 K 14 Upper leaf 2.70 5.05 5.72 394 1025 1820 41.52 81,96 103,2 249 342 365 Lower leaf 5.63 10.05 7.78 660 1462 1970 58.43 89.57 134,0 395 411 492 Upper 1. margin 4.08 10.48 6.30 808 1207 2000 53.43 104,94 71,2 267 362 293 Lower 1. margin 20.58 21.44 72.00 2205 3076 4320 245.00 265.62 566.0 *27 699 172 Upper node 8.83 14.82 4.70 294 233 350 27.47 13.25 10.6 180 85 82 Lower node 5.86 4.56 7,42 141 159 231 14.66 5.59 5.4 119 53 49 I n t e m o d e 2.17 2.35 2.72 89 130 715 9,52 3.24 20.4 95 30 61 Midrib 9.66 3.79 4.63 420 1045 1540 14.90 57,75 114.3 135 242 238 Tassel 1.37 0.98 4.10 153 258 606 14.43 17.29 20.7 125 95 133 Sheath 4.36 9.08 3.46 373 1044 1480 18.33 29.06 79.t 152 168 214 Dead leaf 20- 27 16.77 12.80 4199 3354 5740 695.04 215.64 574.0 1564 815 1150 Total 86.01 99.27 131.63 9736 12993 20842 1192.73 883.81 1699.5 3908 3302 3249 K 24 Upper leaf 7.22 6.83 1382 836 103.6 49.6 320 269 3.09 759 58.21 278 Lower leaf 12.18 8.69 1344 2810 60.5 231.0 353 602 Upper 1. margin 17.16 6,00 957 1890 51.5 100.0 281 392 11,29 1797 129.58 451 Lower 1. margin 18.06 11.20 1890 4830 130.2 438.0 445 894 Upper node 4.70 3.82 211 320 9.3 12.6 87 111 Lower node 10.25 3,82 3.14 111 120 220 117.00 5.1 5,5 49 50 50 Internode 3.09 1.46 128 230 4.2 3.2 38 30 Midrib 4.05 5.80 — 782 2450 — 25.1 215.0 ... 146 390 Tassel 1.81 1.68 --- 129 203 — 9.5 11.1 ... 50 380 Sheath 4.29 3.54 4.71 730 707 1170 48.39 17.3 62.5 228 108 200 Dead leaf 24.34 17.03 10.35 2830 2967 6340 243.38 225.3 648.0 906 659 1080 4902 4371 4990 8390 11668 23353 12466 18499 12875 11687 5951 5127 8092 3556 9354 3212 9728 10542 21004 16277 36361 42471 5866 5646 6446 9984 5509 6642 3178 13638 38317 106871 129203 150662 85.2 6258 56.2 89.5 5387 60.5 51.2 44.3 59.2 76.2 97.5 50.0 86.0 42,3 182.3 102,8 110.8 919.1 161.0 78.08 38.80 44.5 49.50 46.2 83.3 61.02 38.1 78.6 85.92 82.2 87.56 83.8 82.9 77.3 77,9 27.5 47.67 100.8 125.80 140,5 105.32 — ,54 45.0 ,69 47.2 ,50 — —— 61.94 50.78 88.29 58.48 22.56 37.5 74.71 81,.14 72.6682.23 73.76 117.60 104, 118, 9.7 68.89 5.7 122, 8.1 4.6 9.8 31.7 12.0 13.0 12.8 67.86 10.4 22.1 15.7 14.9 12.8 17,0 10.5 21.4 147,,16 131.9 159.3 909.9S 775.99 6.05 8.6 6.9 7.56 9.4 6.5 7.80 8.4 7.5 40.41 12.98 16.27 12.03 10.6 15.18 22.3 14.9 10,2 11.1 15.4 13.9 20.6 15.88 42.9 178.43 5.76 3.42 6.70 6.64 7.68 9.16 3.57 m * w * 9.14 28.91 23.30 11.13 30.03 36.20 20.97 21.1 166.52 63.39 10.50 65.21 153.78 765 5.66 2290 4440 5180 2220 1450 2690 6620 3700 2340 3550 6790 2510 6290 932 927 790 1824 300 3960 4049 1958 3097 1630 2606 3449 3100 3178 2350 9506 2352 3234 7586 2812 1900 U O O 2835 6552 6132 2669 16173 10150 14067 10150 4297 6963 5601 3445 3460 3919 7546 3303 4616 1500 7858 4361 21000 18678 Variety Ca Cu Zn Total and and Part pH: 7.5 67§ 573"" 7.5 6,5 3."5 7,5» 6.3 5,& "773 675 53 Upper 1. margin Lover leaf 6708 Internode Upper node Lower node K K 14 Lover node I n t e m o d e Lower 1. margin Total 64155 55702 38775 Sheath Upper node Lover 1. margin Upper leaf Midrib Tassel Tassel Lower leaf Upper 1. margin SheathDead leaf 5935 Midrib Dead leaf K 24 Tfpper leaf Table VI (concluded). 102 fity App Table VII, The distribution of minor elements in some parts of corn plants grown in Mahoning silty t? ys(y- 'U.j 3 J clay loam ^igr../ga. dry tissue, average of 3 plants). Variety Ash {%) B ...Mg.. Mn and Part plir 7 6 5 7 6 5 7 6 5 7 6 5 K 14 Upper leaf 7.27 7.88 8.17 4.9 8.7 7.1 2472 3388 3513 40.0 55.2 506.5 Upper 1. margin 7.89 7.41 8.12 23.7 31.9 60.1 3156 3779 4791 98.6 81.5 1299.2 Upper node 6.36 5.64 5.91 4.3 3.1 — 2671 3102 2660 3.1 3.8 97.5 c n * Tassel O * u i 4.49 4.67 4.7 5.4 7.0 1502 1572 1868 4.1 3.7 79,4 Dead leaf 16.76 13.42 12.30 20.1 11.5 16.0 164.5 13688 10578 653.0 503.3 2521.5 K 24 Upper leaf 7.30 7.18 7.70 5.7 6.8 9.2 2555 3087 3465 52.6 79.0 739.2 Upper 1, margin 7.05 7.93 7.44 32.4 23.8 35.7 2679 3013 3794 105.8 150.7 930.0 Upper node 6.02 6.05 5.80 3.7 3.3 — 2769 2027 2233 3.7 2.0 84.1 Tassel 5.42 4.00 3.96 4.2 5.6 5.9 1680 1300 1505 2.4 3.2 41.6 Dead leaf 14.88 13.31 14.72 11.4 16.2 10382 10304 306.1 1472.0 App Table VI1 (concluded), TrW., (.T* Variety Fb Si fe A1 and Part pH: 7 6 5 7 6 5 7 6 5 7 6 5 K 14 Upper leaf 3.85 3.47 6.45 1636 2679 3758 116 122 131 385 496 490 Upper 1. margin 7.42 3.56 5.36 3551 2579 5197 181 111 166 450 371 495 Upper node 4.07 1.18 5.14 207 310 680 10.5 9.0 29.6 114 54 185 Tassel 1.34 24.25 25.22 211 359 1121 12.9 11.5 63.0 95 99 257 bead leaf 37.69 13.15 10.95 12060 9931 61500 988.3 684.4 725.7 1441 1194 1415 K 24 Upper leaf 2.26 6.46 11.55 2336 2527 5698 127.8 183.1 173.3 409 424 585 Upper 1. margin 3.53 13.08 4.98 1763 2855 5878 112.8 178.4 204,6 317 460 432 Upper node 16.25 3.03 16,53 343 236 186 14.1 9.1 5,8 144 82 29 Tassel 1.14 0.74 4.75 211 384 400 10.03 15.6 9.3 73 128 59 Dead leaf 7.99 13.25 10648 25760 825.2 515.2 --- 1371 1443 Ca Cu Zn K 14 Upper leaf 3926 4098 4085 13.1 8.5 9.2 6i.i 66,2 98.0 Upper 1, margin 4655 3297 4385 18.1 22.6 11.8 77.3 66 7 113.7 Upper node 3371 2707 2334 26.7 6.8 12.7 100.2 101.5 159.6 Tassel 1186 840 1214 9.0 5.8 11.0 67.5 58.4 67.7 Dead leaf' 32663 14762 10947 52.8 31.5 38.7 214.4 171.8 246.0 K 24 Upper leaf 4015 4236 3966 14.1 16.5 14.2 66,6 91.9 107.8 Upper 1. margin 4300 4758 3869 16.6 21.8 14.1 77.6 91.2 98.2 Upper node 3401 1664 2030 19.3 13.0 6.0 78.3 96.8 220.4 Tassel 1084 780 824 7.6 8.6 8.1 55.8 60.0 59.4 Dead leaf 12911 13984 26.6 33.9 m + m 166.4 257.6 SUE Tassel node Upper ed leaf Dead asl5.89 Tassfl K 14 K ed leaf Dead K 24 K pe 1 margin 1. Upper pe la 8.58 leaf Upper Upper node Upper grown plants m o c of parts some in elements ofminor distribution The VTII, Table Upper leaf Upper pe 1 margin 1. Upper n Pr p;7 5 6 7 pH; Part and Variety loam ^ugm./gm. dry tissue, average of 3 plants). 3 of average tissue, dry ^ugm./gm. loam 10.18 50 17.17 15.03 14.59 7.32 .67.05 8.63 7.96 .54,39 7.75 8.02 s (JO Ash 15.45 7.56 5.66 7.13 4.15 4,32 7.08 17.97 14.34 7.03 7.76 4,57 .46.4 4.64 7.98 7.20 3.94 5.12 13,5 15.0 16.1 . 7.8 6.7 0.7 1.0 7.8 5.2 . . . 7 3725.5 43.7 22.7 13.0 16,5 5522.5 15.5 . 5.0 4.5 . 7.2 4.8 . 4.4 3.5 4.0 6 B 32.6 15,8 5.3 . 1561 5.3 6.3 7 5 12839 543326 1574 2170 7665 2416 2246 3868 2188 2149 15914 13736 3226 1951 1404 3993 3115 8833 119.4 3830 3878 1273 gMn Mg 6 21 481.5 12619 80368.2 5840 4467.3 3414 39748.4 7.4 1379 1371 2458 1995 3672 3374 5 78.6 18141330.4 114.1 61.8 11*1 in 5.9 7 2.9 icsl silt Tincastle 123,9 755.5 192.8 190.4 579.4 9.9 6 3.6 2.6 1147.2 934.4 446.4 605.3 574.6 49.2 22.9 27,8' 16.5! 5 Table VIII (concluded). - ______ Variety Fb Si Fe A1 and Part pH: 7 6 §" 7 6 5 7 6 5 7 6 5 K 14 Upper leaf 2,75 2.99 8.79 2360 2139 2671 124.4 121.2 161.7 386 385 520 Upper 1* margin 4.38 4.94 7.34 2468 2327 2953 119.4 134.0 119.7 382 367 415 Upper node 94.93 9,13 7.19 285 374 436 15,1 18.7 15,8 74 122 104 Tassel 7,36 0,82 0,75 459 354 256 21.2 13.0 7.9 147 78 38 Dead leaf 30,64 7.42 28.68 14298 12360 37284 2188.5 695.3 2151 343 1298 1620 K 24 Upper leaf 7.70 6.37 23,76 4251 2195 3456 36.1 155.8 165.6 465 375 511 Upper 1. margin 8.27 6.28 17,07 2635 3175 4811 117.1 143.6 170.7 304 416 497 Upper node 15,58 10.19 6.14 199 640 333 U . 2 22.1 9.7 71 161 69 Tassel 2,56 1.32 2.15 527 140 356 21.7 6.6 12.3 167 42 103 Dead leaf 22.55 8.41 10.78 11273 46359 51215 826.7 566.6 611.0 1533 1322 1671 Ca Cu Zn K 14 Upper leaf 4204 3672 2742 12.9 U . l 17.9 73.8 85.6 92.8 Upper 1. margin 3662 3631 3272 12.7 12.5 13.6 68.5 88,1 107.7 Upper node 3107 1536 1346 22.0 22.0 22.3 120.8 141.1 185.6 Tassel 1531 886 670 9.1 5.8 6.1 75.4 60.5 51.2 Dead leaf 20426 14214 9895 84,6 15.9 68.8 201.3 231.8 322.7 K 24 Upper leaf 3769 3044 3456 18.0 19.5 18.0 93.8 92.0 108.0 Upper 1* margin 3001 3175 3570 13.5 17.8 23,7 61.5 90.7 126.5 Upper node 5599 2094 1715 7.4 28.3 12.5 325.6 226.4 297.0 Tassel 2232 790 914 8.5 6.6 9.4 102,3 52.6 70.8 Dead leaf 14279 11847 8266 60.1 180,3 24.8 187.9 271.3 296.5 Table IX. The accumulation of minor elements in upper leaves and nodes of c o m plants treated with \ T -t-tl) high and low concentrations of minor elements Ougn./gm. dry tissue, average of 4 plants). Treatment Ash {%) B Mg Mn and Part pH: 7 6 5 7 6 S' 1 6 5 7 6 5 Check Upper leaf 7.72 7.34 7.39 19.3 17.0 14.8 950 793 562 17,0 23.5 44.3 Upper margin 6.90 6.81 7.02 345.0 653.8 449.3 1194 1178 758 65.6 136.2 221.1 Upper node 10.98 10.14 9.71 12.1 8.0 10.7 3239 1572 2039 4.5 6.2 27.2 High Mn Upper leaf 8.20 7.75 8.01 10.7 15.5 12.0 1009 891 609 360.8 395.3 252.3 Upper margin 7.45 7.10 7.28 395,0 397.6 320,3 1512 1385 968 521.5 497.0 484.1 Upper node 10.17 11.18 11.10 81.0 30.2 12.2 1759 2627 2442 289.8 357.8 380.7 Low Mn Upper leaf 7.70 7.68 7.90 54.0 10.8 22.1 1117 707 774 12.0 26.0 90.9 Upper margin 6.80 7.00 6.68 408.0 259.0 347.1 1360 1050 721 46.2 77.0 136.9 Upper node 11.89 12.63 11.24 11.2 9.3 8.8 3032 2526 1630 4.8 19.6 32.6 High Fe Upper leaf 6.82 7.19 7.33 7.5 11.5 10,3 907 791 689 15.3 39.6 80.6 Upper margin 6.21 6.77 6.87 139.7 284.3 171.8 981 934 687 34.8 155.7 182.1 Upper node 10.81 10.88 11.55 9.1 11.0 9.7 2054 1741 1964 3.9 11.4 22,5 Low Fe Upper leaf 7.35 7.58 7.72 17.0 9.9 10.8 992 553 648 19.1 16.7 50.2 Upper margin 6.32 6.47 6.86 233.8 304.1 329.3 1062 731 563 38.6 84.1 99.5 Upper node 12.00 11.66 11.30 9.0 8.6 6.6 2580 1609 1220 2.8 8.9 29.0 Table IX (continued). Treatment Pb Si Fe A1 and Part pH: 7 6 5 “1 6 7 6 5 7 6 5 Check Upper leaf 43.25 84,41 98.29 517 514 429 43.2 43.3 37,7 259 255 259 Upper margin 39.33 98.75 72.31 1173 1703 1966 67.6 98.8 70,2 255 320 288 Upper node 20.86 9.53 6.80 82 56 78 11,5 8.1 12.1 48 21 51 High Mu Upper leaf 69.70 38.75 28.04 500 566 425 41.8 41.1 28.8 324 314 224 Upper margin 37.20 31.24 32.70 1325 1740 2111 55.1 56.9 48.0 285 270 242 Upper node 1.63 2.70 5.22 54 67 125 8.5 12.3 18.0 29 32 70 Low Hn Upper leaf 26,18 18.05 20.94 277 246 371 35.4 43.8 57,0 219 221 277 Upper margin 28.56 22.40 26.05 1632 1190 1403 95.2 73.5 73.5 303 280 284 Upper node 18.43 7.83 24.73 65 82 97 13.1 16.4 15,2 45 52 56 High Fe Upper leaf 48.42 46.02 36.65 293 352 388 31.1 43.1 53.0 211 226 244 Upper margin 55.90 49.42 48.10 1043 1388 1305 59.6 95.0 72.1 ' 248 257 264 Upper node 10.70 54.40 4.04 72 94 81 12.0 22.3 11.6 44 51 58 Low Fe Upper leaf 24.26 51.54 17.76 470 205 301 37.5 27.3 38.0 234 163 208 Upper margin 20.36 22.65 23.32 948 1165 1544 42.3 64.7 58.3 219 249 281 Upper node 20.76 16.32 14.70 78 76 57 11.3 14.0 11.1 67 42 33 hpn Table IX (continued'. W. v T ' i i O Treatment Ca Cu Zn and Part pH: 7 6 5 7 6 5 7 6 D Check Upper leaf 3937 4257 4212 19.3 33.8 40.0 92.6 135.8 221.7 Upper margin 3588 3746 3229 45.0 47.0 53.4 100.1 153.2 196.6 Upper node 6588 4512 7768 10.0 4.8 5.7 313.0 375.2 1165.2 High Mn Upper leaf 4510 5580 3685 36.1 29.5 20.0 106.6 128.0 116.1 Upper margin 4843 4402 4878 44.7 47.0 36.4 111.8 120.7 145.6 Upper node 5797 6820 7104 6.1 7.4 10,0 274.6 469.6 976.8 -i Low Mn High Fe Upper leaf 5251 5249 5204 24.0 31.6 31.5 99,0 133.0 234.6 Upper margin 4533 1333 4809 55.3 78.0 59.1 105.6 176.0 219.6 Upper node 6162 6963 8201 4.0 8.0 16.7 313.5 674.6 1132.0 Low Fe Upper leaf 4043 3638 3551 12.5 13.3 17.4 125.0 104.6 204,6 Upper margin 3539 3559 3087 46.8 62.1 57.6 103.0 116.5 151.0 Upper node 5520 7113 6667 5.3 8.5 8.0 294.0 618.0 1103,0 Apr Table IX (continued). ,. r '>4. m ) Treatment Ash {%) B i Hn and Part pH*. 7 6 £ T 6 5 r 1 ? 5 ~ T t 5 High B Upper leaf 9.41 8.99 8.96 847.0 1066.8 940.8 1129 978 878 30.1 55.1 103.0 Upper margin(t) 10.56 11.03 11.03 8448.Q 1E147.6 9265.2 2218 2018 1599 86.6 154,4 253.7 Upper margin(b) 8.80 8.11 8.25 2332.0 2230.3 2887.5 1320 1135 1196 54.6 93.3 194.0 Upper node 13.91 13.33 12.59 76.5 88.5 103.2 2782 2904 2644 10.3 17.3 74.3 Low B Upper leaf 8.23 7.48 7.60 8.1 4.1 8.4 906 667 562 20.6 21.0 48.6 Upper margin 6.87 6.66 7.09 55.2 14.0 20.6 1138 732 582 55.2 53.3 110.0 Upper node 12.78 11.40 11.53 8.7 6.9 5.5 2930 205o 1380 10.3 11.0 59.8 ^ '*igh Q Upper leaf 8.15 7,54 7.99 8.97 13.60 12.00 880 701 591 13.4 28.7 33.6 Upper margin 7.39 6.95 7.11 236.50 264.10 298,00 1109 855 711 45.8 76.5 113.3 Upper node 11.13 10.86 10.30 8.20 7.10 9.30 1892 1520 1782 5.2 14.7 33.0 Low in Upper leaf 8.01 8.27 8.37 9.60 10.80 13.40 801 769 619 14.9 26.5 49.4 Upper margin 7.02 7.08 7.39 224.60 311.50 236.50 793 850 591 40.7 74.3 103.5 Upper node 11.77 11.27 12.36 11.50 10.20 11.10 2531 1578 1854 18.2 11.0 37.1 Upper leaf 7.39 8.15 7.29 9.60 9.00 9.50 680 693 643 11.1 17.9 32.8 Upper margin 6.39 7.47 7.23 158.50 194.20 203.00 861 994 675 40,0 71.0 79.7 Upper node 10.43 10.14 10.43 8.00 10.10 7.30 1931 2028 1720 4.3 6.6 13.6 98 66 48 827 394 446 325 205 340 314 247 250 254 234 376 "T* 69 39 24 31 46 993 A1 260 313 347 236 142 280 277 53 68 1 40 361 334 813 311 376 148 265 102 248 317 255 266 240 232 233 5 86.0 67.3 53.6 69.5 16.7 36.5 15.0 10.2 46 44.0 39.4 65.4 331.0 206.3 1.4 17.0 6 1.1 54.8 63.1 299 81.8 fe 12,4 38.1 79,9 97.1 81.4 10.2 14.9 44.7 12.7 45.2 46,5 117.6 < •J 9.4 13.6 92.4 73.9 27.2 15.3 53.4 63.4 39,1 11.7 37,0 42,0 232.3 297.3 84 42.4 58 5 72 73 157 435 726 56.5 243 407 409 3419 1315 1403 1240 65.5 1182 1215 6 97 69 71 bi 292 957 104 314 729 407 432 172 3530 1321 15«9 1234 1310 7 72 71 141 950 207 184 913 495 302 362 1583 1206 2432 1109 0 7.81 97 5.19 3.61 7.72 56.93 27.50 38.39 48.55 11.40 20.20 80.50 37.69 43.15 30.70 49,64 £ Pb 4.01 5.21 3.35 29.20 25.30 28.50 36,60 24,40 36.11 19.72 82.20 21.10 44.12 36.19 30.97 8.71 3.34 3.75 16.02 28.30 44.50 23.87 23.43 26.60 24.70 32.60 33.26 ______- i t Upper margin Treatment Upper margin Upper margin(b) 28,16 and and Part pH: 7 Upper node Upper node 2.92 Upper node High Cu High Zn Low B Upper margin Upper node Upper margin(t) 34.85 Upper leaf 17.41 61.34 71.68 405 Upper leaf Upper leaf Low Zn Upper leaf Upper leaf Upper node Upper margin >■ - - >■ I l l Apt- Apt- Table IX (continued). b~ M V z u Upper node Upper Upper margin margin Upper Upper leaf leaf Upper Treatment (continued) IX Table Upper margin(b) margin(b) Upper o B Low Upper node Upper pe nd 5841 node Upper margin Upper pe leaf Upper Upper margin(t) margin(t) Upper 7 pH; Part and pe node Upper Upper leaf leaf Upper pe margin Upper node Upper Upper leaf leaf Upper Low Zn Zn Low Upper leaf leaf Upper B High Upper margin margin Upper ih Cu High 9181 4157 3432 3100 3380 4048 4134 8004 6122 6500 5317 3524 3399 3991 2948 Ca 5320 9958 4633 4466 2840 7402 3540 3510 3487 5379 6082 4147 2730 5334 5677 6875 5 6 7 3 6 12590 4743 4950 3420 3067 3880 6077 4235 5300 3190 5914 6035.1 3620 3591 4269 5740 8652 42,7 43.3 26.5 11.1 12.2 30.8 46.3 27.3 21.6 34.7 7.5 9.3 6.9 , . 6.9 8.4 6,6 5.2 Cu 37.5 47.] 34.8 10.1 43.0 43,9 42.6 11.3 10.6 29.3 59.8 21.5 9.9 6.2 5.8 33.1 44.9 40.5 29.6 34.3 25.6 11.9 39.8 52.8 57.6 11.3 16.2 8.5 8.5 7.2 5.6 431.2 118.2 496.0 158.4 0, 179.3 103,4 0. 138.6 103.5 506.1 133,0 121.4 121.4 456.3 271.2 91.0 90.5 91.3 82,5 97,0 y 456,0 476.6 142.0 142.0 206.3 103,4 128.6 450.8 108.3 738.5 857.5 169.0 150,8 82.2 Zn 83.4 6 1030.0 1297.8 1700.0 921.0 160.0 129.0 281.3 710.0 175.0 177.8 177.8 149.0 272.3 272.3 277.8 140,4 150.7 175.8 s 5 19.4 27.9 49.1 15.9 72.7 17.3 72.7 40.4 24.3 49.6 145.7 204.0 137,3 110.1 125.1 6 8.6 9.9 12.3 Mn 30.9 15.4 30.5 29.6 82.6 22.6 73.2 36.5 15.5 79.2 70.2 149.0 7.3 5.9 3.8 4.4 9.0 T 16.2 89.9 32.7 19.2 23.1 13.3 18.4 93.2 51.4 60.2 5 541 517 575 890 582 592 531 1340 2508 1512 1075 1347 1046 1195 2610 809 662 925 MS 760 914 975 1878 3308 2040 1071 1433 1118 1167 2490 2091 T 746 130 848 785 841 149 258 866 1820 1690 3555 1620 2709 1215 2360 6.r. 5 7.30 7.30 6.40 10.20 16.20 11.20 10.50 16.30 10.50 362.00 276.10 311.60 193.30 276.90 8.00 8.10 B 8.90 13.50 12.40 12.00 11.90 10.00 291.00 350.00 309.10 320.60 257.30 “ r m « 7.10 m 3.10 9.70 T 10.50 10.20 10.50 13.10 11.10 160.00 313.00 373.90 279.00 337.60 8.46 8.08 8.17 8.71 7.10 8.08 7.^7 7.70 7.42 7.58 10.30 10.95 11.17 11.40 10.85 {%) 6.59 7.54 6,97 7.93 8.31 3.24 8.07 9.25 7.43 7.16 11.36 10.67 11.04 12.67 11.38 - . 1 8.11 7.34 3.76 7.13 6.93 8.10 7.46 7.34 7.19 6.07 12.90 11.51 n.u 11.75 10.11 if i and Part pH: High Co High Mo Upper margin Upper node Low £u Upper leaf Upper leaf Upper margin Upper node Treatment Ash Upper margin Upper margin Upper node Upper leaf Upper margin Upper node Low Cg Upper leaf Upper node Low Ho Upper leaf . . Table iuued),cont IX ( f\ 113 Table IT (continued). yX. 2.1) Treatment lb______bi______jje______AT______and Part pH: 7 P 5 7 6 5 7 6 5 7 6 5 U>K Cu Upper lead' 47.00 21*80 35.53 615 317 296 56.8 42.8 43.2 267 230 228 Upper margin 24.30 22.50 67.50 1165 1141 1611 66.5 76.0 99,7 389 275 368 Upper node 3.68 6.28 20.66 76 68 78 14.6 10.0 17.9 33 40 35 High Mo Upper leaf of.70 62.62 52.29 527 453 637 43.7 53.6 71.1 267 297 335 Upper margin 30.20 45.24 31.16 1438 1282 1261 61.8 79.2 68.3 249 271 293 Upper node 4.56 13.87 7.52 108 110 111 12.2 15.5 18.2 97 83 109 Low Mo Upper leaf 41. u . (-r 363 2V 267 41,1 36.4 29.1 274 246 182 Upper margin 57.20 55.80 56.80 1430 1360 1136 75,0 75.2 55.4 311 314 259 Upper node 15.00 15.40 22.68 99 80 67 12.6 12.0 11,9 31 31 37 *11 gh Co Upper leaf 49.50 36.50 50.90 361 291 550 39.2 33.3 46.8 240 224 272 Upper margin 43.2n 4 1.70 47.90 1640 1525 1425 89.5 78.2 77.0 294 251 289 Upper node 6.78 2.32 3.04 76 89 93 9.1 13.8 13.6 39 62 85 Low Co Upper leaf 37.67 32.30 30.49 394 490 235 39.4 76.8 36.6 254 393 209 Upper margin 28.63 31.50 31.84 1395 1539 1137 54.3 78.8 54.6 272 301 235 Upper node 10.71 8.74 13.69 90 101 55 16.8 17.7 8.5 49 52 32 5 145.7 848.9 228.8 160.7 178.1 889.2 181.8 186.0 156.2 177.0 939.6 715.0 143.7 113.7 624.2 In 83.2 142.8 112.5 570.0 121.1 140.1 129.0 500.0 443.0 646.2 661.5 158.0 114.6 120.3 163.0 7 6 97.2 95.8 87.7 79.0 99.1 334.0 328.0 109.4 107.0 134.0 238.9 138.0 324.0 100.7 387.0 < ■ • • ■ 5 7.6 7.9 8.4 49.9 33.4 44.1 14.4 17.4 49.0 50.8 39.5 11.7 17.0 44.0 8.7 7.4 9.5 9.5 6.7 12.7 Cu 45.5 42.2 58.7 34.6 10.7 22.0 12.3 34.1 43.2 3.3 7.9 7 6 6.1 6.6 7.6 6.0 30.9 30.0 46.5 45.8 10.1 35.4 47.7 11.4 45.5 3 3680 3260 6536 4961 3232 6255 7296 2911 5400 5037 6300 5620 9550 3108 3789 6 6258 2940 5170 3540 Ca 6262 3720 6920 9710 4110 2828 5080 8300 6335 5140 3099 1 3040 5220 49 f. f. 49 3810 6075 3310 59«o 7721 3290 3986 3376 5820 6579 6330 7700 node High Mo Upper margin and Part pH: Upper leaf Upper node Upper leaf Upper margin Upper leaf Treatment High Co Upper node Upper node Low Cu Low Mo Upper margin Upper margin Low Co Upper node Upper margin Upper Upper leaf Upper leaf App Table IX (concluded). 115 AUTOBIOGKAPHY I, Yuan-pin Chou, was born in Muping, Shantung province, China, March 5, 1922. I received my high school education in the church schools in Peiping, China. My undergraduate training was obtained at the Tokyo Institute of Technology, Tokyo, Japan, from which T received the degree bachelor of science in 19 48. I did graduate work in the University of Tokyo during the years 1948-1950. While in residence at the University of Tokyo, I taught in the Chinese High School of Tokyo. In 1951, I received an appointment as University Scholar at the Ohio State University to do graduate work. I held the position of kesearch Assistant in the Department of Agronomy, Ohio Agricultural Experiment Station, for three years while completing the requirements for the degree Doctor of Philosophy. 11.6