Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1937 Translocation of carbohydrates in sugar beets Oliver Andrew Leonard Iowa State College Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Agricultural Science Commons, Agriculture Commons, Agronomy and Crop Sciences Commons, and the Plant Pathology Commons Recommended Citation Leonard, Oliver Andrew, "Translocation of carbohydrates in sugar beets " (1937). Retrospective Theses and Dissertations. 13629. https://lib.dr.iastate.edu/rtd/13629 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. NOTE TO USERS This reproduction is the best copy available. UMI fRAMSLOCAflOK OP CARBOHYDRATES IM SUSM B£ETS By Oliver Andrew Leonard A Thesis Suiteiitted to the (h^aduate Faculty for the Degree of DOCTOR OP PHILOSOPHY Major Subject - Plant Physiology Signature was redacted for privacy. Signature was redacted for privacy. Ma Signature was redacted for privacy. Dean of C^aduate College Iowa.--College UMI Number: DP12818 INFORMATION TO USERS The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleed-through, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. 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Box 1346 Ann Arbor, Ml 48106-1346 fABLE OP OONTEKT8 Page IN-mOlJOCflOR k LIfSRAfUBS 6 MAfERIALS AHD METHODS 12 Field colleotloas * 12 Experiments with Detached Leevea Xk Experlmeats on the Reversal of Traaeloeatloa 15 iBTertase Studies 16 Methods of Ghefflleal Analyses 16 Preliminary treatments 16 Sugar estlaatlOB 17 Polysacoharide estiaatlons 19 SXPERIHEMfJUL DAfA 21 Microohealcal Studies 21 Photosynthesis 22 franslocatioa 29 normal transport 29 Reversal experiments 51 Gradients In etiolated leaves 63 Transformation of Sugars 67 Invertase Activity 72 T5C.7 7 -> Page DISCUSSIOH ....... 75 SlJMMAaX 79 AGEMOWLSBOMEHf S $J LITSHAflIRE CITSB ..... •if- IHTRODUCflOS fhB preseat report eovere the i^sloXoglcaX piiases ©f a series of investigatioas oa tfee proi2uotioB of sugar beets in Iowa. It is iateaded to clarify the basle physiology of tlie beet plaat and to aid la tbe laterpretatioa of patbologlosd aad oultaral studies* la a plaat wdose oosm^eial Importaaoe depeads upoa its siigar eonteat, problems of photosyatJiesle, translocatloa sad storage are obviously iaportaat, aad l^e relatioa of tlie four iaportaat oarbobydrates of tlbie sugsr beet, suoroae, fruotose, glucose aad dextria, to these processes has beea the objeet of the laTestigatioa. The llteratux*e oa the sugars la the leaves aad roots is Toluolaous, but oaly a small fractioa of the mri. is related to photosyathesis, taraasloeatioa, traasforaatloa aad storage* Some of the older worlfe was fouad to be la aeed of relavestl- gatloa be cause of the methods used aad beoauae of laoomplete- aess* Previously, there had beea little effort expeaded ia deteralalag the factors which laflueaoe the reduolag sugar aad sucrose levels ia blades. Certala idiases of traaslocatioa, aad the latereoavertibllity of gluoose aad fructose ia sugar beets, as well as plaats ia geaeral, are also iffiperfeotly uaderst^od. -5- In tlie llterato'e one finds some information on tlie dis­ tribution of inrertase within the sugar beet plant^ tmt less is found on its activitj* In the present studT, the invert- aee aeti-rity of different parte of the plant was InTestigated and sueh data used in interpreting the synthesis and hydrolysis of suorose in plants. Ihe inrertase aotiTity of other leaves was also studied for comparison wit^ the beet. The sugsii* beet is better suited than most plants for certain phases of carbohydrate study, the three sugars, glucose, fructose, and sucrose, along with dextrin lAat is soluble in 10 per cent alcohol, are the important carbt^drates involved in this staady- Ifextrin not soluble la 10 per cent alcohol but soluble in hot water, and starch are only present in minute quantities ^d were not definitely detected by aa^ro- chemical means. LifsaATiai A T&wi.em ot the llterati^re on tii® photoejiit^esla and- the traasforfflatlon of sugars In plants may be found la a ree«at paper Ht«Mia (27)- Mason and Phillls (25) and Curtis (11)! have brought the llteratau:*# on transloeatlon pretty well up to date. In a general the author (19)» also, has reviewed the literature on the same subjeet. In this revievy only that sin^ar beet work whioh has a particular bearing on the present poroblea will be referred ^ and will be dlsouseed in clironological order. Qlrard (1?), in published the results of his studies on the chemical composition of leaves and roots of sugar beets. In the leaves, sucrose was found ^ fluctuate more between day and night than the reducing sugars. At night, sucrose was sometimes observed to be twice as great as it was the next morning, iriiile the reducing sugars were sometimes the ssiae. He concluded from this that sucrose Is the first laroduct of photosynthesis and is moved to the root as sueh. However, Sirard analyzed both the midribs and the blades together. The hi^ peroentage of reducing sugars in the midribs undoubtedly masked the diurnal variations which occurred in the blades. He was unable to detect the presence of reducing siiigaa»s in the roots. Maoguenne (23) in 1895* contrary to {Jirard, believed that the redueli^ sugars were the first prodaots of photosynthesis and that they migrated to the roots In that fora, and were there condensed Into 8!i«»:*ose. I^lndet (go) In 1SK30 InYeBtlgated the proportion of glu­ cose to fructose la different parts of the leaves. In the early stages of ^owth <Jfuly|, gluoose usually exceeded fruo- tose In the blades, while in the petioles^ fructose was found to be low in comparison to glucose. Llndet believed that the excess of fructose in the leaves was due to glucose being eon- suaed in the tissues by respiration faster than fructose, fhe low fructose values for the petioles were believed to be due t© fructose being used more easily than gluoose in the formation of new tissues, StrslDesoh in 1907 (33), wiploylng sicroehesical aethods, found glucose as the only sugar in the mesoplqrll cells of the sugar beet. IHae migration of glucose into the veins was followed by the appeiranoe of fructose therein and lat^ the formation of sucrose. He believed that glucose was the first product of photosynthesis and from it fructose was fonsed. In the veins and petioles, glucose and fructose were oondensed to tosm Bucx^se and translocated to the roots la that form, Pe^o la 190s {28}, also fro® aicrochemical data, concluded tiiat the siev« tubes contained the greatest amount of sucrose. la 19C9 i^bertson, Irvine, and Dobson {30) studied the distjributioa of enzyaes in the blades, petioles, and roots of the sugar beet, *13iey found that invertase was present in Xhm blades and petioles but was absent from the roots. They be­ lieved that Invertase synthesized as well as hydrolyzed sucros# and, therefore, concluded that sugars were translocated to the root in the form of sucrose. Stephanl in 1911 (32) supported this view. Ruhland {31) in 1911 held that in the sugar beet the sugar migrates in the leaves, not as sucrose, but as reducing sugars and perhaps mainly as fructose, fhe reducing sugars are con­ densed into sucrose upon entering the roots where they are stored and fro® whence they cannot be moved until drara upon by growth the following year. The reducing sugars at times actually decreased from the apex to the base of the petiole. The cells of the leaves were said to be permeable to fructose, glucose, sucrose, and more or less to all the sugars tested (five per cent sugar solutions). Starch was formed in the leaves when any of these sugars were supplied externally. Sampbell in 1911 (^}, working on the mangold plant which, like the sugar beet, is a variety of Beta vulg;aria L., suggested that the reducing sugars were the first carbohydrates to be formed as soon as daylight began, A little later the sucrose curve began to rise, and later still the starch curve. The sucrose curve did not appear to rise before the reducing sugars had reached their fflaxiaura, which they maintained throughout the period of illumination. Similarly, the starch did not seem to rise until sucrose had reached its maximum. The young leaves had a much higher level of reducing sugars -9- the old lea?es, but the sucrose eonteot was about the same, fhe fraetioa reported as •starch*, wst probably dextrin rather than et^efe. in 1916, PaTls, and Sawyer (13)f published the fflost complete WOTIS. whioh had yet been done en Beta -yulRsria L. Soa© of the Ir conelusions werei (1) Starch ie absent froa the leaYes, exeept in rery early stages of growth before the root has undergone appreolabls enlargement, (2) Maltose is absent at ail stages of growth, In the midribs sad petioles the heatoses are always greatly in excess of sucrose and vary greats between day and ni^t, and throughout the season, whereas sucrose remains relatively constant.