Elongation of the cotton fiber PDF
Preview Elongation of the cotton fiber
NOTE TO USERS This reproduction is the best copy available. ® UMI Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ELONGATION OF THE COTTON FIBER by Joseph Charles O’Kelley A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of The Requirements for the Degree of DOCTOR OF PHILOSOPHY Major Subjeoti Plant Physiology Approved! £x £tCL ,., Dean of Graduate College Iowa State College 1950 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. UMI Number: DP12887 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. ® UMI UMI Microform DP12887 Copyright 2005 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48106-1346 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. TABLE OF CONTESTS Pag© introduction....................................... 1 REVIEW OF LITERATURE................................. 3 MATERIAIS AND METHODS................................. 19 Materials . . . . . . . . ............... . . . . . 19 Tissue Cultures . . . . * ............ . ......... . 19 Growth Measurements of Bolls and Fibers.............. 20 Cell Wall Structure ........... 21 Carbohydrate Determinations . . . . . . . . . . . . . . 24 Nitrogen Determinations ................. 26 EXPERBENTAL RESULTS .....................* ........ 29 Growth Measurements and Rates of Fiber Growth . . . . . 29 Structure of the Fiber Wall . . . . . . . . . . . . . . 49 Chemical Changes in Developing Fibers.......... ♦ . 60 Carbohydrate Change© . . . . . . . . . . . . . . . 60 Changes in Nitrogen Content of Cotton Fibers ... 74 DISCUSSION............................ SI s m w m .......................... 89 LITERATURE CITED................. . 91. AC«5KIUSG®NTS .................................. 97 T97<? V Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. IOTHODTJCTXOH Cotton fiber growth deserves study not only because of its economic importance, but also became it is in many ways better suited than any other plant material for use in investigating the processes of ceil elongation. Cotton fibers occur within the boll as an essentially homogeneous tissue and can be easily separated from the other tissue of the seed and boll. Since the fiber origi-* nates and ends as a single cell, elongation can be studied free of the complications that arise in the study of most plant tissues, in which cell division occurs along with elongation. Primary and secondary wall formation are distinctly separate processes in the cotton fiber. Both continue for a relatively long period, making possible studies that are not easily carried out with more rapidly growing and maturing tissues, Finally, the great elongation of the fiber makes it an excellent subject for study. Previous studies of cotton fiber development have dealt mainly with secondary wall formation, the differentiation phase of growth* The elongation phase lias received much less attention. For this reason this investigation deals primarily with fiber elongation. In certain cases, however, the study was extended to include differentiating fibers when such action appeared desirable. The present study proceeded along three related lines of investigationi Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 1* Bates of fiber elongation and factors affecting elongation rates* 2* the structure of the cell wall during cell elongation* 3* Changes in the carbohydrates and in the nitrogen compounds of developing fibers* Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. REVIEW CF LITERATDRE The use of cotton for the wearing of cloth appears to hare originated in India at such an ancient time that it preceded written records of human life* Although cotton has been cultivated for many centuries, almost all of what is known concerning the growth of cotton fibers has been discovered in the last fifty years. In the latter part of the nineteenth century attention was directed toward chemical and physical studies of nature cotton fibers and agronomic problems involved in the cultivation of cotton. Intensive programs of cotton breeding and studies of cotton diseases were carried out, while the physiology of the plant and particularly the development of the fiber were largely ignored. The elongation phase of cotton fiber growth was imperfectly known at the turn of the century. What was known of it was reviewed by Evans (1896), At this time it was recognized that the fiber appears a con siderable time before the seed is full grown, and that it commences as the development of a cell on the surface of the ovule, Ivans reported the method of growth, as described by Bowman (1882), to be by the successive linear development of cells, the and walls of which were believed to be absorbed until an elongated single cell was produced. This concept of the growth of the fiber was corrected by Bowman (1998), who determined that the fiber consists of a single elongated cell, continuous throughout its own length, and that it originates as a single call. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Kbowledge of the origin and early growth of the cotton fiber remained in tide incomplete state until the intensive studies of Balls in Egypt. Balls (1912) described the development of the fiber in considerable detail. Be discovered that the fibers begin develop ment before fertilization is completed, by radial growth of the epi dermal cells of the seed coat, that the young fibers at once assume their mature diameter, about twice that of the unaltered epidermal cells, that the nucleus lies at the tip of the swelling at first and after the third day of growth moves to the middle of the cell, whore it remains alive until the bell opens. He reported that the growth of the fiber is at first confined to elongation, and that the boll attains almost full size before any secondary thickening of the fiber wall occurs. He also believed that the fiber attains its final length before secondary thickening begins, but did not establish this point at this time. Balls found the elongation period of the cotton he studied to be about twenty-five days, approximately half of the total maturation period* The time of origin of the lint hairs was a subject of controversy for several years, beginning with the observation of Balls (1915) that the density of lint cm the seed is determined the first day after ferti- / lization, that lint hairs do net originate after this time. Singh (1931), studying the early stages of fiber development, found that on the day the flowers open, epidermal cells of the ovule bulge out in the form of tiny balloons, and that these are sparsely distributed on the epidermis of the Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ©role* He observed that as the fertilized ovule grew the epidermal cell number increased} that thirty-six hours after fertilization fibers occurred in different stages of development, and that forty-eight hours after fertilization almost all epidermal cells were involved in the formation of fibers. Gulatl (1930), making calculations of the number of hairs on one-day-old ovules and mature seeds, found a mean value for the number of hairs on one-day-old ovules of 2,208, and a mean value for the number of hairs on mature seeds of 14,809, He also observed epidermal cells in the process of division in ten-day-old ovul.es, and observed growing fibers of greatly different lengths in close prcxdmity to one another. He concluded, as did Singh, that fibers continued to originate after the day of flowering, Parr (1931), on the basis of observations similar to those of Singh and Gulati, concluded that some fibers were formed from cells arising as the result of cell divisions in the ovule epidermis subsequent to fertilization of the ovule, Darrltt (1932), in a criticism of the findings of Gulatl and Parr, did not confirm the occurrence of mitotic division of epidermal cells in ovules seven days after flowering. Additional studies by Parr (1933) on young ovules sup ported her original conclusion, Ayyar and Ayyangar (1933), Gulati (1934), and Sheffield (3-936) gave further evidence to support the conclusion that fibers may be formed after the day of fertilization, Anderson and Kerr (1938), after studying early growth of the fiber, expressed the opinion that the fibere originating within two or three days after the date of flowering become the commercial fibers and that others, which may originate as late as ten days after flowering, are the linters of the seed, Barritt Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
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