CHAPTER 8 



Plant Cell Membranes 



Wanda K. Farr 



The studies of the formation and structure of plant cell membranes, 

 which were carried out at Boyce Thompson Institute for Plant Research, 

 Inc. over a ten-year period (1930-1940), had their origin in the earlier work 

 of Clifford H. Farr and Wanda K. Farr on the cell divisions of pollen 

 'mother cells,^- ^ and the growth of root hairs in solutions.^- ^ In the con- 

 sideration of these two aspects of growth, i.e., cell division and cell enlarge- 

 ment, the problems relating to the elaboration of cell membrane materials 

 in the living protoplasm, as well as those relating to the methods of forma- 

 tion and microscopic structure of mature membranes, were constantly in 

 evidence. In 1929 the Division of Cotton Marketing, United States Depart- 

 ment of Agriculture, provided the facilities for an intensive study of the 

 third major aspect of growth, cell differentiation. The project outlined 

 dealt specifically with the cotton fiber, and particular emphasis was placed 

 upon the study of the formation and structure of its cell wall. The thin, 

 colloidal cell membrane of root hairs, the more or less general absence of 

 cellulose, and the lack of pronounced microscopic structural differentiation 

 in the walls of many of them had rendered them of limited value for the 

 study of the so-called "cellulose" fibers of industrial importance. The 

 cotton fiber membrane, with its large accumulations of doubly refractive 

 cellulose and microscopically visible fibrillar structure, promised greater 

 advantages. 



For more than a year the work was carried out in Washington, D. C. and 

 at Clemson College, S. C. Late in 1930 the headquarters for this research 

 was transferred from Washington to Boyce Thompson Institute. Labora- 

 tory space and facilities were provided by the Institute for Mrs. Farr and 

 .one assistant. Continued cooperation Avith Clemson College afforded field- 

 grown cotton fibers of various stages of development. Methods of growing 

 the cotton plants to maturity in the Institute's greenhouses were soon 

 worked out; they provided one of the most important steps in the detailed 

 studies of cotton fiber development which followed. At this same time a 

 cooperative arrangement was made with the x-ray laboratory of the Depart- 

 ment of Chemistry, University of Illinois, in order that this more recently 

 developed technique might be added to the microscopic and chemical tech- 

 niques already in use. 



260 



