PLANT CELL MEMBRANES 



261 



Figure 97. Median cross-sections of bolls of Gossypium hirsutum L. showing daily- 

 increase in size from the date of flowering to the twenty-first day of development (1 H X). 



General Studies of Cotton Fiber Growth 



The results of the earhest work were of a more general nature, dealing 

 with the origin and early stages of elongation of the cotton (Gossypium 

 hirsutum L.) fiber ^^ (Fig. 97) ; cell divisions in the epidermal layer of the 

 ovule subsequent to fertilization " (Fig. 98) ; structural features of the wall 

 suggested by x-ray diffraction analyses and observations in ordinary and 

 plane-polarized light ^^ (Fig. 99) ; and fiber abnormalities as related to 

 varietal differences and to the density of the fiber mass within the boll.^^ 



Large numbers of dividing cells in the epidermal layer from the date of 

 flowering to the twelfth day follomng showed that cell enlargement is not 

 alone responsible for the tangential extension of the epidermal layer of the 



