Wjf / 



/ \ . ". r 



/ 



/ ? 



•^" / 



H) 



Vf/ 



■\ 



erW 



/ 



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/, 



N 



Fig. 9. This shows an early stage in the development of the cell plate between 

 two daughter cells of onion root meristem. The telophase nuclei are at A^ and a new- 

 nuclear envelope has just reformed {ne). Long slender profiles of the ER, present in 

 the interzone, appear noticeably shorter toward the plate region {cp), and at this 

 level they reticulate and intermingle from the two sides to form a dense, irregular 

 lattice of tubules. Within this structure, which has its origins in the marginal 

 extensions of the ER, the early pectin vesicles of the plate first appear (see Fig. 10) 

 for later stage). These grow in number and size and eventually fuse to separate the 

 two daughter cells. (From Porter and Machado, i960.) 



