Guilliermond - Atkinson 



— 88 



Cytoplasm 



MOTTIER (1918) finds that plant cells containing chlorophyll 

 constantly enclose plastids and chondriosomes which stain in the 

 same way. In meristematic cells of phanerogams he finds these 

 two categories of elements have the same form and are very diffi- 



>P 



Fig. 56. — A. Development of chloroplasts in aerial root of Chloro- 

 phytum Sternbergianum (After Meves). 1, meristematic cell, the 

 chondriosomes represented by chondrioconts (P) only, the granules (Gm) 

 MEVE3 believes to be metabolic products; 2-5, successive stages in the 

 transformation of chondrioconts into chloroplasts, granules unchanged. 

 B. Development of amyloplasts in pea root (After Mottier). 1, meri- 

 stem, amyloplasts (P) shaped like chondrioconts, mixed with small, 

 filamentous or granular elements (C) the only elements which Mottier 

 believes to be chondriosomes; 2, mature root cell, amyloplasts (P) form- 

 ing starch, the chondriome (C) unchanged; 3, detail, amyloplasts (P) 

 forming starch (A), division figure of chondriosome (C) at Cd. 



cult to differentiate, still the plastids would always be recognizable 

 because of their slightly greater size. The two classes of elements 

 correspond to permanent components of the cell, incapable of aris- 

 ing de novo and multiplying only by division. Nevertheless this 

 American investigator considers them as radically different forma- 



