Chapter VIII 



— 71 



The Chondriome (cont'd) 



Without knowledge of Pensa's work, Lewitsky, a student of 

 Strasburger, was working at the same time with mitochondrial 

 technique (method of Meves). Lewitsky (1911) showed in the 

 bud of Asparagus officinalis that the chloroplasts are built up from 

 minute elements looking like the chondriosomes of animal cells. 

 This investigator concluded therefore that the plastids, contrary 

 to the opinion of SCHIMPER, do not keep their individuality but 

 arise from chondriosomes which LEWITSKY considers originate, in 

 turn, from a differentiation of the cytoplasm. 



At the same period (1911) and a little later, in cells of 

 plants belonging to very diverse groups (phanerogam seedlings, 

 nucellus, embryo sac, pollen, asci of Pustularia vesiculosa), we 

 were demonstrating by Regaud's method, the existence of chon- 



o>®^^ 



m 



5 



a) 



Fig. 34. — Various types of starch formation. 1, ■within mito- 

 chondria in young potato tuber; 2-4, compound grains within 

 chondrioconts in the meristem of a young root of castor bean; 

 5-7, compound grains within chondrioconts in bean root: 8, within 

 fusiform leucoplasts surrounding the nucleus; 9, leucoplasts show- 

 ing successive stages in starch formation. 8, 9, from the root 

 of Phajus grandifolius. Regaud's method. 



driosomes quite similar in form, as well as in histochemical be- 

 havior, to those of animal cells. Our investigations led us to 

 consider, contrary to the opinion of Lewitsky, that the chondrio- 

 somes are permanent organelles, being transmitted by division 

 from cell to cell and incapable of forming de novo. We were 

 demonstrating besides, by a study of the plumule of barley, that 

 chloroplasts arise by the differentiation of some of the chondrio- 

 somes in cells of the meristem. Finally by a study of the potato 

 tuber and of roots of various seedlings, notably those of castor 

 bean, we were able to prove that starch never forms in the cyto- 

 plasm but is always the product of the activity of chondriosomes. 

 Our later investigations (1912-1923) as well as those of Pensa 

 (1912) and Lewitsky (1912), followed by many others, confirmed 

 these facts and if interpretations still differ, it nevertheless seems 



