GuilHermond - Atkinson 



— 86 



Cytoplasm 



^M 



over, in the algae, bryophytes, and pteridophytes, all the interme- 

 diate stages between this chloroplast. of special form and chloro- 

 plasts such as exist in the phanerogams. Now the research of 

 Randolph has demonstrated in Vaucheria, which contains chloro- 

 plasts similar to those in phanerogams, that these chloroplasts are 

 found in all parts of the thallus at the same time as the chondrio- 

 somes. Our work on Spirogyra showed the chondriosomes to be 

 constantly present and distinct from the single permanent chloro- 

 plast which is characteristic of this alga. The work of Sapehin, 

 of SCHERRER, and of MOTTIER showed that in the bryophytes, too, 

 chlorophyll seems to persist in all stages of development, and that 

 all cells, even the egg and apical cell of the vegetative shoot, con- 

 tain both chloroplasts and chondriosomes. 

 There even exists, in this group, the genus 

 Anthoceros in which each cell contains 

 only one single crescent-shaped chloro- 

 plast adhering to the nucleus. Coexistent 

 with this organelle there are, however, 

 numerous chondriosomes. There can not, 

 therefore, be found in these plants any ge- 

 netic relationship between the chloroplasts 

 and the chondriosomes. It is to be added 

 that in centrifuging the cells of various 

 algae and cells of Elodea canadensis in the 

 process of division, BoROViKOV was able 

 to obtain cells without chloroplasts but 

 containing chondriosomes. He was never 

 able to observe in these cells any trans- 

 formation of chondriosomes into chloro- 

 plasts. These contradictory facts there- 

 fore must be explained. 



Rudolph (1911), Scherrer (1913), 

 Sapehin (1913), Arthur Meyer (1914- 

 1921) and NoACK (1921) protested, not 

 altogether disinterestedly, against the 

 new results obtained in the phanerogams 

 by mitochondrial technique which, at least in appearance, seem to 

 invalidate the classical theory. They did not hesitate to consider 

 the chondriosomes and plastids as inherently different formations. 

 To explain the phenomena in the phanerogams, Rudolph, Scherrer 

 and Sapehin report that in the meristematic cells of these plants, 

 the plastids and the chondriosomes stain in the same way with 

 mitochondrial technique. According to these investigators, the 

 plastids appear as small grains and the chondriosomes as rods or 

 filaments. Now, as the plastids divide actively, Rudolph, Scher- 

 rer, and Sapehin believe they become dumb-bell shaped and are 

 thereby confused with the chondriosomes (chondrioconts). But 

 from the moment that the cells differentiate, the plastids enlarge 

 and appear as large bodies which it is no longer possible to confuse 

 with the chondriosomes, since the latter keep their original form 



Fig. 54. 



Portion of a fil- 



ament of Vaucheria; division 

 figures of the chloroplasts 

 (C) and of the chondrio- 

 somes (M). (After Mange- 



NOT). 



