Guilliermond - Atkinson 



— 104 — 



Cytoplasm 



the vital stains for chondriosomes (Janus green, Dahlia violet, 

 methyl violet, etc.) the chloroplasts do not behave like the leuco- 

 plasts, in that the chloroplasts are not stained as long as the cells 

 are alive. On the contrary, as Strugger has shown, living chloro- 

 plasts are stained by rhodamine B which, at a sufficient concen- 

 tration, gives them, with time, a very characteristic yellowish color 

 in cells which show cytoplasmic currents and which remain alive 

 for a very long time. (Rhodamine B also stains the chondriosomes 

 and leucoplasts but very faintly.) The chloroplasts are distin- 

 guished from other plastids by their property of reducing silver 

 nitrate. This property was noted first by Molisch and, as we have 

 seen earlier, is manifested only in living cells. Ruhland and 

 Wetzel found it possible, with this reaction, to demonstrate the 

 presence of chloroplasts in the chondriosomal state in generative 

 cells of Lupinus luteus and of some other plants. Gavaudan in his 



? 3 ' ^-^ 4 



Fig. 72 (left). — Chondriome of antherozoids of Adiantum capillus-Veneriii. 

 1, 2, antheridial initial. 3, 4, sperm mother cell. 5, 6, stages in the formatioQ 

 of the antherozoid. Regaud's method. (After Emberger). 



Fig. 73 (right). — Behavior of the chondriome during the life cycle of a fern, 

 I. leaf; starch-forming chloroplasts and chondriosomes. 2-3, formation of spores: 

 decreasing activity of plastids. 4, spore mother cells; inactive plastids indistinguish- 

 able from chondriosomes. 5, mature spore; plastids become active. 6, prothallus: 

 starch-bearing chloroplasts. 7, 8, sexual cells; second cessation of activity of 

 plastids. 9, egg; homogeneous chondriome. 10, developing embryo; certain chon- 

 driosomes secrete starch. 11, 12, adult plant; 11, amyloplasts of the root. 12. 

 chloroplasts of the leaves. (After Emberger). 



study of the hepatics claimed that this property is common to all 

 plastids, even those lacking in chlorophyll, and considers it a means 

 of distinguishing plastids from chondriosomes. But our later re- 

 search, as well as that of Gautheret and of Mirimanoff, did not 

 confirm this assertion and proved that plastids without chlorophyll 

 do not reduce silver nitrate in living cells any more than do chon- 

 driosomes. This property which chloroplasts have of reducing 

 silver nitrate in living cells has nothing in common with the black 

 coloration of the plastids and chondriosomes in cells treated by 

 Alvarado's modification of Rio-Hortega's method, or with that 

 sometimes taken on when they are impregnated with silver (Golgi 

 method). It does, however, explain why Pensa found that only 

 the chloroplasts were stained when he treated living tissue with 

 Golgi's technique (silver impregnation). 



