Guilliermond - Atkinson — 82 



Cytoplasm 



the chondriome, consisting of a mixture of chondrioconts and mito- 

 chondria, undergoes no modifications during the development of 

 the embryo sac^ (Figs. 49, 50, 51, 52). 



In the sporogenous cells of the pollen grains of Lilium can- 

 didum, the chondriome is seen clearly as short rods and granules. 

 In the pollen mother cells, only mitochondria are to be found. 

 Beginning with the period of synizesis, some of these mitochondria 

 which are to become amyloplasts, undergo a slight increase in size, 

 then, at the time of the heterotypic mitosis, they elongate into 

 chondrioconts and afterwards, in the pollen grains, break up into 

 mitochondria. The remainder of the mitochondria are unchanged 

 from the beginning. When the pollen grain is mature, only gran- 



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n 



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Fig. 49 (left). — Embryo sac of LUium candiduvi at the 

 beginning of differentiation. X 1500. Regaud's method. 



Fig. 50 (right). — Formation of proteoplasts in the embryo 

 sac of Lilium candidum at the end of the second mitosis. Regaud'a 

 method. 



ular mitochondria are found, among which a few larger than the 

 others elaborate compound starch grains. 



Other investigators of the development of the chondriome dur- 

 ing the formation of pollen in other plants have produced data 

 more or less analogous (WAGNER, Mascre, Krjatchenko-Douze, 

 Prosina, Mrs. Luxemburg, Krupko, Miss Py). Recently there 

 has appeared Lewis Anderson's very good work on the develop- 

 ment of pollen in Hyacinthus orientalis. Investigations of NlCO- 

 LOSi-RoNCATi, Wagner, and others have shown that the chondrio- 

 somes in the spore mother cells of some species may collect in a 

 compact mass which surrounds the spindle as a sort of mantle dur- 

 ing the heterotypic division and divides (chondriocinesis) at the 

 same time as the nucleus. The significance of this grouping of 

 chondriosomes is not clear and one wonders if it does not corre- 

 spond to an alteration. 



Chon(iriosomes have been observed in all the cells of the em- 

 bryo before the maturation of the seed and in the seed in the dor- 



"LEWI3 Anderson finds this is also the case for the embryo sac of the hyacinth. 



