Chapter VIII 



81 — The Ghondriome {cont'd) 



The very beot material for the study of living cytoplasm is to 

 be found in the epidermal cells of flowers and various organs of 

 the monocotyledons, those of Iris and tulip among others, as well 

 as in the bulb scales of Allium Cepa, which will be taken up later, 

 and in the Saprolegniaceae which have just been studied. On these 

 forms we have been able to make the most accurate observations of 

 the chondriosomes that it has been possible to make up to the 

 present time. 



We have been able to show, by a comparison of these observa- 

 tions with those on fixed and stained cells, that the mitochondrial 

 methods preserve the cytoplasm and its morphological constituents, 

 the chondriosomes and plastids, in a manner as faithful to the 

 form they present in life as it is possible to have it done. These 

 observations permitted us, 

 also, to specify the histo- 

 chemical and histophysical 

 characters of the elements. 

 This will be taken up later. 



We have studied the 

 chondriome very accurate- 

 ly during the formation of 

 the embryo sac and of pol- 

 len grains in the Liliaceae 

 and, in particular, in Lili- 

 um candidum. In the young 

 ovary, all the cells of the 

 nucellus present a chondri- 

 ome made up of a mixture 

 of chondrioconts and of 

 mitochondria. The embryo 

 sac, which arises from a 

 cell of the nucellus, first 

 shows a chondriome simi- 

 lar to that of other cells of 

 the tissue, then, in the course of its differentiation, at the mo- 

 ment when synizesis begins, it is observed that a part of the 

 chondrioconts thicken and form small swellings on their long axes. 

 These grow little by little, often detach themselves from the chon- 

 driocont in which they rise by rupture of the thin portions which 

 connect them, then enlarge greatly, and take on a crystalline ap- 

 pearance. This seems to be due to the production in their interior of 

 protein crystalloids. These plastids, which we have called proteo- 

 plasts, because of their ability to elaborate protein, then appear to 

 be digested in the cytoplasm and their protein is thus utilized as a 

 reserve product. In the synergids, the egg and the antipodal cells, 

 on the contrary, no elaboration of protein is noted and the chondri- 

 ome remains about as it is in the embryo sac at the beginning of 

 differentiation, except for the appearance of small granules slightly 

 larger than the other elements of the chondriome. These granules 

 are the leucoplasts. In the tulip no proteoplasts are observed and 



Fig. 48. — Development of chromoplasta in cells of 

 the petals of Iris gervianica, 1, very young stage 

 showing colorless chondriocont-shaped plastids and 

 granular chondriosomes; 2, the starch-bearing plas- 

 tids begin to fill with xanthophyll; 3, the starch is 

 absorbed as the chromoplasts increase in size; 4, 

 mature cell with variously shaped chromoplasts, most 

 of them showing vesiculate swellings. 



