Submicroscopic Structure and Development of the Chloroplasts of Funaria hygrometrica and Bryum sp

Abstract

Freshly collected specimens of Bryum sp. (gametophyte) and Funaria hygrometrica (gametophtye and sporophyte) were used for the study of the fine structure and development of chloroplasts. The fully-developed chloro-plasts of both species are ellipsoidal. The chloroplasts are bounded by a well-defined dense membrane. The laminar systems within the chloroplasts have their double closed lamellae or discs arranged into stacks or grana. The stroma lamellae are merely extensions of grana discs which form some sort of a continuity between the grana. In general, the stacks of Funaria chloroplasts are more compact than those of Bryum. Osmiophilic globules occur in the chloroplasts of both species.
The development of chloroplasts of both species may be summarized as follows:
1. In the proplastids, vesicles and osmiophilic globules cccur.
2. The lamellae are formed locally by fusion of the vesicles.
3. The number of lamellae increased with size of the chloroplasts, and the lamellae form closed double membranes or discs.
4. The discs become arranged into stacks which indicate grana formation.
5. Osmiophilic globules are present at all stages and show an increase in size with the advance of development.