Ultrastructures of Plastids in Embryos ofPicea ExcelsaL. andLarix DeciduaL. During Germination in Darkness

Abstract

SUMMARYPlastid ultrastruetural modifications of cotyledons of embryos of Larix and Picea in the various stages of germination of seeds in dark conditions are studied and compared to the content, already studied, in chlorophyll pigments. 1) In dry seeds, whose embryos are chlorophylless in both species, proplastids in embryos of Picea show vesicles and tubules of various length, sometimes winding, while proplastids in embryos of Larix show only vesicles of various size.2) In swollen seeds of Picea, proplastids show some small vesicles, tubules of various length, sometimes still winding, and small starch grains. In swollen seeds of Larix proplastid stroma is occupied by many vesicles and more or less long tubules, sometimes showing some organization, besides by small starch grains. The chlorophyll content in swollen seeds both of Larix and Picea, is remarkable.3) In germinated seeds of Picea (with rootlet long 10 mm.) grana are sometimes formed, but oftener the stroma is occupied by vesicles arranged close ...