Influence de la température sur les membranes de sphérosomes de cellules méristématiques de luzerne

The radicular meristematic cells of Medicago sativa L., cv. Saranac, contain spherosomes 0.2–1.3 μm in diameter distributed throughout the cytoplasm. These organelles usually have a spherical shape, react positively with Sudan black and contain osmiophilic material. This material can be dissolved in ethyl ether – ethanol 2:1 but not in petroleum ether. In tissues fixed in different manners, from plants growing under different conditions, the spherosomes possess an envelope consisting of two unitary membranes. This envelope is in structural continuity with the endoplasmic reticulum. During senescence, membranes separate from spherosomes thus initiating the formation of one vacuole which surrounds this organelle. The spherosome dense material eventually undergoes degradation within this vacuole.