بررسي جنبه هاي فراساختاري در بذر يولاف وحشي

A STUDY ON ULTRASTRUCTURAL ASPECTS OF SEED DORMANCY IN WILD OATS

The structural differences between dormant and nondormant seeds of wild oats (Avena ludaviciana Durieu) were studied by light and transmission electron microscopy. Radial elongation of scutellum epithelial cells were observed in nondormant seeds after imbibition, compared with dormant seeds in which cells were completely compressed. Ultrastructural differences for example, dilution of cytoplasm, digestion of lipid and aleurone grains, enlarged endoplasmic reticulum, increase and assembly of polysomes and mitochondria, presence of a big vacuole were observed in nondormant seeds. Electron microscopy did not reveal such changes in dormant seeds. Nevertheless a lot of spherosomes, aleurone grains and some small vacuole were observed in the cytoplasm.