Abstract: Soybean (chilling-sensitive) and pea (chilling-insensitive) seeds imbibed at 25℃ or 5℃ for 4.5h, and hypocotyls were removed, fixed nd examined for detecting the effect of temperatures during imbibition on membrane structures, It was shown that plasma membranes and external membranes in mitochondria in both seeds had even repaired their continuity. When the seeds of the two species germinated at 25℃ for 6 days after imbibed at 5℃ for 3h, parts of plasma membranes in hypocotyl cells were brokendown and sunken, there were a number of undegraded lipid bodies and protein bodies, in particular, the inner crista in mitochodria in soybean seed nearly failed to develop, and there were few Golgi bodies and rough ER in contrast to the controls and peas. It is suggested that it may be an important cause of imbitional chilling injury that reorganization of biomembrane structures and functions and the Junctional and structural integrity of mitochodria in particular were imbibited due to low temperature during imbibition.

Key words: Soybean, Pea, Seed, Imbibition, Temperature, Ultrastructure