EFFECT OF HEAT-SHOCK ON MOBILIZATION OF PROTEIN DEPOSITS IN AXIAL ORGANS OF IMBIBING PEA EMBRYOS (PISUM-SATIVUM L)

We investigated the nature of changes in the polypeptide composition o f total protein of pea embryonic axes during normal and high-temperatu re imbibition. Significant changes occur in proteins of the axial orga ns during imbibition and the lag phase of germination at 28-degrees-C. One-dimensional SDS disk electrophoresis revealed about 20 polypeptid es with sharply lowered content at the outset of axial organ growth. H alf of these proteins degraded rapidly and disappeared during the firs t 8 h of embryo imbibition. The rest broke down more slowly and disapp eared gradually toward the outset of growth. Albumins were dominant am ong the rapidly decomposing proteins, while the slowly consumed protei ns were mainly represented by globulins. When embryos imbibed at high temperature (38, 40-degrees), no changes occurred in the polypeptide c omposition of axial organ protein. Thus, the metabolic development of pea embryo axial or-ans during the period preceding the outset of grow th was accompanied by active decomposition of their own protein reserv es. Heat influence at the initial stages of germination apparently ind uced metabolic changes inhibiting mobilization of storage protein depo sits in tissues of the axial organs. This presumably can be one of the causes of the adverse effect of high temperatures on germination.