EFFECT OF HIGH-TEMPERATURES ON GERMINATION OF PEA EMBRYOS (PISUM-SATIVUM L)

We investigated the action of prolonged and short-term heat shock on g ermination of pea embryos (Pisum sativum L.) under laboratory conditio ns. To this end, the testa was removed from surface-sterilized seeds a nd embryos germinated on water in open Petri dishes under different te mperature regimes. Maximum germination temperature is between 35 and 3 8-degrees-C. Germination is slowed at 35-degrees, is significantly sup pressed at 38-degrees, and does not occur at all at 40-degrees. The ti me of heat influence during the period of imbibition is the critical f actor for germination of pea embryos. The greatest permissible time of heat shock (40-degrees) is 8-10 h. After imbibition at 40-degrees for more than 10 h, cells of the embryonic axis are incapable of overcomi ng the unfavorable consequences of heat stress and unable to recover t he cellular metabolism needed for successful germination. Brief heat s hock (4-6 h) at any of the stages of germination does not prevent rene wal of growth activity, but slows development of the seedling, i.e., i t lowers germination energy.