Abstract: Relevant effects of ethylene and Ca2+ on germination of lettuce (lactuce sative L.) seeds were investigated. It was shown previously that lettuce seeds were highly sensitive ro temperatures. More than 70% of seeds germinated at 22℃, but they ceased to germinate at 25℃. 40%–50% of seeds could be induced to germinate after imbibition with 400 ppm exogenous ethylene for 3 days at 25℃. The amounts of endogenous ethylene liberated at 22℃ were much greater than those at 25℃. Ethyleneglycol bis NN tetraacetic acid(EGTA, Ca2+ specified chelating regent) La3+, Co2+ and chlorpromazin(CPZ, calmodulin antagonist) could be used ant only to inhibit germination at 22℃, but also to inhibit germination induced by ethylene at 25℃. Although La3+ and CPZ inhibited seed germination, they could not repress the production of ethylene at 22℃. It was suggested that Ca2+ and CaM affected the induction response of ethylene to lettuce seed germination, but had no effect on ethylene liberation. Co2+ could be applied to inhibit the action as well as its production of ethylene.

Key words: Lettuce seeds, Ethylene, CA2+, Calmodulin (CaM)