Plant Growth Regulation
Poljakoff-Mayber, A., Department of Botany, Hebrew University, Israel
Popilevski, I., Department of Ornamental Horticulture, Volcani Center, Israel
Belausov, E., Department of Ornamental Horticulture, Volcani Center, Israel
Ben-Tal, Y., Department of Ornamental Horticulture, Volcani Center, Israel
Oat seeds are susceptible to high temperature dormancy. Dormant grains do not germinate at 30°C unless afterripened, dry, for several weeks. Isolated embryos of dormant grains do germinate, especially if GA3 is added to the germination medium. ABA inhibits germination proportionally to the concentration applied and GA3 can overcome the ABA inhibitory effect. Measurements of endogenous ABA and several GAs revealed that the initial levels of ABA in dormant and non-dormant grains were quite similar. But, endogenous ABA in non-dormant seeds almost disappeared within the first 16 h of imbibition, while the amount in dormant grains had decreased by less than 24%. The level of GA19 in non-dormant seeds was higher, and GA19 appears to be converted to GA20 within the first 16 h. The GA20 was converted to GA1 at least during the first 48 h of the germination process. Both phytohormones thus appear to be involved in the germination process of non-dormant seeds. ABA first declines, while GA1 is produced during the first 16 h of imbibition to allow proper germination. In dormant grains the level of ABA remained high enough to prevent germination during at least a week and precursor GAs were not converted to GA1.
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Involvement of phytohormones in germination of dormant and non-dormant oat (Avena sativa L.) seeds
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Poljakoff-Mayber, A., Department of Botany, Hebrew University, Israel
Popilevski, I., Department of Ornamental Horticulture, Volcani Center, Israel
Belausov, E., Department of Ornamental Horticulture, Volcani Center, Israel
Ben-Tal, Y., Department of Ornamental Horticulture, Volcani Center, Israel
Involvement of phytohormones in germination of dormant and non-dormant oat (Avena sativa L.) seeds
Oat seeds are susceptible to high temperature dormancy. Dormant grains do not germinate at 30°C unless afterripened, dry, for several weeks. Isolated embryos of dormant grains do germinate, especially if GA3 is added to the germination medium. ABA inhibits germination proportionally to the concentration applied and GA3 can overcome the ABA inhibitory effect. Measurements of endogenous ABA and several GAs revealed that the initial levels of ABA in dormant and non-dormant grains were quite similar. But, endogenous ABA in non-dormant seeds almost disappeared within the first 16 h of imbibition, while the amount in dormant grains had decreased by less than 24%. The level of GA19 in non-dormant seeds was higher, and GA19 appears to be converted to GA20 within the first 16 h. The GA20 was converted to GA1 at least during the first 48 h of the germination process. Both phytohormones thus appear to be involved in the germination process of non-dormant seeds. ABA first declines, while GA1 is produced during the first 16 h of imbibition to allow proper germination. In dormant grains the level of ABA remained high enough to prevent germination during at least a week and precursor GAs were not converted to GA1.
Scientific Publication