INTERACTION OF JASMONIC ACID WITH SOME PLANT-GROWTH REGULATORS IN THE CONTROL OF APPLE (MALUS-DOMESTICA) EMBRYO GERMINATION

Embryos isolated from dormant apple seeds were treated with jasmonic acid (JA), gibberellin A(3) (GA(3)), abscisic acid (ABA) and hydrogen cyanide in darkness and in light. The chemicals were present in the culture medium continuously and simultaneously or applied for 2 days and in different sequences. All treatments stimulated embryo germination except ABA, which was strongly inhibitory. Additive effects of JA with light and with GA(3) on embryo germination were observed, whereas ABA interacted synergically with JA, HCN and light. ABA and GA(3) were most effective when applied early during embryo incubation, but the late JA treatment was more stimulatory. It is concluded that JA does not act on the regulatory pathway that is initiated by light and which leads to embryo germination through gibberellin accumulation and alkaline lipase activation. ABA and HCN appear to be involved in the control of this pathway. JA and ABA may be involved in the control of alkaline lipase activity, independently of this regulatory chain.