Interactions between Gibberellic Acid, Ethylene, and Abscisic Acid in Control of Amylase Synthesis in Barley Aleurone Layers

Gibberellic acid-induced α-amylase synthesis in barley (Hordeum vulgare L.) aleurone layers was inhibited by abscisic acid, and the inhibition was partly removed by additional gibberellic acid alone and by ethylene alone. Together additional gibberellic acid and ethylene almost eliminated abscisic acid inhibition of amylase synthesis. Time course studies of these phenomena showed that the effect of abscisic acid, ethylene, and varying concentrations of gibberellic acid on the course of amylase synthesis were either to speed up or slow down the whole process and not to affect the lag phase or the linear phase separately. The data are discussed in relation to previous studies of abscisic acid-gibberellic acid interaction.