Regulation of abscisic acid metabolism in the aleurone layers of barley seeds.

The regulation of metabolism of abscisic acid has been investigated in the isolated aleurone layers of barley (Hordeum vulgare L.) seeds. The rate of conversion of abscisic acid to phaseic acid is enhanced by two to five-fold when the tissue is pretreated with 10(-5) M of this hormone. This enhancement can be observed with a pretreatment as short as two hours, and is prevented by transcription and translation inhibitors. The enhancement is accompanied by the appearance of new proteins which are induced by abscisic acid. It is suggested that some of these ABA induced proteins are probably involved in the conversion from abscisic acid to phaseic acid.