Abscisic acid catabolism in light-grown and etiolated leaves of Hordeum vulgare l. cv. dyan

Abstract

Radioactive ( R,S)-abscisic acid (ABA), supplied via the transpiration stream to light-grown leaves of Hordeum vulgare in the light was catabolized more efficiently than in leaves of their dark-grown counterparts in the dark. The overall rate of ABA conversion into phaseic acid (PA) and dihydrophaseic acid (DPA) and the conversion of ABA into aqueous conjugates and 7′-hydroxy ABA were also greater in light-grown leaves. Treatment of etiolated leaves with glucose and sucrose enhanced ABA catabolism, suggesting that CO 2 assimilation is required for the efficient catabolism of ABA.