Abstract
Naturally occurring 4′-dihydrophaseic acid (DPA) has been isolated from mature, non-imbibed bean seed. The concentrations of abscisic acid (ABA), phaseic acid (PA) and DPA in the seed were estimated to be 0.06, 0.11 and 5.95 mg/kg dry wt., respectively. The results suggest that DPA is a major inactivation product of ABA in this tissue. The possible pathway from ABA to DPA is discussed.