Bean seeds were unable to germinate during their development which was characterized either by an increasing ABA content (expressed as ng ABA/seed) or by a fairly high and constant ABA concentration (expressed as ng ABA g−1 fr. wt). During seed maturation the mother plant induces a dormant state by depressing the ABA catabolism and keeping the endogenous ABA at a high level to prevent both the premature hydrolysis of starch (α-amylase activity) and the germination of the morphogenetically adult yet immature seeds. The depth of this induced dormancy is positively correlated with endogenous ABA concentration. Application of exogenous ABA to fully mature seeds, which contain no endogenous ABA and show a very active ABA catabolism, only prolonged the lag phase but had no influence on the further development of the α-amylase activity.