Dormancy regulation by morphactin in aerial tubers of Begonia evansiana.

The sprouting of aerial tubers of Begonia evansiana was promoted by treatment with morphactin. As with cytokinins, the promotion of sprouting occurred in both the immature and mature tubers. Unlike cytokinins, however, morphactin did not stimulate tuber enlargement. The sprout-inhibiting action of applied gibberellin (GA) was overcome by morphactin. The possible mechanism of the inhibitory action of GA is diseussed in relation to apical dominance.