Significance of Spermidine in the Initiation of Adventitious Buds in Stem Segments ofTorenia

摘要

When stem segments ofTorenia fournieriLind. were cultured in vitro, the initiation of adventitious buds, which is usually induced by cytokinin, was induced by application of polyamines, such as putrescine and spermidine. Addition of arginine had a slight inductive effect. When cyclohexylamine, an inhibitor of spermidine synthase, was added simultaneously with putrescine, induction of the initiation of buds by putrescine was strongly inhibited. However, application of the inhibitor together with spermidine had no effect on the spermidine-induced initiation of buds. The induction of initiation of buds by a cytokinin, by a calcium ionophore, by cyclic AMP, and by a phorbol ester, which was accompanied in each case by elevation of the levels of endogenous spermidine, was also inhibited by cyclohexylamine. These results suggest the involvement of spermidine in the initiation of adventitious buds in stem segments ofTorenia.