Cytokinin modulates catalase activity and coumarin accumulation in in vitro cultures of tobacco.

摘要

The effect of cytokinins (CKs) on catalase activity in tobacco cultured in vitro is demonstrated. The catalase activity observed in suspension-cultured cells decreased slightly during the first hour of CK treatment and increased thereafter to doublethe level detected in untreated cells. In contrast to these results, catalase activity was inhibited in shoot cultures in which the endogenous levels of CK were elevated by the introduction of the isopentenyltransferase gene or by an exogenous feeding of CK to the cultures. The catalase inhibition correlated with an accumulation of scopolin, an inducible coumarin. It is concluded that CK modulates (directly or indirectly) catalase activity. The inverse relationship that was always found between scopolin accumulation and catalase activity is discussed in terms of vitrification and habituation.