Metabolism of [3H]Gibberellin A20 in Light- and Dark-grown Tobacco Callus Cultures

Abstract

The growth of tobacco callus in culture (previously shown to contain GA-like substances), and its ability to metabolize [3H]-GA20 were examined. Growth rates, in the presence and absence of exogenously applied GA, were examined in light and dark conditions. Dark-grown callus grew at a much faster rate than light-grown and [3H]GA20 was metabolized much more rapidly in darkness than in light. [3H]GA1 was identified by combined GLC/mass spectrometry as a major product of [3H]GA20, and was a more potent promoter of tobacco callus growth than GA20.