Effect of Photoperiodic Floral Induction on the Metabolism of a Gibberellin Precursor, (-)-Kaurene, in Pharbitis nil.

Pharbitis nil seedlings rapidly metabolized (-)-kaurene-17-(14)C administered to the cotyledons. Less than 20% of the radioactivity was recovered by extraction of the cotyledons on the following day. Of this the major metabolite was an unidentified acidic material which did not correspond chromatographically to any of the known gibberellins.Significant differences were observed between the radioactivity found in the buds of a group of seedlings subjected to photoperiodic floral induction and that in a noninduced group. In both cases almost all of this radioactivity was in the neutral fraction, but thin-layer chromatography of these fractions revealed that the induced group contained 2 or more labelled components which were either absent or present in lower concentrations in the noninduced group.