Endogenous Gibberellins from Three East Asian Stenophora Species of the Genus Dioscorea (Yams)

Exogenous gibberellin A (GA; 30 μm) promoted shoot elongation of germinated seeds of Dioscorea nipponica, an East Asian species of a taxonomic section Stenophora of the genus Dioscorea (yams). Endogenous gibberellins (GAs) were analyzed by combined gas chromatography-mass spectrometry (GC-MS) from growing shoots of three East Asian Stenophora species. Gibberellin A, GA, GA , GA and GA were identified by Kovats retention indices and by full spectra of GC-MS from D. quinqueloba. Gibberellin A, GA and GA were also identified from D. nipponica and D. septemloba. These results suggest that two separate biosynthetic pathways of GAs, early 13-hydroxylation and non-13-hydroxylation pathways are functioning in the growth of shoots of these thee species.