Using an improved purification and derivatization procedure, the endogenous gibberellin-O-glucosides in mature runner beans (Phaseolus coccineus) were analysed by combined gas chromatography-mass spectrometry. In addition to the previously characterized GA1-3-O-glucoside and GA8-2-O-glucoside, from runner beans, the following GA-O-glucosides were identified as endogenously occurring compounds by comparison of their full scan mass spectra and Kovats retention indices with those of standards: GA1-13-O-glucoside, 3-epiGA1-3-O-glucoside, GA5-13-O-glucoside and GA29-2-O-glucoside. The first three are reported in higher plants for the first time. The physiological relevance of the detected GA-O-glucosides is discussed.

Data on the occurrence of free and conjugated gibberellins in different tribes of Gramineae are compiled and discussed with regard to their biosynthetic pathways. From the gibberellins detected so far the functioning of both the early 13-hydroxylation and the non-3,13-hydroxylation pathway of GA biosynthesis in gramineous plants can be deduced and the discovery of further gibberellin conjugates may be expected.