Abstract

The aims of this study were first to investigate the possible gibberellins biosynthetic pathway operated in corm of kohlrabi at early corm formation, enlargement and harvest. Ten gibberellins (GAs) were identified and quantified in extracts of corm of the different skin colour of kohlrabi, Brassica oleracea var. gongylodes L. by GC-MS-SIM and Kovats retention indices. Five of these gibberellins were members of the early-C13-hydroxylation pathway (GA53, GA19, GA20, GA8 and GA1), and five were members of the non-C13 hydroxylation pathway (GA12, GA24, GA9, GA7 and GA4). Of these 10 gibberellins, GA7 and GA24 were commonly the most abundant in corm of two different skin colours of kohlrabi, whereas GA12 was lowest during growth. Bioactive endogenous GA4 was dominant and always higher than that of GA1 in corm of kohlrabi during growth. In consequently, major gibberellins biosynthetic pathway operated in corm of kohlrabi was an early C-13 hydroxylation route.