Quantification of endogenous gibberellins in leaves and tubers of Chinese yam, Dioscorea opposita Thunb. cv. tsukune during tuber enlargement

Elevengibberellins (GAs) were identified and quantified in extracts of leaves andtubers of the Chinese yam, Dioscorea opposita Thunb. cv.Tsukune by GC-MS-SIM and Kovats retention indices. Five of these gibberellinsare members of the early-13-hydroxylation pathway (GA53,GA44, GA19, GA20 and GA1), and sixare members of the non-13-hydroxylation pathway (GA12,GA15, GA24, GA9, GA36 andGA4). Of these eleven, GA44, GA15 andGA1 were detected for the first time in Dioscoreaopposita leaf tissues. The major biosynthetic GA pathway in leavesofChinese yam was non C-13 hydroxylation (NCH). In addition, the activeGA4 content for all harvest dates was greater than that ofGA1 in the leaves and tubers during tuber development. It issuggested that the higher level of GA4 in the leaves and tubers maybe closely related to tuber enlargement.