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 (GA^sub 53^,GA^sub 44^, GA^sub 19^, GA^sub 20^ and GA^sub 1^), and sixare members of the non-13-hydroxylation pathway (GA^sub 12^,GA^sub 15^, GA^sub 24^, GA^sub 9^, GA^sub 36^ andGA^sub 4^). Of these eleven, GA^sub 44^, GA^sub 15^ andGA^sub 1^ 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 activeGA^sub 4^ content for all harvest dates was greater than that ofGA^sub 1^ in the leaves and tubers during tuber development. It issuggested that the higher level of GA^sub 4^ in the leaves and tubers maybe closely related to tuber enlargement.[PUBLICATION ABSTRACT]