银杏黄酮苷和萜类内酯含量的季节变化

以银杏（Ginkgo biloba L.)2年生实生苗和大树为试材，分析根、茎和叶中银杏黄酮苷及萜类内酯含量的季节变化规律。银杏叶中萜类内酯含量从春季起逐渐增加，至夏末秋初达最高值，随后逐渐减少；根和茎中萜类内酯含量的季节变化与叶中相类似，但在冬季休眠期维持较高含量，进入春季伴随叶的萌发生长降低到全年的最低点。银杏茎中萜类内酯含量最低，相当于叶含量的1／3和根含量的1／2。叶中白果内酯含量在总萜类内酯中所占比例较高，而在根和茎中所占比例则较低。随着树龄增加，银杏叶萜类内酯含量下降，这可能与萜类内酯合成能力下降有关。银杏黄酮苷含量在春季幼叶中最高，夏季和秋季相对较低且变化不明显；长枝叶中槲皮素较多，而短枝叶中山柰黄素较多。对不同季节和不同部位的不同成分含量的相关机理进行了讨论。

Seasonal changes of flavonol glycosides and terpene lactone contents of Ginkgo biloba

Flavonol glycosides and terpene lactone contents in leaves, stem and root of Ginkgo biloba L. 2\|yr\|old seedling as well as adult tree were determined in relation to the seasonal changes. Terpene lactone content of leaves increased gradually in spring with a maximum in late summer and early fall, thereafter decreased; terpene lactone of root and stem appeared similarity changes as leaves but maintained high content in dormancy stage in winter, then declined to the lowest when sprout in spring. Terpene lactone content of stem were the lowest, corresponding to 1/3 of leaves and 1/2 of root while bilobalide in leaves had a high ratio of total terpene lactone. Terpene lactone content decreased with tree age increment, which may be related to its biosynthetic activity decreasing. Flavonol glycosides content appeared higher in young leaves in spring, quercetin was major aglycone in leaves of long shoot, and kaempferol in leaves of short shoot. The relative mechanisms of diffenent components in different seasons and plant parts were discussed briefly.