绞股蓝龙须茶的人参皂甙组织定位及皂甙含量的季节变化

应用组织化学定位技术及植物化学方法，研究了人参皂甙在商品绞股蓝龙须茶中的组织分布状态及绞股蓝总皂甙在不同季节中的含量变化。结果表明，绞股蓝内的人参皂甙遇特定的显色剂出现深浅不同的红色，色度与人参皂甙含量呈正相关。绞股蓝叶内的人参皂甙主要分布在叶肉组织，茎内的人参皂甙主要分布于维管束的韧皮部薄壁细胞中，同化组织、厚角组织和表皮也有少量分布．木质部和髓薄壁组织中无皂甙分布。在4月至11月的龙须茶采收期中，总皂甙含量呈逐渐上升的势态，4月最低．9月最高，含量变化与月总降雨量呈显著的正相关。研究认为在8月后湿润凉爽气候条件下采摘绞股蓝芽尖加工而成的龙须茶品质最好。

Histochemical Localization and Seasonal Change of Ginsenoside in Herb Tea (Gynostemma pentaphyllum)

Histochemical technique and phytochemical methods were applied in the studies on the distribution and accumulation of ginsenosides in the tissues of Gynostemma pentaphyllum,a medical herb, whose buds, young stems and leaves were processed as Longxu tea. Seasonal changes of total gypenosides in the health tea was also detected. The results indicated that ginsenosides showed color reaction from purple to light red if met special chromogenic agents, and the shade of color showed a positive correlation to the contents of ginsenosides in vegetative organs. Ginsenosides distributed mainly in mesophyll tissue in leaf, and external phloem parenchyma cells in stem, much less in assimilating tissue, collenchyma and epidermis in stem, no accumulation in xylem and pith parenchyma. The contents of total gypenosides in Longxu tea increased in the harvest period from the lowest in Apr. to the highest in Sept..There was a significant positive correlation between the contents of gypenosides and the monthly total precipitation. It is suggested that the quality tea should be harvested and process after Aug. when the climate is wet and cool.