Correlation Studies on the Structure and the Contents of Gypenosides in Vegetative Organs of Gynostemma pentaphyllum in Different Developmental Stages

Histochemistry technique and phytochemistry methods were applied in the studies on the relationship between the structure where ginsenosides accumulated and the contents of total gypenosides in stem and leaf of medicinal plant Gynostemma pentaphyllum in different developmental stages.The results indicated that ginsenosides appeared color reaction from purple to light red when met special chromogenic agent,and the shade of color showed a positive correlation to the contents of ginsenosides in vegetative organs.In terms of leaf,ginsenosides distributed mainly in mesophyll tissue,the contents was higher in undifferentiated mesophyll than that in mature(tissue),while the effete leaf contained no ginsenosides.As to stem,ginsenosides distributed mainly in the external phloem parenchyma cells,much less in epidermis,assimilating tissue,(collenchyma)and phelloderm,and no coloration in xylem and pith parenchyma.The younger stem had a higher content of total gypenosides than that of mature and older stem,while rhizome,the storage organ,had the highest content.Within a plant,the accumulation of total gypinosides in the leaf occupied first place,the stem came second,and the current rhizome the highest in the same developmental stage.The idea that gypenosides accumulated in leaf,translocated in stem and storaged in rhizome and the suggestion of harvest were put forward in this paper.