Dynamic Relationships Between Structure and Saponins Accumulation in Vegetative Organs of Alternanthera philaxeroid Criseb

The relationships between anatomical structure and the content of saponins in vegetative organs of Alternanthera philaxeroid were studied by means of histochemical localization,light microscope and quantitative analysis.The results showed that triterpenoid saponins are accumulated in the perennial roots,stems,rhizomes and leaves of A.philoxeroides,especially rich in leaves and rhizomes.The contents of triterpenoid saponins accumulated in vegetative organs are in the order of leavesrhizomesperennial rootstem under the same conditions,with leaf palisade tissue as main stored place.There were tertiary vascular bundles of concentric circular arrangement in transverse section of the perennial roots and rhizomes,which belongs to abnormal structure.Triterpenoid saponins were accumulated in secondary phloem,phelloderm,tertiary phloem and conjunctive tissue in perennial roots and rhizomes.The tertiary structure was not only the main parts in the perennial root and rhizome,but also important storage region of triterpenoid saponins.Accumulating trend of triterpenoid saponins at different collecting periods in leaves,rhizomes and perennial roots are similar,which increased with vegetative organs growing.The stem of A.philoxeroides was composed of epidermis,cortex,vascular bundle and pith cavity in transverse section,and only a few cells of cortex and primary phloem deposited triterpenoid saponins.