空心莲子草营养器官结构与三萜皂苷动态积累的关系

采用组织化学定位、显微制片技术和三萜皂苷定量分析方法对空心莲子草营养器官结构与三萜皂苷类物质积累关系进行了研究。结果表明：空心莲子草宿根、根状茎、茎和叶中均有三萜皂苷物质的积累，叶和根状茎内含量十分丰富。在相同采收期内含量依次为：叶＞根状茎＞根＞茎，叶中主要积累于栅栏组织细胞内。空心莲子草的根和根状茎横切面均属于异常结构，具有成同心环状排列的三生维管束。在宿根和根状茎的次生韧皮部、栓内层、三生韧皮部和结合组织内均有三萜皂苷的分布，三生结构在宿根和根状茎中占有主要地位，是三萜皂苷积累的主要场所。在不同采收期内叶、根状茎和根中三萜皂苷的积累趋势基本一致，均随生长期的增加而递增。空心莲子草茎的横切面由表皮、皮层、维管束和髓腔组成，仅部分皮层细胞和初生韧皮部内有三萜皂苷分布。

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 leaves>rhizomes>perennial root>stem 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.