Micro-Root Tuber Development and Histochemistry Study of Pseudostellaria heterophylla Miq.

The feature of morphology and structure of in vitro micro-root tubes of Pseudostellaria heterophylla Miq.and their nutrition accumulation were studied using anatomy and histochemistry methods.The micro-root tubers came from inflated adventitious roots of axillary bud.The secondary growth of micro-root tubers made them enlarge.Its vascular cambium formed a large number of xylem parenchyma cells which consisted of main structure of the tuber.The micro-root tubers synthesized starches during its enlargement.Starches were the mainly storage material in the micro-root tubers,which were stored in xylem parenchyma cells.With the secondary growth of micro-root tubers,starches were firstly formed in secondary xylem parenchyma cells,and then abundant starches were also accumulated in most secondary phloem parenchyma cells.In later microroot tubers,the xylem and phloem parenchyma cells synthesized saponin materials which could be detected using a histochemical method.The development and nutrition accumulation of in vitro micro-root tubers of P.heterophylla are as same as in vivo,which will provide an assay system of P.heterophylla to investigate its tuber development and application.