关键词: 狭叶柴胡, 根, 发育解剖

Abstract: The development of Bupleurum scorzonerifolium Willd. root was studied with paraffin sectioning and the structure of the annual and the perennial taproots were compared and analyzed. It was shown that the development of B.scorzonerifolium root could be divided into four stages: promeristem, primary meristem, primary structure and secondary stages of growth.The promeristems consist of three groups of initial cells,which have the cytological characteristics of typical meristem cells;the primary meristems are composed of calyptrogens, primordial epidermises, periblems and pleromes. The primary structures include epidermis, cortex and stele. The primary xylem is diarch, triarch is few. The secondary structures include periderm, pericyclic parenchymna cycle and secondary vascular tissue, from the outside to the inside. The secondary growth mainly relies on the activities of vascular cambium and cork cambium; the cork cambium formed from pericyclic cells that resumed their dividing capabilities.The perennial root have the similar structure to the annual one, but there were some differences in the quantity of cells and structure of each parts. Secretory canals of annual root are only distributed in the pericyclic parenchymna, but they are distributed both in the pericyclic parenchymna and the secondary phloem in perennial roots.

Key words: Bupleurum scorzonerifolium Willd., root, developmental anatomy