银州柴胡根的发育解剖学研究

本研究采用常规石蜡切片结合荧光显微镜技术对银州柴胡根的发育解剖学进行了研究。结果表明:（1）银州柴胡根顶端分生组织由原分生组织及其衍生的初生分生组织组成。原生分生组织细胞体积小、排列紧密、细胞质浓厚、细胞核大而明显，具有典型的分生组织的特点；（2）初生分生组织由根冠原、表皮原、皮层原和中柱原组成。在根发育过程中，表皮、皮层和维管柱共同组成其初生结构。银州柴胡根初生木质部为二原型或三原型，外始式；同时在根表皮细胞的径向壁观察到径向壁的细胞壁加厚；（3）在根次生生长过程中，位于初生木质部和初生韧皮部之间的原形成层恢复分裂能力产生维管形成层，维管形成层不断地向外产生次生韧皮部，向内产生次生木质部；同时位于根内皮层内方的中柱鞘细胞恢复分裂能力产生木栓形成层，木栓形成层向外形成木栓层，向内形成栓内层。在维管形成层和木栓形成层分裂的过程中，在次生韧皮部和中柱鞘组织中产生形态大小不同的分泌道，均为次生的裂生型分泌道。研究认为，银州柴胡根的结构类似于药典收录的北柴胡和红柴胡根的结构特点，但其根表皮细胞径向壁加厚、木纤维的分布、分泌道的大小和数量等有别于柴胡属其它植物，可作为柴胡属植物重要的分类鉴定依据。

Development Anatomy of Bupleurum yinchowense Roots

In this study, the developmental anatomy of the roots of Bupleurum yinchowense was studied using paraffin sectioning and fluorescence microscopy. The results show that (1) The root apical meristem of B. yinchowense is composed of promeristem and primary meristem. The promeristem are characterized by small size, closely arranged, dense cytoplasm and large nucleus, showing characteristics of typical meristem. (2) The primary meristem consists of calyptrogen, protoepidermis, ground meristem and plerome. During the development of the primary root structure, the protoepidermis forms epidermis, the ground meristem develops into cortex, and the plerome forms vascular cylinder, and the epidermis, cortex and vascular cylinder form the primary structure of the root. The primary xylem of B. yinchowense roots is diarch or infrequent triarch, and the development of which is exarch. The the root epidermal cell walls is characterized by thickening in the radial walls. (3) In the root secondary growth, the original cambium between the primary xylem and the primary phloem continue to divide and produce vascular cambium. The vascular cambium continuously produces secondary phloem outward and forms secondary xylem inward. At the same time, the pericyclic cells differentiate continuely and form the cork cambium, and the cork cambium forms the cork layer outward and the phelloderm inward. During the development process of the B. yinchowense roots, the secretory canals with different shapes and sizes are detected in the secondary phloem and pericycle tissue, both of which are secondary and schizogenous. The results showed that the structure of Bupleurum yinchowense root was similar to B. chinense and B. scorzonerifolium, but the thickening of the radial walls of the root epidermal cells, the distribution of wood fibers, the size and number of secretory canals and so on were different from other plants in Bupleurum, which could be used as an important basis for the classification and identification.