黄芩根的解剖学研究

用常规石蜡切片方法对黄芩(Scutellaria baicalensis Georgi)一、二年生主根的发育及结构进行解剖学研究.结果表明,黄芩根的发育可分为原分生组织、初生分生组织、初生结构和次生生长等4个阶段.原分生组织由3 群原始细胞组成,其细胞具有典型分生组织的细胞学特征;初生分生组织包括根冠原、表皮原、皮层原和中柱原,其中根冠原和表皮原具有相同的起源.初生结构由表皮、皮层和中柱组成.初生木质部为二原型.次生生长主要是由维管形成层和木栓形成层的活动完成,木栓形成层起源于中柱鞘细胞.二年生黄芩主根的主要结构与一年生的基本相同,其不同之处为:二年生主根的周皮增厚,次生木质部中木纤维成群分布,出现木间木栓;维管射线为多列且明显;在近周皮的韧皮部内出现包围石细胞的木栓环组织.

Anatomical Studies on the Root of Scutellaria baicalensis Georgi

The development and the structure of the one-year-old and two-year-old root of Scutellaria baicalensis Georgi were studied by paraffin section. The development of root could be divided into four stages, promeristem, primary meristem, primary structure and secondary growth stage. The promeristem is consisted of three groups of initial cells, which have typical cytological characteristics of meristem cells. The primary meristem is composed of calyptrogens, primordial epidermises,periblems and pleromes. Both the calyptrogens and the primordial epidermises initiate from the same layer of initial cells. The primary structure consistes of epidermis, cortex and stele. The primary xylem is diarch. The secondary growth mainly depend on the activities of vascular cambium and cork cambium ; the cork cambium originates from pericyclic cells. The structures of the two-year-old tap roots are similar to that of the one-year-old ones, while the periderm thickness is increased. In the secondary xylems of the two-year-old roots, the woody fibers are distributed in groups and the interxylary phellem appears. The vascular rays are muhiseriate. Phellem cells surround a sclereid form the phellem cycle in the phloem nearby the periderm.