乌拉尔甘草根与根状茎发育解剖学研究

应用常规石蜡切片方法,对乌拉尔甘草根和根状茎的结构及其发育进程进行研究.结果显示:(1)乌拉尔甘草根的发育包括原分生组织、初生分生组织、初生生长和次生生长4个发育阶段.原分生组织由3层原始细胞组成,具有典型分生组织细胞的特征;初生分生组织由根冠原、表皮原、皮层原和中柱原组成;初生结构包括表皮、皮层和中柱,初生木质部为4原型,偶见3原型,内皮层细胞具凯氏带;次生生长依靠维管形成层和木栓形成层活动完成,维管形成层源于初生木质部和初生韧皮部之间的薄壁细胞,而木栓形成层由中柱鞘细胞脱分化产生;次生结构由次生维管组织和周皮共同组成,根中央不具髓.(2)根状茎发育过程与地上茎类似,包括原分生组织、初生分生组织、初生生长和次生生长4个发育阶段.原生分生组织由原套和原体组成,其衍生细胞分化成由原表皮、基本分生组织和原形成层组成的初生分生组织;初生结构包括表皮、皮层、外韧维管束、髓和髓射线,维管束呈环形排列;位于维管束中的原形成层细胞恢复活动产生次生木质部和次生韧皮部,束间形成层产生射线细胞;靠近维管束内侧的皮层薄壁组织细胞脱分化产生木栓形成层,以后形成周皮.周皮、次生维管束、射线和髓共同构成根状茎的次生结构.

Anatomical Study of Glycyrrhiza uralensis Roots and Rhizomes

In order to discuss the anatomical characteristics and development process,taproots and rhizomes of Glycyrrhiza uralensis in different growth ages were investigated by means of conventional anatomical methods.The results showed that development of Glycyrrhiza uralensis taproot could be divided into four stages that including promeristem,primary meristem,primary and secondary growth.The promeristem contains three groups of initial cells with characteristic of meristematic cell.Primary meristem is composed of calyptrogens,primordial epidermises,periblems and pleromes.The epidermises,cortex and stele comprised primary structure,in which the primary xylem was tetrarch and the caspary strip occurred on the endodermis cells wall.The secondary growth originated from the successive activity of vascular cambium and cork cambium to form secondary vascular tissues and periderm.Development characteristics of the rhizome also could be divided into four stages as above,but promeristem was composed of two layers of tunica cells and a group of corpus cells.With the development of promeristem,the primary meristem including protoderm,procambium and ground meristem was formed at the apex of the rhizome.Furthermore,the primary meristem differentiated into primary structure consisting of epidermis,vascular bundle,cortex and pith.In the secondary growth,the fascicular cambium differentiated to produce secondary xylem and phloem,while the interfascicular cambium to form paraenchyma of the ray.Besides of the fascicular and interfascicular cambium activity,cork cambium originated from cortex cell near the endodermis differentiated to form periderm.So the secondary structure of the rhizome was constituted by periderm,secondary vascular tissues.