芡实根系的发育与结构研究

STUDIES ON THE DEVELOPMENT AND STRUCTURE OF THE ROOT SYSTEM IN EURYALE FEROX SALISB

芡实的根系主要由不定根组成。不定根起源于叶柄基部膨大处外侧的薄壁细胞组织中。根的表皮、皮层、维管柱和根冠起源于根顶端的同一原始细胞层。不定根无根毛,六原型。次生根由邻接原生木质部的辐射角尖端的中柱鞘细胞和内皮层细胞共同分裂分化形成。

The present paper deals only with a study of the development and structure of root system in Euryale ferox Salisb, The adventitious roots, arising in clusters at the basal portion of the leaf stalks form the main root system of the plant. Adventitious roots are initiated from several contiguous parenchyma cells with dense cytoplasm and large nuclei, and divide periclinally and anticlinally for many times. The accumulating cells form the root primordia at last. As in most of the water plants, these roots possess no root hairs and the rootcap protects and encloses the root apical meristem in the form of a pocket. Air passages and diaphragms are formed in the cortex. The differentiation and maturation of the vascular tissue in the cylinder are similar to that of the other higher plants.The pericycle consists of large cells which usually differentiates with the neighbouring endodermis cells to form the secondary root. Thus, the secondary roots are originated from two different kinds of tissues, namely the endodermis and the pericycle. Further differentiation and maturation are similar to the development of adventitious roots.