Ceratopteris pteridoides (Hook.) Hieron.的根的內外部構造

Macro- and Microscopic Structure of the Root of Ceratopteris pteridoides (Hook.) Hieron

The structure of the root of C. pteridoides is almost identical with that of C. tholictroides, except in the former species the root shows somewhat less orderliness regarding the arrangement of lateral roots. The occurrence of lateral roots is related to the leaf rather than to the root apical cell. Since the new immediate lateral derivative of the apical cell is always produced beside the oldest cell of the three surrounding cells cut off from the three side faces of the apical cell, it is suggested that the regular formation of the new cells in cyclic order from the apical cell is dependent on the simultaneous presence of its surrounding cells of different ages. Since the walls of the rootcap are always thicker than those of the meristematic cells in the root tip, it is thought that this relative inflexible rootcap may act as a mould, contributing to nance of a definite form of the root tip by casting a mass of flexible cells of the the mainteapical meristem in it. The formation of rootcap is found essential in the construction of root proper in this fern.