买麻藤根的异常次生生长

买麻藤(Cnetum montanum)根的异常次生生长与茎的异常次生生长相似,位于维管束外围的薄壁组织细胞可以形成维管束,以这种方式使根加粗。并且在生长过程中以同样的方式,在维管束的外围不断形成新的维管束。这些新的维管束成环状排列,因此,在老根中呈多圈的维管束。与茎唯一不同的是根的异常次生生长为不均等的,在两个宽大的射线区外侧,没有异常的维管束形成,因此,根主要向着与两条宽大射线相垂直的方向扩展,故外形呈扁圆形。

THE ANOMALOUS SECONDARY GROWTH OF ROOTS IN GNETUM MONTANUM

The anomalous secondary growth of roots is similar to the stem in Gnetum montanum. It grows thicker through the unceasing formation of new vascular bundles by the pareuchyma cells located around the periphery vascular bundles. In the process of growth, these new vascular bundles also form vascular cells arranged in circles around the original periphery vascular bundles. The only difference between the anomalous secondary growth in shoots and roots is that in roots it is uneven, and there are no extraordinary new anomalous vascular bundles found toward outside the broad medullary rays of the primary xylem. Therefore, the roots mainly extend in the direction in which they are perpendicular to the two broad rays, and are oblate in appearance.