位置效应对拟南芥根冠柱细胞的影响

Positional Effect on Columella Cells of Arabidopsis Primary Roots

摘要: 柱细胞是根冠中两种细胞类型之一，位于根尖的最前端。在模式植物拟南芥中，柱细胞的产生与分化过程高度同步，形成规则的层状结构。柱细胞之间是否存在差异目前并不清楚。本研究通过对野生型和WOX5过表达幼苗的主根中的柱细胞的分裂模式和排列方式的分析，发现不同位置的柱细胞在分裂模式，细胞形态和细胞排列方式等方面呈现出明显差异。在野生型幼苗中，外围区的柱细胞与中央区的柱细胞相比更容易出现不规则细胞分裂与不规则细胞排列。在WOX5过表达的幼苗中，中央区的柱细胞的分裂模式，细胞形态和细胞排列方式与正常柱干细胞接近，而外围区的柱细胞与侧根冠细胞更为接近。本研究的结果为进一步了解柱细胞的发育及其调控机理提供了一个新实验系统和一条新的研究思路。

Abstract: Columella cells are one of the two cell types in the root cap of higher plants and are positioned at the forefront of a root tip. In the model plant Arabidopsis, the formation and differentiation of columella cells are highly synchronized, resulting in a typical layered structure. It is currently not clear whether there are any differences between columella cells. In this study, we analysed the division pattern and cellular arrangement of the columella cells in the main root of both wild-type and WOX5 over-expressing seedlings and found differences in the division pattern, cell morphology and cellular arrangement between columella cells in different positions. In wild-type seedlings, the columella cells in the peripheral zone were more likely to undergo irregular cell division or to have abnormal arrangement than those in the central zone. In WOX5 overexpressing seedlings, the division pattern, morphology and arrangement of columella cells in the central zone were similar to those in the normal columella stem cells, while columella cells in peripheral zone were more similar to those of the lateral root cap cells in the above-mentioned characteristics. The results of this study form a basis for a new experimental system and offer a new research strategy for studying the development and regulatory mechanisms of columella cells.