维管植物导管元素分化与细胞程序性死亡

通过遗传控制的细胞死亡是植物正常生长和发育的重要过程，是近年来国内外的研究热点之一。维管植物的导管和筛管由死亡的管导分子组成，本文着重讨论了维管植物的导分子形成过程中的细胞程序性死亡（ｐｒｏｇｒａｍｍｅｄ ｃｅｌｌｄｅａｔｈＰＣＤ）的形态和化特性以及参与找在因，并介绍了植物生长发育过程中ＰＣＤ存在的时空广泛性。虽然植物发育生殖过程中的ＰＣＤ与动物细胞通过遗控制的细胞死亡是植物正常生长和发育的重要过程，是近年来国内外的研究热点之一，维管植物的导管和筛管由天文馆的导管分子组成。本文着重讨论了维管植物的导管分子形成过程中的细程序性死亡（programmed cell death PCD)的形态和生化特征以及参与的基因，并介绍了植物生长发育过程中ＰＣＤ存在的时空广泛性。虽然植物发育和生殖过程中的ＰＣＤ与动物细胞凋亡存在许多相似的形太必生化特征，但细胞通过自溶或自自我吞噬来死亡，而并不形成动物细胞凋亡中典型的凋亡小体。说明这些ＰＣＤ类型本质上凋亡型ＰＣＤ。导管分子的死亡是一种典型的植物ＰＣＤ。近年来体外系统研究表明，导管元素分析中的细胞死亡程序与动物细胞凋亡不同。

PROGRAMMED CELL DEATH DURING TRACHEARY ELEMENT DIFFERENTIATION IN VASCULAR PLANTS

Genetically cell death is part of a normal plant's healthy course of growth and development and the investigations on it are blossoming in the recent years. This review describes in detail programmed cell death (PCD) involved in xylem differentiation, including the morphological and biochemical features and genes involved, and discusses the temporal and spatial ubiquity of PCD during plant growth and development as well. Although certain hallmarks of apoptosis of animal cells are detectable during some plant developmental PCD processes, the participation of autolytic and perhaps autophagic mechanisms of cell killing support the conclusion that nonapoptotic PCD pathways are essential during normal plant growth and development. During plant cell suicide, especially in TE differentiation, autolysis and autophagy appear to govern the elimination of cells instead of formation of apoptotic bodies, which is a typical morphological characteristics of animal apoptosis. Vascular plants have vessels and tracheids composed of dead TEs. Death of TEs is a typical example of PCD in plants. Recent studies on TE differentiation, in particular with an in vitro differentiation system, have revealed a unique cell death process which differs from apoptosis.