植物耐旱性及其机理

本文综合评述了植物的各种耐旱机理。依据植物对干旱胁迫的反应行为,把植物的耐旱机理分为3个基本类型:(1)逃避干旱;(2)高水势延迟脱水耐旱;(3)低水势忍耐脱水耐旱。逃避干旱的植物(如沙漠短生植物)具有在严重的干旱胁迫发生之前就完成其生命周期的能力,但它们的特点本文未加以讨论。而着重讨论了忍耐干旱的植物的耐旱特点。高水势延迟脱水的植物是以保持水分吸收和减少水分丧失为其主要的耐旱特征。而低水势忍耐脱水的植物则是以保持膨压和原生质忍耐脱水为其主要特征。

Mechanisms of Drought Tolerance in Plants

The various mechanisms of drought tolerance in plants has been reviewed in this paper. According to ways of responsing on drought stress, three primary types of drought tolerance in plants have been identified: (1) drought escape; (2) drought tolerance of dehydration postonement with high tissue water potential; (3) drought tolerance of dehydration tolerance with low tissue water potential. Drought escaping plants, known as desert ephemerals, are of the ability of completing their life cycle before a serious water stress develops, but their characteristics of drought escape have not been discussed in this paper. The characteristics of drought tolerating plants have been concentrated on discussing in this paper. The main characteristics of drought tolerance in plants that have the ability of dehydration postonement with high water potential are maintenance of water uptaker and reduction of water loss. The main characteristics of drought tolerance in plants which are of the ability of dehydration tolerance with low water potential are maintenance of turgor and protoplasmic desiccation tolerance.