荒漠植物白刺对风沙流和干旱复合胁迫的协调适应机制

Wind-blown sand and drought are the key factors affecting stability of desert ecosystem. For discussing the effects of combined stress of wind-blown sand and drought on typical desert vegetation in Minqin desert, we take Nitraria tangutorum Bobr. as the research object, which is the important constructive species in the transition zone between Minqin desert and oasis. The project intends to analyze response regularities about water physiological characteristics, photosynthesis and morphological characteristics of this plant induced by combined stress of wind-blown sand and drought with the method of located field observation and stress simulation. On basis of the analysis results, we will explore the physiological ecological response mechanism of this plant to the combined stress. The adaptive strategy of this plant to the combined stress will be expounded according to internal photosynthetic apparatus and external morphological characteristics. The study results will become the theoretical basis applied to evaluate the effect of the combined stress of wind-blown sand and drought to degradation of Nitraria tangutorum. It will lay the foundation of making measures for restoring and conserving desert ecosystem.

风沙流和干旱是影响荒漠生态系统稳定的关键因素。为探讨风沙流和干旱复合胁迫对荒漠植被所造成的影响，本项目拟采用野外定位观测和胁迫模拟实验相结合的方法，以民勤荒漠绿洲过渡带典型的建群植物种白刺为研究对象，对风沙流和干旱复合胁迫条件下白刺幼苗水分生理、光合作用和形态特征的响应规律进行分析。深入探讨白刺在风沙流和干旱复合胁迫条件下的生理生态响应机理，从内在光合机构和外在形态特征两个层面阐明白刺对风沙流和干旱复合胁迫的适应策略。研究结果可为科学地评价风沙流和干旱复合胁迫对民勤荒漠区白刺灌丛退化的影响提供理论依据，同时也可为荒漠生态系统恢复和保育措施的制定奠定基础。

民勤荒漠区自然环境非常恶劣，干旱和风沙流经常发生，对植物生长发育具有显著影响。荒漠植物能够在干旱和风沙流并存的情况下生存下来，必然有其独特的适应机制。本项目以民勤荒漠区分布面积较广的植物白刺为研究对象，采用野外观测和控制实验相结合的方法，通过分析干旱和风沙流复合胁迫对白刺水分生理、光合作用、叶绿素荧光参数以及抗氧化酶活性的影响，从植物生理水平上揭示白刺对干旱和风沙流复合胁迫的协调适应机制。结果表明，白刺对干旱和风沙流复合胁迫耐受性较强的特征表现为：叶片相对含水量较低，叶片保水力、净光合速率、水分利用效率、光化学效率以及用于光化学反应的激发能分配比例均较高。该研究成果在揭示荒漠植物逆境适应机制研究方面具有重要的参考价值，同时，对于干旱荒漠区植被修复也具有一定的指导作用。