【作者】 李健；

【导师】 蒋志荣； 王继和；

【作者基本信息】 甘肃农业大学 ， 森林经理， 2006， 硕士

【摘要】 滨藜属植物( Atriplex )是全世界干旱、半干旱地区的典型植物,具有适应性强、耐旱、耐盐碱的特点。既是垦荒、退化牧场改良的荒漠地带植被,亦是优良的饲料植物,已成为其原产地美国西部干旱地区重要的饲料灌木之一。20世纪90年代后期,由于其产地的生境与我国西北干旱区有一定的相似性,青海、新疆、宁夏等地先后引进滨藜,区域性栽培试验表明,具有很大的发展潜力。本文选取了引种于美国,栽培于民勤沙生植物园的四种滨藜: A.canescens; A.obovata; A.gardneri;A.lentiformis作为实验材料,通过控制水分,造成水分胁迫的手段,对其抗旱性生理生化指标进行了研究,希望为筛选适合西北荒漠地区生长的滨藜品种提供一定的理论依据。实验得出以下结论:经过隶属函数对水分指标的分析,四种滨藜分别有着不同的表现:在组织含水量指标上,A. gardneri>A. canescens﹥A.obovata> A.lentiformis;在相对含水量指标上,A.gardneri>A.lentiformis﹥A. obovata>A. canescens;在水势指标上,A. lentiformis>A. gardneri>A. canescens﹥A. obovata;在束/自比值指标上,A.gardneri>A.lentiformis﹥A. obovata>A. canescens ; ,持水力顺序依次为A.gardneri﹥A.canescens﹥A.obovata﹥A.lentiformis。研究发现四种滨藜的净光合速率Pn,日变化总体上呈“中午降低”型日变化,即有“午休”现象,这有利于降低蒸腾量,提高水分利用率,同时也表明了对民勤地区环境的一种适应。A.canescens和A.gardneri的净光合速率日进程呈单峰曲线, A.obovata和A.lentiformis的Pn日进程呈近似的双峰曲线。总体上讲,A.gardneri>A.lentiformis﹥A. obovata>A. canescens。随着胁迫的加剧,A.lentiformis超氧自由基产生量明显上升,而A.gardneri的超氧自由基产生量则有明显的下降,A.canescens和A.obovata的变化幅度很小, A.lentiformis和A.gardneri与其他两种滨藜差异性显著。胁迫10天到20天,四种滨藜的SOD、CAT、POD活性绝大多数都处在上升趋势,这些结果表明了在胁迫前期四种滨藜体内保护酶系统能够有效运行,避免活性氧的大量积累,在胁迫20天进行到30天时,四个种间3项生理指标发生了显著变化,A.canescens的CAT、POD活性出现下降趋势,A.lentiformis的SOD和CAT、POD活性均下降;说明这两种滨藜受到干旱胁迫影响程度较大;而A.gardneri更多还原

【Abstract】 Atriplex was one of the typical plants which were tolerated to water stress all over the world. It had strong adaptabilities to water stress and salt stress. It was used not only as vegetation in wastelands and desolations which used to be meadows, but also as feeding stuff. Moreover, it was one of the main fodder crops whose original place was western dry area in America. In the late 1990s, Atriplex was introduced to Qinghai ,Xinjiang and Ningxia Province in China, which places had the similar features to its original place. It had a great potential in development according to the area experiment. A.canescens; A.obovata; A.gardneri;A.lentiformis were selected as the material in this study to research the effect of water stress on their physiological characteristics in order to offer some certain foundations for selecting the fine varieties for the northwestern area in China.The results showed that the four kinds of Atriplex had different performances according to the analysis of subordinate function. The results of the absolute water content of four kinds of Atriplex showed that A. gardneri>A. canescens﹥A.obovata> A.lentiformis. The relative water content results showed that A.gardneri>A.lentiformis﹥A. obovata>A. canescens. The water potential results indicated that A. lentiformis>A. gardneri>A. canescens﹥A. obovata. The ratio of bound water and free water results showed that A.gardneri>A.lentiformis﹥A. obovata>A. canescens. The water holding capacity results indicated that A.gardneri﹥A.canescens﹥A.obovata﹥A.lentiformis. The results of this research showed that the net photosynthesis rate of four kinds of Atriplex decreased at noon, showing the presence of midday depression of photosynthesis. It was affected by high temperature and strong light intensity, which was good for decreasing transpirationary rate and increasing the water use efficiency. The diurnal trend of the net photosynthesis rate in A.canescens and A.gardneri were single-climax curves, while in A.obovata and A.lentiformis were double-climax curves. In all, the adaptabilities to water stress were A.gardneri>A.lentiformis﹥A. obovata>A. canescens.The content of superoxide anion radical (O2-) of A.lentiformis increased but A.gardneri decreased and there were little changes in A.canescens and A.obovata更多还原