Research On Physiological And Biochemical Indices Of Drought Resistance Of Four Species In Atriplex

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. canescensï¹¥A.obovata> A.lentiformis. The relative water content results showed that A.gardneri>A.lentiformisï¹¥A. obovata>A. canescens. The water potential results indicated that A. lentiformis>A. gardneri>A. canescensï¹¥A. obovata. The ratio of bound water and free water results showed that A.gardneri>A.lentiformisï¹¥A. obovata>A. canescens. The water holding capacity results indicated that A.gardneriï¹¥A.canescensï¹¥A.obovataï¹¥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.lentiformisï¹¥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...