The Research Of Stress-Resistance Physiological Characteristic Of Three Woody Saltbushes

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 Provinces in China, where had the similar features to its original place. It had a great potential in development according to the area experiment. Atriplex Canescens, Atriplex Gardneri and Atriplex Tridentate which were introduced from American and Hippophae rhamnoides, Ulmus pumila were seclected as the material and planted in Forestry Garden of Northwest A&F University in this study to research the effect of water stress, salt stress on their physiological characteristics in order to offer some certain foundations for selecting the fine varieties for the northwestern area in China.This study was divided into the drought-resistance and salt-resistance of atriplex plants. The results showed that:1. The ability of keeping water for five plants in water stress condition was: A. Tridentate>A. Gardneri>A. Canescens>H. rhamnoides>U. pumila. The effects of water stress on atriplex plants potential was less than H. rhamnoides and U. pumila.2. The cell membrane of three atriples plants was stable basically and the structure and function of membrane also had a little damage in water stress condition. But the MDA and membrane permeability of H. rhamnoides were increased very much. The MDA of U. pumila was stable in middle water stress while quite increased in high water stress. This indicated that the cell membrane of H. rhamnoides and U. pumila was damaged badly. The drought-resistance of these two plants was less than others. The cell membrane of three atriples plants was stable and had a little harm in salt stress condition. The MDA and membrane permeability of H. rhamnoides and U. pumila was increased in Na2SO4,NaCl stress. The U. pumila was dead in the highest NaCl stress. This indicated that its ability of salt-resistance was weak.3.The water stress had a little effects on Chl content of three atriples plants and the Chl content of other two plants was decreased. The effect of water stress on Pn of five plants in was: H. rhamnoides> A. Tridentate> U. pumila>A. Gardneri>A. Canescens. But the effects on growth was: H.rhamnoides>U.pumila>A.Gardneri> A.Tridentate>A. Canescens.The effects of NaCl stress on Chl was: U. pumila> H. rhamnoides> A. Canescens> A. Tridentate>A. Gardneri. The effects of Na2SO4 stress on U. pumila was higher than others. And the effect of NaCl stress on Pn was: U. pumila>H. rhamnoides>A. Canescens>A. Tridentate>A. Gardneri. While in Na2SO4 stress the Pn of five plants was: U. pumila>H. rhamnoides> A. Gardneri > A. Tridentate >A. Canescens.4. The proline content of five plants was increased under water and salt stress. But they had big variety on extent. It indicated that proline accumulation had no relationship with drought-resistance and salt-resistance. But it had an important role in physiological adjustment under water and salt stress condition.5. Through the analysis of subordinate function values, A. Tridentate had the strongest drought-resistance. The next was A. Canescens. The NaCl-resistance of three atriplex plants was increased following with the increasing of salt stress especially the A. Gardneri had the strong salt-resistance ability. The Na2SO4-resistance of three atriplex plants was increased following with the increasing of salt stress. The salt-resistance of A. Gardneri and A. Tridentate was still increasing in the highest salt stress indicated they had strong Na2SO4-resistance ability.