Effects Of Drought Stress On Growth And Water Physiology Of Six Desert Shrubs

Through potted cultivate we studied six shrubs'biomass, water use efficiency,water physical characters and PV parameters. And we hoped to provide a theoretical basis for Mu Us Sandland of vegetation restoration and the selection of species. The six shrubs are: Caragana korshinskii, Atraphaxis bracteata,Hedysarum mongolicum,Hedysaru-m scoparium, Buddleja alternifolia, and Atriplex canescens. And the results were as follows:1)Under moderate drought stress,six shrubs grow well, biomass fresh weight difference was not significant. So they can be well adapting to moderate drought stress. Under severe drought stress,Atyiplex canescens had the largest biomass and also had the largest water transpiration. It meant that although severe drought stress had an impact on physical activity, it is still able to successfully complete the synthesis of assimilation and had adaptation to the severe drought stress. Buddleja alternifolia, under severe drought stress had low water use efficiency, the biomass sharp declined and transpiration also reduced dramatically. The results showed that the Buddleja alternifolia can not adapt to severe drought stress. Atraphaxis bracteata and Caragana korshinskii had similar performance, while Caragana korshinskii had a higher water use efficiency than Atraphaxis bracteata, Hedysarum mongolicum and Hedysarum scoparium can adapt to drought stess. They can respond to water stress quickly, increase water use efficiency to improve the biomass.2)We can conclude from the analysis of the PV parameters and water parameters by subordinate function, In moderate drought stress, The order of drought-resistant ability is Caragana korshinskii > Atraphaxis bracteata>Atyiplex canescen>,Hedysarum mongolicum > Hedysarum scoparium.> Buddleja alternifolia. But in severe drought stress, The order is Atraphaxis bracteata>Caragana korshinskii >Atyiplex canescen>Hedysarum mongolicum > Hedysarum scoparium.> Buddleja alternifolia.3)Plants can against drought through a variety of ways working together, in different life periods use different ways, Atriplexcanescens adapt to the drought stress by high-water potential of delayed dehydration, while low water potential dehydration; Hedysarum mongolicum, Hedysarum scoparium, Caragana korshinskii had a low transpiration, high water use efficiency and low water potential of the early morning, belong to a high-water potential delay of dehydration and drought-resistant plants; Buddleja alternifolia in moderate stress grass grow well, however, the severe drought stress seriously inhibit growth, electrical conductivity increased dramatically, synthesis of assimilation reduced sharply, obviously not adapt to the severe drought stress.