Ecophysiological Responses Of Robinia Pseudoacacia L. And Amorpha Fruticosa L. Seedlings To Different Salt Regimes

Human activities exacerbated the change of the global ecological environment. Due to global climate change, population growth, exacerbated by the impact of industrial pollution, the development of irrigated agriculture and the improper use of fertilizers and other factors, soil salinization is getting worse. Soil salinization seriously hampered the development of agricultural and socio-economic development. Improvement and utilization of saline soil has become a hot issue of common concern worldwidely. Using plant physiology and biochemistry or molecular methods to study and solve ecological problems is the ultimate goal of plant physiological ecology. The relationship between plant growth and the environment is an important part of plant physiological ecology. Discovering and nurturing the environment insensitive crops which are defense the adverse environment through the research of mechanism of plant responses to environmental stresses. Therefore, studying the relationship of salt-tolerant plant and environment and the adaptation mechanisms of plant from morphology, physiology and biochemistry is an important way to solve the problem of our country land salinization.The yellow river delta in dongying city of shandong province is to be inshore saline region where the Robinia pseudoacacia and Amorpha fruticosa trees are widely distributed through investigation discovery. Based on this background, in this study, we chose1-year Robinia pseudocacia and Amorpha fruticosa seedlings as the research object. The pot experiment in salt stress simulation method was used to research ecophysiological responses of the two trees to diverse salt stresses by the analysis of the growth, the leaf chlorophyll contents, Chlorophyll fluorescence changes, biomass accumulation and allocation. The aim is to explore ecophysiological responses under salt stress of1-year Robinia pseudoacacia and Amorpha fruticosa seedlings and their salt tolerance differences and ecophysiological adoption mechanism in different habitats. Finally, the theory basis was provided for tree selection,cultivation soil improvement and species introduction in coast saline-alkali soil forestation. At Fanggan Ecological Experimental Station, We used modern ecophysiological equipments and measurements to study its physiological and ecological characteristics under different salt treatments. Four different salt supply levels with a control were conducted in the rainout shelters, Sand culture method was used with stress time setting for40days. The results showed that:Under salt stress, the growth of Robinia pseudoacacia and Amorpha fruticosa seedlings is restrained with the relative growth rate decline, meanwhile, Robinia pseudoacacia was more injured than Amorpha fruticosa, the high salt treatment caused leaf loss serious during the experiment; The results of the leaf chlorophyll fluorescence analysis have shown that the photosynthesis of Amorpha fruticosa plants were stronger suppressed, meanwhile, Robinia pseudoacacia was less affacted, so We suspect that Robinia pseudoacacia seedlings kept its’new leaf photosynthetic capacity by old leaf loss, but, Compared with Robinia pseudoacacia, the Chl a/b in Amorpha fruticosa seedlings is lower, the reasons still needs further research; Under salt stress, biomass allocations were also affected, more photosynthetic products were transferred to belowground biomass, which caused increases of the root mass ratio as well as the root to shoot ratio. Biomass of Robinia pseudoacacia seedlings under salt stress decreased significantly, meanwhile, the root mass ratio of Amorpha fruticosa seedlings was larger, which is consistent with its stronger ability of salt tolerance.