The Response Of 2-Cys Prx Transgenic Leaves Of Tobacco Plants To Atmosphereic SO₂ Deposition

Recently, with the development of social economy, energy consumption and pollutant emissions continued to increase, as the result environmental pressure increased all the time, the content of SO2 emissions from stationary sources such as smelting power generation and coal increased significantly atmospheric PM2.5 and precipitation acidity had become the seriously environmental problems. China acid rain area had become one of the world three biggest area after Europe and North America, In this situation, we need scientific and effective measures to control the pollution of acid rain. To improve the ability of plant resistance to acid rain, this research selected the wild tobacco "LJ911" and the 2-Cys Prx transgenic tobacco as the object. To analyze the response of 2-Cys Prx transgenic tobacco to SO2 deposition, simulated SO2 was obtained by mixing Na2SO3 and NaHSO3 solutions firstly, then the change of biomass, enzyme activity and relevant florescence parameters were measured as evaluation indicators. The results showed as follows:1. Simulated SO2 deposition reduce the growth and development of leaves and roots in seedlings of both wild wild tobacco and 2-Cys Prx transgenic tobacco. The degree of persecution was enhanced by increasing the concentration of SO2. The persecute effect of SO2 was lower than wild tobacco on the growth and development of leaves and roots from 2-Cys Prx transgenic tobacco.2. In the condition of simulated SO2 deposition, the content of MDA was accumulated and the enzyme activities of SOD and POD were increased in tobacco leaves. However the content of MDA was lower in 2-Cys Prx transgenic tobacco. Results showed that the overexpression of 2-Cys Prx gene could relived the oxidative hazard on tobaccos exposed to SO2.3. In the condition of simulated SO2 deposition the photosynthetic apparatus in seedlings of wild tobacco was damaged seriously, but 2-Cys Prx gene had strong antioxidant activity, it can scavenge superoxide anions generated by photosynthesis composed SO2, and relieve oxidative damage of SO2 on chlorophyll in green plant.2-Cys Prx gene could relieve the inhibition effect of SO2 on photosynthesis to a certain extent.4. Simulated SO2 deposition reduced the activity of PS Ⅱ in leaves of tobacco and reduce the speed of photosynthetic electron transport from PS Ⅱ reaction center to QA-, QB- and PQ depot. However the degree of speed cut of 2-Cys Prx transgenic tobacco was smaller than wild tobacco. Results showed that 2-Cys Prx gene could enhance the efficiency of the rest reaction center and promote energy transport in electron transport chain, so it could provide tobacco seedling exposed to SO2 with enough energy.5.Results showed that the ΦPSⅡ used for photochemical reaction was reduced, this phenomenon might are caused by the attenuation of light and pigment in leaves or by light renection, which decreased photochemical efficiency of wild tobacco leaves. Under low light density, the ΦNF of two samples’ seedling leaves inactivation PS Ⅱ reaction center were lower than natural light and Φf,D which was depend on the proton gradient on both sides of thylakoid membrane and xanthophyll cycle were higher than natural light. The increasing range of both quantum yield in 2-Cys Prx transgenic tobacco seedling leaves were higher than wild tobacco. Results showed that two samples’ seedling leaves could maintain the reaction centers’ normal function through xanthophyll cycle and heat dissipation exposed to low light density; 2-Cys Prx gene overexpression could reduce the stress of low light density to wild tobacco to relatively maintain the reaction centers’ normal function.