Effects Of Acid Rain On Growth And Physiological Characteristics After Flowering In Wheat

China is one of the hardest-hit acid rain areas. Not only acid rain area is large,but also rainfall acidification rate is also high. The main acid rain areas distribute in the vast areas south of the Yangtze river, the southern most cities and regions encounter the acid rain. Wheat is an important crop, which is widely planted in southern China. wheat production directly affect our country's food security. Wheat is sensitive to adversity from flowering to maturity filling. At the same time the period is also the key to determine yield and quality of wheat. In order to find different inherent response mechanisms between two types of wheat under acid rain stress. The reference basis and technical support will be provided to plant the wheat varieties resistant to acid rain and select breeds. A pot experiment was conducted to study the effects of different pH acid rain antioxidant system, carbon, nitrogen, sulfur metabolism and yield and quality in Wennong 17 and Yangmai 15. The results were as follows:1.Acid rain significantly reduced photosynthesis and chlorophyll content, especially lower chla. Acid rain reduced the biomass of leaves, stems and sheaths, ear of two varieties of wheat, improve the amounts and remobilization rate of pre-anthesis stored assimilates and total amount of pre-anthesis stored assimilate, reduced remobilization of pre-anthesis stored nitrogen. Acid rain reduced the grain yield of two wheat cultivars, significantly reduced numbers of grain per panicle and grain weight in Wennong 17, reduced grain numbers in Yangmai 15. Comparied between different species, the impact in Wennong 17 is greater than Yangmai 15. With increasing acidity, the greater the impact on the above indicators.2. Acid rain inhibited the activity of SOD, improved POD and APX activity of two wheat varieties in the late stage of filling. Acid rain improved CAT activity in Yangmai 15. Acid rain reduced the contents of HAsA, GSH and carotenoid in leaf. Generation rate of reactive oxygen species significantly accelerated and MDA content increased under acid rain stress. Membrane lipid peroxidation was significantly enhanced, which caused severe damage to the plant. The higher the acidity became, the bigger oxidative system harmed. Acid rain had a bigger influence on Wennong 17 in antioxidant system than on Yangmai 31.3. Acid rain decreased the total soluble sugars and sugar content in leaf and increase the post-filling total soluble sugar and sucrose content in stem and sheath. Acid rain reduced SPS activity in leaf, reduced SS and ADPGPPase activity in grains. At the same time, the supply of sugar and was reduced. Acid rain reduced content of starch and amylopectin content and ratio of amylopectin and amylase in grains. Acid rain had a bigger influence in Wennong 17 about Carbon metabolism than in Yang 31. Acid rain decreased soluble protein content in leaf, increase the free amino acids in middle and later filling stage periods post-filling, improved the mature grain amino acid and protein content. Acid rain inhibited NR activity. GS activity in leaves was improved on Yangmai 31,but Wennong 17 showed just the opposite. Compared with wennong 17, acid rain enhanced nitrogen metabolism of Yangmai 15, high acidity led to the higher impact. Acid rain increased albumin and globulin contents, while decreased glutenin content and ratio of glutenin and gliadin. Acid rain increased protein yield in Wennong 17, while Yangmai 15 performed opposite. Acid rain increased and essential amino acids and disulfide bonds content in grains protein of two varieties of wheat. Acid rain increased the sulfur aminos acid in grains and SAT and OAS-TL activity on Yangmai 31, but had a small effect on Wennong 17. Acid rain improved the nutritional quality of two varieties of wheat, high acidity led to the higher impact, improved processing quality of Wennong 17, but may brought an adverse effects on Yangmai 15.