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Mai B.,Nanjing University of Information Science and Technology | Zheng Y.,Nanjing University of Information Science and Technology | Zheng Y.,Jiangsu Key Laboratory of Meteorological Disaster KLME | Wu R.,Nanjing University of Information Science and Technology | And 3 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2010

Acid deposition is among the primary environmental problems on a global basis. With the winter wheat cultivar YM 12 under field experiment subject to a range of such pollution intensities as pH = 1.5,2.5,3.5,4.5 and 5. 6 (the last being for CK) in the rains, we investigated their stress on nutrition qualities of grains consisting of amino acid, protein, soluble sugar, reduced sugar, starch as well as total acidity so as to provide theoretical basis for preventing and controlling the impact of acid rain on crops in China. Results suggest that for acid rain at pH ≤ 4.5 the synthesis is suppressed of total free amino acid and the inhibition is the stronger, the higher the acidity; the contents of protein (including soluble part and total) decrease progressively as a function of increasing acidity, with greater decline at pH = 1.5; at pH ≤ 4. 5, the synthesis of soluble sugar is inhibited more strongly; at pH ≤ 2. 5, the synthesis of reduced sugar is prevented more significantly; with the increase in acidity in the rain the total acidity and acid-sugar ratio show a tendency of first intensification and then decline, peaking at pH = 3.5; at pH ≤ 3.5 the composition of starch is greatly prevented, affecting amylopection more pronouncedly, thereby resulting in the decrease in the ratio of amylopection to amylase. Source


Zheng Y.,Nanjing University of Information Science and Technology | Zheng Y.,Jiangsu Key Laboratory of Meteorological Disaster KLME | Mai B.,Nanjing University of Information Science and Technology | Wu R.,Nanjing University of Information Science and Technology | And 6 more authors.
Photosynthetica | Year: 2011

Winter wheat is a grass species widely planted in northern and central China, where the increase of aerosols, air pollutants and population density are causing significant reduction in solar irradiance. In order to investigate the adaptation of winter wheat (Triticum aestivum L., cv. Yangmai 13) to low irradiance conditions occurring in the downstream plain of the Yangtze River (China), plants were subjected to four solar irradiance treatments (100%, 60%, 40%, and 20% of environmental incident solar irradiance). Significant increases in chlorophyll (Chl) and xanthophyll (Xan) pigments, and decreases in Chl a/b and Xan/Chl ratios were observed in plants under low light. Light-response curves showed higher net photosynthetic rates (P N) in fully irradiated plants, that also showed a higher light-compensation point. Shaded plants maintained high values of minimal fluorescence of dark-adapted state (F o) and maximum quantum efficiency of PSII photochemistry (F v/F m) that assess a lower degree of photoinhibition under low light. Reduced irradiance caused decreases in effective quantum yield of PSII photochemistry (Φ PSII), electron transport rate (ETR), and nonphotochemical quenching coefficient (q N), and the promotion of excitation pressure of PSII (1 - q P). The activities of the antioxidant enzymes superoxide dismutase and peroxidase were high under reduced light whereas no light-dependent changes in catalase activity were observed. Thiobarbituric acid reactive species content and electrolyte leakage decreased under shaded plants that showed a lower photooxidative damage. The results suggest that winter wheat cv. Yangmai 13 is able to maintain a high photosynthetic efficiency under reduced solar irradiance and acclimates well to shading tolerance. The photosynthetic and antioxidant responses of winter wheat to low light levels could be important for winter wheat cultivation and productivity. © 2011 Springer Science+Business Media B.V. Source

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