Effects on Photosynthesis of Mango Seedlings Treated with Calcium under Soil Drying Stress
Jia Husen, Cai Shiying,Li Dequan, and Han Yaqin (College of Life Science, Shandong Agricultural University, Taian 271018; College of Agriculture, South China University of Tropical Agriculture; Department of Biology, Liaocheng Teacher's College )
Photosynthesis of mango seedlings treated with calcium were studied under soil drying stress. The results indicated, at the beginning of the stress period (0-8 day), calcium could accelerate soil water ahsorption, improve leaf water condition, reduce AsA decomposition and prevent H_2O_2 accumulation in leaves. In addition, calcium could keep leaf SOD high activity and retard O_2~- over producing. Thus leaf lipid oxidations and pigment damages were effectively restricted and seedlings could keep high photosynthetic abilities. With dry stress going on, mango seedlings treated with calcium suffered from severe soil water deficiencies. The O_2 produced with high rates and caused great damages on photosynthetic pigments and lipid oxidations, which led photosynthetic rate to drop sharply. Moreover, Chl b contents increased during soil drying stress and analysised which was possible good at adaptation and resistance severe dry condition for mango seedlings.