Effect of Drought Stress on Lipid Peroxidation in Soybean Varieties with Different P Efficiency

Soybean cultivars with high phosphorus efficiency adapt to P stress environment easily.Previous studies have focused on the mechanism of soybean’s adaptation to low P stress.But the coupling effect of water and phosphorus on different P efficiency genotypic soybean is less documented.Therefore,pot experiments were conducted in 2007 year,with P high efficient soybean Heihe 27 and P low efficient soybean Heihe 29 as materials,to determine the influence of water and P coupling on lipid peroxidation characters of different genotypic soybean at seedling stage.Two P(applied P and without P)and four water(100%,70%,50% and 30% of the maximum field water holding capability)treatments were designed and endosmosis permeability,O-·2content,malondiaidehyde(MDA)content,relative conductivity,Superoxide dismutase(SOD),peroxide enzyme(POD)activity,catalase enzyme(CAT)activity,proline content,soluble sugar content were determined.As drought stress increased,the MDA,relative conductivity and O-·2content of P high efficient soybean increased and the increasing scope was obviously smaller than that of P low efficient soybean;the decrease scope of SOD,POD and CAT activity of P high efficient soybean was remarkably smaller than that of P low efficient soybean; proline and soluble sugar content of P high efficient soybean increased obviously.The results indicate that antioxidant enzymes are related to drought tolerance and the osmotic adjustment materials are the inherent basis of superior drought tolerance of different phosphorus efficient soybean,and the lipid peroxidation degree of P high efficient soybean is significantly reduced.