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The emission of industrial wastes brought to environment deterioration after long time.Heavy metal lead was one of industrial wastes.A greats of dose lead may bring poison to plants.Lead could block the development and growth of plants,and reduced photosynthesis,rising rate,which lead to receded production.SA（salicylic） had functions on resist disease,cold tolerance,hot tolerance and drought tolerance.So we took spinach as test material,studied lead stress it and SA relaxed mechanism.The main result was as follows:1.With Pb2+ concentration increasing,the leaf area drop off,and root activity and growth quantity was reduced.Especially,spinach was severity restrained under high concentration Pb2+ treatments,the more high of Pb2+,the smaller of growth quantity.Less than 400 mg.L-1 Pb2+ treatment,in addition to SA can revive Pb2+ stress,which showed that the increasing of dry and fresh weight,root activity and leaf area,but SA has no revived function under 600 mg.L-1 pb2+.2.During lead treatment primary,protected enzyme activity of spinach leaf rapidly increased,the more high of Pb2+,the more enzyme activity. while protected enzyme activity of spinach leaf reduced with high Pb2+ treatment after that,and membrane pledge excessive oxidation was pricked up, which showed that contents of MDA and electrolytic relative leakage were increased. At last,protected enzyme activity of spinach leaf was lowest under high Pb2+ treatment.3.Pb2+ bring spinach to saturation stress,which showed that soluble sugar and soluble protein content were increased in spinach leaf,but them were decreased with delay treatment,especially proline content of leaf was always drop.Under 400 mg.L-1 Pb2+ treatment,in addition to SA can revived Pb2+ stress,which can improve saturation adjustment and revived stress. However,in addition to SA could not revived Pb2+ stress less than 600 mg.L-1Pb2+ treatment.4.Pb2+ reduced stomata conduction photosynthetic rate of spinach.Under 400 mg.L-1 Pb2+ treatment,in addition to SA can revived effects of Pb2+ stress photosynthetic organ,such as enhanced chlorophyll a/b and photochemistry efficiency,which improved photosynthetic rate of spinach.While in addition to SA could not revived photosynthetic rate under 600 mg.L-1Pb2+ treatment.5.Vc,total oxalic acid and nitrate content of spinach leaf were reduced under Pb2+ treatment.In addition to SA not only receded lead content of root, stalk and leaf and enhanced Vc,but revived lead stress,so decreased absorbed quantity of lead during people eating spinach.
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