Effects of Lead Stress on Antioxidant Enzyme Activity of Broussonetia papyrifera Seedlings

Using a potted planting experiment and lead-contaminated soil with different contamination degrees(100,300,500,700,and 1 000mg/kg)as culture media,the effect of lead stress on antioxidase activity in the annual seedling leaves of Broussonetia papyrifera was studied. The results showed that,along with the increasing in lead ion concentration in culture media,the activities of superoxide dismutase and catalase in Broussonetia papyrifera seedling leaves increased firstly and then decreased,while the activity of peroxidase showed a general increasing trend as the lead concentration increased.Moreover,within the concentration range of the experiments,variations in the activity of these three enzymes were not significantly different compared to that in the control group,indicating that Broussonetia papyrifera had better lead tolerance and could be used as a restoration plant for lead-contaminated regions.