Lead-Induced Oxidative Stress and Defense Response of Soybean ‘DT84’

Abstract

     Oxidative stress in root of soybean [(Glycine max (L.) Merr.] cv. DT84’ was induced by exposure to Pb²⁺ ion. The reactive oxygen species (ROS) products such as hydrogen peroxide (H₂O₂), superoxide anion radical (O₂ .-) were rapidly produced 6-12 hours after treatment with Pb^2+. The enhancement of the ROS was closely dependent upon concentrations of Pb²⁺. An increase in content of thiobarbituric acid reactive substances (TBARS) - product of membrane lipid peroxidation, and the high percentage of injury (13.89-25.03%) indicated that the cellular damage was resulted from oxidative stress. The induction of superoxide dismutase (SOD) and catalase (CAT) in roots of soybean cv. DT84 as the defense response of soybean via these antioxidative enzymes reduced the concentration H₂O₂ and O₂ .- 24 hours following Pb²⁺ treatment, therefore, contributing to control oxidative stress in soybean roots.