Protective effect of Mn(III)-desferrioxamine B upon oxidative stress caused by ozone and acid rain in the Brazilian soybean cultivar Glycine max ``Sambaiba{''}

This study aimed to investigate the effects of the Mn complex (Mn(III)-desferrioxamine B (MnDFB)) on oxidative stress in the Brazilian soybean cultivar Glycine max ``Sambaiba{''} following exposure to ozone and acid rain. We determined the suitable dose of MnDFB to apply to G. max seedlings using a dose-response curve. The highest superoxide dismutase (SOD) activity and Mn content in leaves were found upon the application of 8 mu M MnDFB. Thus, G. max seedlings pretreated with 8 mu M MnDFB were individually exposed to ozone and acid rain simulated. Pretreatment with MnDFB reduced lipid peroxidation upon ozone exposure and increased SOD activity in leaves; it did not alter the metal content in any part of the plant. Conversely, following acid rain exposure, neither the metal content in leaves nor SOD enzyme activity were directly affected by MnDFB, unlike pH. Our findings demonstrated that exogenous MnDFB application before ozone exposure may modulate the MnSOD, Cu/ZnSOD, and FeSOD activities to combat the ROS excess in the cell. Here, we demonstrated that the applied dose of MnDFB enhances antioxidative defenses in soybean following exposure to acid rain and especially to ozone. (AU)