Oxidative stress and some antioxidant systems in acid rain-treated bean plants - Protective role of exogenous polyamines

The effect of simulated acid rain (AR) (pH 1.8) on H2O2 and malonyldialdehy de (MDA) levels and activities of peroxidase and catalase in bean plants we re investigated. The influence of exogenous polyamines spermidine and sperm ine on these parameters was also studied. AR treatment induced lipid peroxi dation and increased level of H2O2 in leaves. Pretreatment with spermidine and spermine prevented these changes. The protective effect of spermine was higher than that of spermidine. The impact of polyamines could be attribut ed to their acid neutralizing and antioxidant effects, as well as to their ability to stabilize membranes by associating with negatively charged phosp holipids. It was also found that AR significantly increased peroxidase and decreased catalase activities at the first hours after treatment. Later, bo th enzyme activities were enhanced that could contribute to the scavenging and detoxification of active oxygen species. (C) 2000 Published by Elsevier Science Ireland Ltd. All rights reserved.