Copper Effects on the Antioxidative Responses of Copper-Tolerant Hirschfeldia Incana (L.) Leaves

Abstract

In this study, we investigated the effect of Cu on growth, pigment content, lipid peroxidation, enzymatic and nonenzymatic antioxidant activity in leaves of Cu-tolerant Hirschfeldia incana (L.) and determined Cu contents in its leaves and roots. The plants grown on sand cultures containing various Cu concentrations (100, 250 and 400 mu g g(-1) Cu by DW medium) did not show apparent toxicity symptoms. The leaf fresh weight increased while the dry weight decreased with increasing Cu levels in the media. Cu contents of roots and leaves were also increased but significant decreases in the total chlorophyll content were observed with 100 and 250 mu g g(-1) Cu-treated plants; however, it was increased significantly at 400 mu g g(-1) Cu initial level in culture media. The carotenoid content did not vary in all Cu treatments. The lipid peroxidation was measured as MDA content (malondialdehyde). The MDA content increased significantly at 250 and 400 mu g g(-1) Cu. The analysis of the antioxidative enzymes activity indicated that APX was the most active enzyme in the leaves of H. incana. The CAT activity was increased significantly at 250 mu g g(-1), and it decreased quickly at 400 mu g g(-1). Any significant changes did not occur with respect to SOD and GPOD activities. Non-protein thiols, ascorbate and dehydroascorbate as well as proline content were increased significantly at 250 and 400 mu g g(-1) Cu.