Effects of copper stress on antioxidative enzymes, chlorophyll and protein content in Atriplex halimus

Our study showed the effect of Cu on Atriplex halimus grown in hydroponics conditions. The aim of this work was to investigate some enzymatic systems response of this plant to copper stress. Analysis was carried on enzymatic profiles, protein tenor and chlorophyll content of A. halimus leaves. Two months after sowing, plants were subjected to different concentrations of CuSO 4 (50, 500, 1000 and 2000 μM) and samples were analyse after 6, 24 and 48 h. Results demonstrate that chlorophyll content declined progressively with increasing concentrations of copper. In contrast, protein content decreased after 6 h to 38% at 2000 μM CuSO 4 , and then increased after 48 h to 155% at 500 μM CuSO 4 . Non-denaturing polyacrlamide gel electrophoresis (PAGE) revealed three catalase (CAT) isoformes, three superoxide dismutase (SOD) isoformes and five peroxidase (POX) isoformes. One new SOD isoforme and two new CAT isoformes were found as response to high concentration of Cu. The bands density of these enzymes increased with increase of Cu-dose. These results indicate that stress of Cu induced changes in A. halimus metabolism with stimulation of new gene expressions involved in the mechanism of abiotic plant defence. Key words : Atriplex halimus, copper (Cu), oxidative stress, superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), isoenzyme.