Nickel-induced oxidative damage and antioxidant responses in Zea mays shoots

Zea mays (cv. LG 23/01) seedlings precultured in hydroponic culture for seven days were treated with 250 μM NiCl2 for five days. Several metabolic parameters representative of oxidative damage and antioxidant activity in shoots were regularly studied after the metal treatment. Two days after Ni-application, membrane lipid peroxidation intensified. A stimulation of guaiacol peroxidase (EC 1.11.1.7) activity was recorded. Analysis of the profile of anionic isoenzymes of guaiacol peroxidase revealed quantitative changes occurring during Ni-exposure. Superoxide dismutase (EC 1.15.1.1) activity was stimulated early and transiently. Later, the activities of ascorbate peroxidase (EC 1.11.1.11), catalase (EC 1.11.1.6) and glutathione reductase (EC 1.6.4.2) increased. The results are discussed with regard to nickel-induced oxidative stress and potential antioxidant reactions.