铜污染对玉米幼苗的毒性及其机制研究

Toxicity of copper to maize seedlings and its mechanism of action

用不同质量浓度的Cu处理玉米幼苗,分析了Cu毒性对幼苗生长的影响和体内氧化损伤情况,并采用分步提取技术研究了玉米幼苗地上部分中Cu的化学形态分布.结果表明加Cu处理明显抑制了玉米的生长和发育,并引起肉眼可见的伤害.铜胁迫导致玉米幼苗叶片中抗氧化酶系统中酶活性的变化,在本研究的Cu处理质量浓度范围（5～160 mg/L）内,随着Cu质量浓度的增加,幼苗叶片中的超氧化物歧化酶（SOD）、过氧化物酶（POD）活性升高,过氧化氢酶（CAT）活性先升高后下降.铜胁迫还会导致植物体内的氧化损伤,丙二醛含量随Cu处理质量浓度提高而增加.玉米幼苗累积的Cu在体内以不同的化学形态分布,通过体内结合机制降低体内Cu的移动性是玉米幼苗抵抗Cu污染危害的重要机制之一.

Hydroponics experiments were used to investigate the toxic effects of copper（ II ） on maize seedlings and the mechanism responsible. When treated with different concentrations of copper（ II ）, the growth and the oxidative damage of maize seedlings was monitored and a sequential extraction technique was used to study the distribution of chemical forms of Cu2＋ in the shoots of maize seedlings. The results showed that the growth inhibition of maize seedlings increased with increasing Cu2＋ concentration and the presence of Cu2＋ led to macroscopic scars. Copper （ II ）-induced stress leads to changes in In the mass concentration range of Cu2＋ enzyme activity in the antioxidant enzyme system of maize seedling employed （5 -160 mg/L）, the activities of superoxide dismutase blades. （SOD） and peroxidase （POD） increased and the activity of catalase （CAT） initially increased and then decreased with in- creasing Cu2＋ concentration. Copper（ II） also results in oxidative damage in the plants, and the content of malon- dialdehyde increased with increasing concentration of Cu2 ＋ . The Cu2 ＋ accumulated in maize seedlings in different chemical forms, and one of the main mechanisms to resist Cu2 ＋ pollution is by decreasing the mobility of Cu2 ＋ in plants by means of the binding mechanism.