铜污染对三叶草幼苗生长及活性氧代谢影响的研究

通过水培实验研究了重金属铜(Cu)污染对三叶草(Trifolium pratense)幼苗生长及活性氧代谢系统的影响。结果表明，低浓度Cu污染(<10mg·L^-1)对三叶草幼苗生长无明显抑制现象，甚至促进幼苗生长，植株干重、鲜重和叶片可溶性蛋白及叶绿素含量均略微升高，丙二醛(MDA)水平降低，活性氧清除系统内超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性均略微升高，保护酶系统仍保持平衡.但随Cu浓度(10～100mg·L^-1)增加则显示出一定的负效应，三叶草幼苗与对照组相比，植株矮小，须根短且数目少，植株干重、鲜重和可溶性蛋白含量均明显减少，叶片发黄，叶片色素含量下降，并随Cu浓度的增加而变化更显著。同时，随Cu浓度增加，叶片细胞膜透性增大，电导率显著升高，MDA水平上升，且活性氧清除系统遭到破坏，保护酶系统失衡，SOD和CAT活性显著下降，分别降低了26．7％和71．3％，而POD活性却明显上升，比对照升高了10．6倍。

Effect of copper pollution on seedling growth and activate oxygen metabolism of Trifolium pratense

The effect of copper (Cu) pollution on the seedling growth and activate oxygen metabolism of Trifolium pratense was studied by water cultivation experiments. The results showed that under low concentration of Cu (< 10 mg.L-1), the growth of Trifolium pratense seedlings could be improved, their fresh/dry weight and the contents of soluble protein and chlorophylls in leaves increased slightly, the MDA content of leaf cells decreased, the activities of SOD, CAT and POD in the activate oxygen metabolism system slightly increased, and the balance of protective enzyme system was hold. However, with the increase of Cu concentration (10-100 mg.L-1), there existed an obvious negative effect on the growth of Trifolium pratense seedlings. The seedlings under high concentrations of Cu were shorter and smaller, their fibrous roots were shorter and fewer, and their fresh/dry weight and the contents of soluble protein and chlorophylls in leaves decreased drastically. With the increase of Cu concentration, the membrane penetration, electric conductivity and MDA content of leaf cells increased. Furthermore, the activate oxygen metabolism system was destroyed, the balance of protective enzyme system was broken, the activities of SOD and CAT decreased by 26.67% and 71.31%, respectively, while the POD activity increased by 10.6 times.