镉胁迫对小麦叶片细胞膜脂过氧化的影响

镉胁迫使植物体内活性氧自由基清除系统的功能降低，造成细胞内H₂O₂积累，抗坏血酸过氧化酶和谷胱甘肽还原酶活性下降，内源抗氧化剂抗坏血酸和谷胱甘肽含量减少，小麦叶片的组织自动氧化速率显著提高。细胞内丙二醛的积累表明，膜脂过氧化发生和膜系统受到损伤。推测小麦镉伤害过程中，活性氧自由基代谢失衡造成的膜脂过氧化起着重要作用。

Effects of cadmium stress on lipid peroxidation in wheat leaves.

Lipid peroxidation is one of the most deteriorative reactions damaging cellular membrane.For further understanding the lipid peroxidation in wheat leaves under cadmium stress, hydrogen peroxide scavenging system was studied. Germi nating seedlings of wheat ( Tritium aestivum) were treated with different concentrations of cadmium acetate (0.05, 0.1,0.3, 0.5 and 1.0 mmol/L). Cadmium stress significantly enhanced the accumulation of H 2O 2 in cells. Activities of ascorbate peroxidase (EC 1.11.1.7) and glutathione reductase (EC 1.6.4.2) decreased apparently , and contents of ascorbic acid and glutathione also dropped under Cd stress. Furthermore, the rate of tissue autoxidation in leaves was higher than that of the control, which indicated lipid peroxidation of cellular membrane was stimulated by endogenous active oxygen radicals. The results suggest that effects of cadmium on wheat leaves is achieved by excessive accumulation of active oxygen radicals resulted from the degradation of the radical scavenging system.