镉胁迫对水车前叶片抗氧化酶系统和亚显微结构的影响

摘要

Investigation was made of effect of simulated Cd2＋ pollution on the antioxidase system and ultrastructure of the cells of Ottelia alismoides(L.)Pers.leaves,mainly chloroplasts,mitochondria and cell nucleus. It was found that with increase in the stress,superoxide dismutase(SOD)activity and soluble protein content decreased drastically,while malonyl(MDA)increased;and that the activity of peroxidase(POD)and catalase(CAT)peaked at 0.1mg/L of the pollutant and declined afterwards. Electronic microscopic observation showed that at the early stage of the toxication,chloroplasts and mitochondria were swelling up;and thylakoids vacuolized apparently. Higher concentration of Cd2＋ aggravated the damage,making chloroplast membranes disappear and chloroplasts disintegrate,mitochondrion mesenchyme dissolve and mitochondria be on the verge of disorganization,and nucleolus chromatin agglutinate and merge into cytoplasm. Cd2＋ pollution not only destroys the plant's antioxidase system,but also causes irreversible damage to its ultrastructure,thus leading the cells to death.%报道了模拟镉污染对水车前叶片抗氧化酶系统的影响及对叶细胞超微结构，主要是叶绿体、线粒体和细胞核的损伤情况。随胁迫程度的增大，超氧化物歧化酶活性和可溶性蛋白含量下降明显，丙二醛含量则上升，过氧化物酶和过氧化氢酶活性在0.1 mg/L浓度处达到最高后呈下降趋势。电镜观察结果表明：毒害初期，叶绿体和线粒体膨胀，类囊体明显空泡化；高浓度镉处理使破坏程度加重，叶绿体被膜消失和叶绿体解体；线粒体间质溶解，濒临解体；细胞核染色质凝集并散入细胞质中。由于镉胁迫破坏了植物的抗氧化酶系统，并对超微结构造成不可逆损伤，最终使细胞死亡。