Cd2+污染水质对水花生根系抗氧化酶活性和超微结构的影响

在不同浓度Cd^2 污染下，水花生根中超氧化物歧化酶(SOD)和过氧化氢酶(CAT)的活性呈现先升后降的变化，但达到最大值时的Cd^2 污染浓度，SOD的更低，过氧化物酶(POD)的活性和可溶性蛋白含量呈现持续下降的变化趋势，可溶性蛋白的含量受Cd^2 的毒害更大。随着Cd^2 污染浓度的增加和胁迫时间的延长，根尖细胞中高尔基体消失，线粒体嵴突膨胀、变形及空泡化，细胞核扭曲成不规则形，核染色质凝集，这些变化反应在功能上表现为膜脂过氧化、能量供应不足，蛋白质合成受阻而含量下降，最终导致死亡。各项结果与Cd^2 皆表现出明显的剂量效应关系，污染浓度愈大毒害程度愈深。

Effects of Cd2+ Polluted Water on the Activities of Antioxidant Enzymes and Ultrastructure in Roots of Alternanthera philoxeroides

The roots of Alternanthera philoxeroides make a quick response to different concentrations of Cd 2+ polluted water. The activities of SOD and CAT increased rapidly in the low concentration of Cd 2+ and then decreased with the rise of pollution. But POD activity and the content of soluble protein all declined continually in the series of culture concentration. Ultrastructural observation showed that the extent of ultrastructural damage was much more serious with the increasing of pollutant concentration and longer time of stress, such as disappearing of golgi apparatus; swelling of cristae, deforming and vacuoting of mitochondria; distortion of nucleus and condensation of chromatin. It may be related with peroxidation of membrane lipid, the shortage of energy and produce of protein restrained. All indexes showed an evident correlation between dose and effect, the more Cd 2+ pollution, the more serious damage.