铜胁迫对竹叶眼子菜叶片生理指标和超微结构的影响

通过溶液培养试验,研究了不同Cu2 浓度(0、2、4、6和8 mg.L-1)胁迫对沉水植物竹叶眼子菜叶片叶绿素含量、可溶性蛋白含量、保护酶活性、活性氧产生以及细胞超微结构的影响.结果表明:随着Cu2 浓度的增加,竹叶眼子菜叶片总叶绿素、类胡萝卜素和可溶性蛋白含量逐渐下降;超氧化物歧化酶、过氧化物酶逐渐下降,而过氧化氢酶则呈先升后降趋势;超氧阴离子产生速率、过氧化氢、丙二醛和可溶性糖含量均呈上升趋势;不连续聚丙烯酰胺凝胶电泳(SDS-PAGE)显示,Cu2 处理后,引起分子量为60.9、18.8、15.7、22.3和30.0 kDa多肽的表达量减少或消失;电镜观察发现,Cu2 对叶片细胞器的超微结构特别是叶绿体、线粒体和细胞核造成严重损伤;Cu2 对竹叶眼子菜的致死浓度范围在2~4 mg.L-1.

Effects of Cu2+ stress on leaf physiological indice and ultrastructure of Potamogeton malaianus

With solution culture, this paper studied the toxic effects of different concentrations of Cu2+ (0, 2, 4, 6, and 8 mg x L(-1)) on the chlorophyll content, soluble protein content, protective enzyme activities, active oxygen generation, and ultrastructural changes in Potamogeton malaianus leaf. The results showed that with increasing concentration of Cu2+, the chlorophyll, carotenoid and soluble protein contents and uperoxide dismutase (SOD) and peroxidase (POD) activities decreased, catalase (CAT) activity increased first and decreased then, while O2-*, H2O2, MDA and soluble sugar content increased. SDS-PAGE revealed that Cu2+ induced the disappearance or the decrease of the expression amount of four polypeptides with apparent molecular weights of 60.9, 18.8, 15.7, 22.3 and 30.0 kDa. Transmission electron microscopy observation indicated that the higher Cu2+, concentration, the more serious damages the leaf organelles, especially chloroplast, mitochondria and nucleus, suffered. It was concluded that the death of P. malaianus plant under Cu2+ stress was resulted from the destruction of physiological function and structural foundation, and the disorder of physiological metabolism. The lethal concentration of Cu2+ could be 2-4 mg x L(-1).