铜胁迫对竹叶眼子菜叶片生理指标和超微结构的影响

Effects of Cu^(2+) stress on leaf physiological indice and ultrastructure of Potamogeton malaianus.

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.

With solution culture, this paper studied the toxic effects of different concentrations of Cu^2＋ （0, 2, 4, 6, and 8 mg · L^- 1 ） on the chlorophyll content, soluble protein content, protective enzyme activities, active oxygen generation, and uhrastructural changes in Potamogeton malaianus leaf. The results showed that with increasing concentration of Cu^2＋ , 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^τ , H2O2, MDA and soluble sugar content increased. SDS-PAGE revealed that Cu^2＋ 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 Cu^2＋ 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 Cu^2＋ stress was resulted from the destruction of physiological function and structural foundation, and the disorder of physiological metabolism. The lethal concentration of Cu^2＋ could be 2-4 mg·L^-1.