麝香酮和镉单一与复合污染对金鱼藻的生态毒理效应研究

为从生物化学角度探讨一种新型污染物———麝香酮与镉(Cd)单一和复合污染的生态毒理效应,以金鱼藻(Ceratophyllum demersum L.)为研究对象,分析了不同浓度麝香酮和Cd在水中单一与复合污染对金鱼藻叶片中抗氧化系统酶,包括超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT),脂质过氧化最终产物丙二醛(MDA),可溶性蛋白(SP)和叶绿素含量的影响.结果表明:在单一麝香酮和Cd暴露下,SOD活性第1天均显著降低,而第7天在低浓度污染物的胁迫下呈升高趋势;金鱼藻受麝香酮和Cd胁迫的第1天,POD酶活性分别呈升高和降低趋势;麝香酮浓度为0.05mg·L-1或Cd浓度为0.01mg·L-1时,金鱼藻叶片中的CAT活性变化表现为显著的毒物兴奋作用;用两种污染物单一或复合处理第7天,金鱼藻叶片中的MDA和叶绿素含量可以作为评价麝香酮或/和Cd污染水体环境的敏感指标;SP在这两种污染物胁迫下处于能量及脂蛋白的补偿和应激蛋白的合成两方面的得失平衡过程中,故其含量与处理浓度之间无显著相关关系;复合污染中低浓度的麝香酮和Cd复合对金鱼藻表现为拮抗作用,高浓度的复合表现为相加或协同作用.

Single and Joint Effects of Musk Ketone and Cadmium on Coontail (Ceratophyllum demersum L.)

To investigate the single and joint ecotoxicological effects of musk ketone or/and cadmium (Cd)at biochemical levels, the activity of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD)and catalase(CAT), and the contents of malondialdehyde(MDA), soluble protein(SP)and chlorophyll of coontail(Ceratophyllum demersum L.) under the single and joint exposures of musk ketone and Cd were determined in our study. Results indicated that there was a decrease in SOD in the leaves of coontail exposed to either of musk ketone or Cd on the first day of exposure. But after 7 days of exposure, antioxidant system began to clear reactive oxygen species(ROS)which was generated by the oxidative stress of musk ketone or Cd, so the activity of SOD was induced when the concentrations of the pollutants were lower. Unlike SOD activity, the activity of POD was obviously induced and inhibited by the single stress of musk ketone and Cd on the first day of exposure, respectively. When the coontail were exposed to musk ketone with the concentration of 0.05mg·L-1 and Cd with the concentration of 0.01mg·L-1 attributed, hormesis effected on the change in the activity of CAT obviously. And hormesis was diluted when the coontail exposed to the joint stress, when there was an increase followed by a decrease with the increase of Cd concentration. After 7 days of exposure, the contents of MDA and chlorophyll in the leaves of coontail, exposed to either single or joint stress of musk ketone or/and Cd, had positive correlations with the concentrations of the pollutants, so that they can be used as sensitive indexes for the single and joint stress of musk ketone or/and Cd. The compensation for loss of energy and lipoprotein and the synthesis of the reactive protein acted on the content of SP simultaneously, so the result of the equilibrium showed that there was no obvious correlation between the change in the content of SP and that of the pollutions. The joint effects ranged from antagonism to synergism or addition as the pollutant concentrations increased.