Cr^6＋、Pb^2＋、Cd^2＋胁迫下条斑紫菜保护酶系统的响应

Effects of the Stress of Cr^(6+),Pb^(2+),Cd^(2+) on Protective Enzyme System in Porphyra yezoensis

研究了不同Cr6+、Pb2+、Cd2+处理浓度对条斑紫菜(Porphyra yezoensis)超氧化物歧化酶(SOD)、过氧化物酶(POD)、总抗氧化力(TAC)等保护酶系统的效应作用。结果表明,SOD、POD、TAC活性均随着处理浓度的增加,表现为先升高、后降低的总体趋势;但可溶性蛋白含量均比对照组高。Cd2+处理浓度为0~10mg/L、Cr6+浓度为0~20mg/L、Pb2+浓度为0~30mg/L时,SOD、POD、TAC应激性升高达最高值,之后迅速降低。相关指数分析显示,POD对Cr6+、Pb2+、Cd2+较SOD敏感。TAC为衡量机体抗氧化系统功能状况的综合性指标,SOD、POD在抗氧化系统适应重金属胁迫中起主要作用。条斑紫菜对重金属污染有较强的耐受性,相比较而言,Cd2+的毒性最高,Pb2+次之,Cr6+最弱。POD、SOD、TAC可以作为条斑紫菜受环境重金属污染胁迫的生化生理指标。

A survey was conducted to investigated the effects of the stress of heavy metal on superoxide dismutase （SOD）, peroxide （POD） and total antioxidant capacity （TAC） in Porphyra yezoensis. P. yezoensis was cultivated for 6 d in seawater containing one of three kinds of metal ion, Cr^6 ＋ , Pb^2 ＋ and Cd^2 ＋ , with concentrations of 0 mg/ L , 10 mg/L, 20 mg/L, 30 mg/L, 40 mg/L and 50 mg/L respectively. The activity of SOD, POD and TAC of P. yezoensis were increased at first and then decreased as the concentrations of metal ion increase, with the peak at 20 mg/L Cr^6＋ , 30 mg/L Pb^2＋ and 10 mg/L Cd^2＋ , respectively. Based on the results of relative exponential analysis, POD is more sensitive to these three metal ion than SOD. TAC was the comprehensive index for measuring the antioxidant system function in P. yezoensis, while SOD and POD played a major role in adapting to the stress of heavy metal. In conclusion, Cd^2＋ has the strongest toxicity on P. yezoensis, followed by Pb^2＋ , and Cr^6＋ the weakest. P. yezoensis is quite tolerable to heavy metal pollution.