Hg^(2+)对花翅摇蚊Chironomus kiiensis幼虫口器致畸作用及抗氧化酶活性的影响

Effect of Hg^(2+) Exposure on Teratogenesis Mouthparts and Antioxidant Enzyme Activity in Larval Chironomus Chironomus kiiensis

在水温(17.0±1.0)℃和16h光∶8h暗的光周期下,采用加标于沉积物法研究Hg^(2+)对花翅摇蚊Chironomus kiiensis幼虫口器的致畸作用和抗氧化酶活性的慢性毒性影响。将4龄摇蚊幼虫暴露于0.002mg·L^(-1)、0.004 mg·L^(-1)、0.008mg·L^(-1)、0.016mg·L^(-1)、0.032mg·L^(-1)、0.064mg·L^(-1)、0.128mg·L^(-1)和0.256mg·L^(-1)8个Hg^(2+)浓度梯度下,测定摇蚊幼虫组织匀浆超氧化物歧化酶(SOD)和过氧化氢酶(CAT)的活性。结果表明:Hg^(2+)显著影响花翅摇蚊幼虫体组织SOD和CAT活性,且与Hg^(2+)暴露浓度呈显著浓度-效应关系(P<0.05)。Hg^(2+)暴露30d后,摇蚊幼虫的大颚长度与Hg^(2+)暴露浓度之间也呈极显著正相关性(P<0.01)。该结果说明在低浓度Hg^(2+)的胁迫下,摇蚊幼虫形态结构、生理功能发生了显著改变,可用该幼虫的形态结构、生理功能指标作为监测水体Hg^(2+)污染及判定水环境质量的生物学指标。

Chronic toxicity of mercury to larvae of chironomus Chironomus kiiensis was studied by using standard-sediment method in a laboratory. The activities of superoxide dismutase（SOD）and catalase（CAT）related to antioxidant enzymes and teratogenic mouthparts were monitored in the homogenate of tissues in the 4 instar larvae of the chironomus exposed to Hg-（2＋）concentrations of 0.002 mg·L-（-1）, 0.004 mg·L-（-1）, 0.008 mg·L-（-1）, 0.016 mg·L-（-1）, 0.032 mg·L-（-1）, 0.064 mg·L-（-1）, 0.128 mg·L-（-1）and 0.256 mg·L-（-1）. The results showed that Hg-（2＋）led to obvious effects on the activities of SOD and CAT, with significant concentration-response relationship（P 0.05）.The chironomus larvae exposed to Hg-（2＋）for 30 d showed a significant positive correlation between the mandibular length in mouthparts and the exposure concentration of Hg-（2＋）（P 0.01）. The findings indicate that the morphological structure and physiological function of chironomus larvae can be used as an important biological indicator for monitoring of water pollution of Hg-（2＋）since the low concentration of Hg-（2＋）stress has led to significantly change in morphology and physiology of chironomus larvae.