污染食物喂养实验中铜对白符跳毒性的连续监测

Acute Toxicity Tests of Cu Pollution on Folsomia candida of Collembolan

土壤弹尾目昆虫是土壤环境的重要指示生物,在污染环境的生态评估研究中日益受到重视。本文的污染食物喂养实验的连续观测结果显示,F.candida成虫无死亡,生长率和繁殖率随着酵母食物中Cu浓度的增加而显著减小(21天生长率:R2=0.930 2,F1,7=25.2,p<0.01;繁殖率:R2=0.945 9,F1,7=17.2,p<0.01),暗示F.candida生长率和繁殖率是相对死亡率更敏感的指示重金属污染环境的指标参数。在较高Cu暴露浓度下,随着暴露时间的延长,F.candida的生长率相对对照降低更加明显(p<0.01),说明暴露时间和暴露浓度一样对F.candida的生长有明显的负作用。F.candida产卵时间相对对照发生了延迟现象(F1,7=3.69,p<0.05)。F.candida体内Cu的积累与食物中Cu浓度呈明显的剂量-效应关系,并且在高的Cu暴露浓度下,F.candida体内Cu的积累可以达到较高的程度,说明F.candida可能对Cu具有较高的耐受性,这些可能是培养皿食物暴露实验中导致F.candida成虫的生长率和繁殖率明显降低以及F.candida产卵时间发生延迟现象的内在原因。

Folsomia candida is commonly used in the bioassays as a representative collembolan species because of its large proportion of biomass in edaphic ecosystems and important index creature in soil environment. This research results showed that no mortality in E candida was found in food exposure test, and significant effects of Cu on the growth and reproduction ore candida were observed in food exposure （Growth 21 days R2 = 0.930 2, F1.7 = 25.2, p〈0.01; Reproduction： R2 = 0.945 9, F1.7 =17.2, p〈0.01）, and dose-effect relation models of population characteristics ore canclida against Cu in soil and food exposure were established, thus the parameters such as reproduction and growth rates were more sensitive to Cu in food exposure test than mortality. The longer exposure time was, the more significantly the growth rates reduced at high Cu exposure concentrations compared to the control during continuously monitoring （p〈0.01）, and the appearance of eggs delayed at the highest exposure concentrations （F1.7 = 3.69, p〈0.05）, suggesting that exposure time and Cu exposure concentration also had negative effect on E canclida. Ecandida can accumulate Cu in high concentration when exposed to high Cu concentrations, and significant toxic effects of Cu in F. candida on the reproduction of F. candida were observed （R2 = 0.810 9, p〈0.01）, indicating E candida had a high resistance to Cu, which might be reason of the significant reduction of growth and reproduction and the delay of oviposition.