College of Natural Resources and Environment, Northwest A&F University, Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Shaanxi Province, Yangling, China.
Environ Toxicol Chem. 2013 Apr;32(5):1109-16. doi: 10.1002/etc.2152. Epub 2013 Apr 2.
The present study explored the joint effects of Cu and Se pollution mechanisms on soil enzymes to provide references for the phytoremediation of contaminated areas and agricultural environmental protection. Pot experiments and laboratory analyses were carried out to study the individual and combined influences of Cu and Se on soil enzyme activities. The activities of four soil enzymes (urease, catalase, alkaline phosphatase, and nitrate reductase) were chosen. All soil enzyme activities tested were inhibited by Cu and Se pollution, either individually or combined, in varying degrees, following the order nitrate reductase>urease>catalase>alkaline phosphatase. Growing plants stimulated soil enzyme activity in a similar trend compared with treatments without plants. The joint effects of Cu and Se on catalase activity showed synergism at low concentrations and antagonism at high concentrations, whereas the opposite was observed for urease activity. However, nitrate reductase activity showed synergism both with and without plant treatments. The half maximal effective concentration (EC50) of exchangeable fractions had a similar trend with the EC50 of total content and was lower than that of total content. The EC50 values of nitrate reductase and urease activities were significantly lower for both Se and Cu (p<0.05), which indicated that they were more sensitive than the other two enzymes.
本研究探讨了 Cu 和 Se 污染机制对土壤酶的联合作用，为污染区的植物修复和农业环境保护提供参考。通过盆栽试验和实验室分析，研究了 Cu 和 Se 单独及联合作用对土壤酶活性的影响。选择了四种土壤酶（脲酶、过氧化氢酶、碱性磷酸酶和硝酸还原酶）进行研究。所有测试的土壤酶活性均受到 Cu 和 Se 污染的抑制，无论是单独还是联合作用，其抑制程度依次为硝酸还原酶>脲酶>过氧化氢酶>碱性磷酸酶。与无植物处理相比，植物生长以相似的趋势刺激土壤酶活性。Cu 和 Se 对过氧化氢酶活性的联合作用在低浓度下表现为协同作用，在高浓度下表现为拮抗作用，而脲酶活性则相反。然而，硝酸还原酶活性在有植物和无植物处理下均表现出协同作用。可交换态的半数最大有效浓度（EC50）与总量的 EC50 趋势相似，且低于总量的 EC50。Se 和 Cu 对硝酸还原酶和脲酶活性的 EC50 值均显著降低（p<0.05），这表明它们比其他两种酶更敏感。
