Effects of Hg on soil enzyme | 汞对土壤酶活性的影响

chinois. 研究Hg对不同土壤酶活性的影响，探讨其中对Hg敏感的酶类，为土壤重金属污染的监测评价及修复等提供依据。通过室内模拟试验，以催化C、N、P、S等循环的土壤酶为对象，较为系统地探讨了3种土壤类型（红壤、褐土、风沙土）6个土样在不同含量Hg下的土壤酶效应。不同土壤酶类受Hg影响的规律有明显差异，1、2、4号土样转化酶活性在Hg含量较低时（0.5 mg/kg）有所升高；随着Hg含量的增加，土壤转化酶、脲酶、脱氢酶、芳基硫酸酯酶和磷酸酶均受到不同程度的抑制。上述5种酶活性及总体酶活性与Hg含量间呈显著或极显著负相关，说明它们在一定程度上可表征土壤的Hg污染程度。供试土壤Hg轻度污染的生态剂量（ED10）为0.03 mg/kg。Hg对绝大多数酶活性表现出完全抑制作用（包括竞争性抑制和非竞争性抑制）。脱氢酶受Hg的抑制程度较大，表明其对Hg较为敏感，因此其可作为Hg污染的监测指标。

anglais. The effect of mercury on the activity of different soil enzyme was studied to provide the monitoring and repair basis for heavy metal contamination of soil. By laboratory simulation experiments, we explored some key enzyme activities which can catalyse C, N, P, S cycles influenced by Hg in six soil samples of three soil types(Red soil, Cinnamon, Sandy soil). The results showed that there are obvious different relationships between enzyme activity and Hg. The invertase activity of 1, 2, 4 soil samples increased with low concentration (0.5 mg/kg ), but with the Hg content increased, the soil invertase, urease, dehydrogenase, arylsulfatase and phosphatase were inhibited to different degrees. The five kinds of enzyme activity and total enzyme activity reached significant or remarkably significant negative correlation with Hg content, revealing to some extent that they could be indexes to monitor soil Hg pollution; the Hg critical content (ED10) was 0.03 mg/kg when the soils were slightly polluted by Hg. The reaction mechanism were fully inhibited (including competitive inhibition and non-competitive inhibition) for most soil enzymes activity. Dehydrogenase was more inhibited by Hg and more sensitive to Hg, so it can be monitoring indicators for Hg pollution.