改性蒙脱石修复镉污染对水稻根际土壤酶活性的影响

为探讨钝化修复重金属Cd污染土壤中改性蒙脱石的使用对水稻根际与非根际土壤Cd活性、酶活性等的影响，采用盆栽试验通过袋式根际箱装置种植水稻，并对土壤施加巯基-蒙脱石复合材料、蒙脱复合调理剂材料及巯基复合材料。结果表明：3种材料以0.5%的量施入后，糙米Cd浓度分别降低43.6%、25.9%和36.0%；Cd有效态浓度在根际土壤中分别降低55.3%、12.0%和35.2%，在非根际土壤中分别降低54.9%、9.76%和35.4%。蒙脱复合调理剂材料能提高土壤中过氧化氢酶、脲酶活性，巯基复合材料能提高土壤中脲酶活性，巯基-蒙脱石复合材料能提高非根际土壤中蔗糖酶活性。施加修复材料后，水稻根际土壤磷酸酶活性显著高于非根际土壤。研究表明，这3种改性蒙脱石钝化材料降低了Cd在根际土壤中的活性，有效地固定了土壤中的Cd，降低了水稻对镉的吸收，同时提高了土壤酶的活性，改善了Cd污染的水稻根际土壤环境质量。

Effects of functionalized montmorillonite on rhizospheric enzyme activities in Cd contaminated soil

In order to clarify the effect of functionalized montmorillonite on the activity of Cd and rhizospheric enzyme activities in Cd contaminated paddy soil, pot experiments were conducted in the rhizosphere of rice with different application amounts of thiol-functionalized montmorillonite, montmorillonite complex conditioner and thiol-functionalized mixed material. Results showed that:when the addition dose of the functionalized montmorillonite respectively at 0.5%, comparing with the control, the cadmium content of the brown rice reduced 43.6%, 25.9%, 36.0%, the available cadmium content in the rhizosphere of rice reduced 55.3%, 12.0%, 35.2%, and the available cadmium content in the non-rhizosphere soil reduced 54.9%, 9.76%, 35.4%, respectively. The treatment of montmorillonite complex conditioner increased soil catalase and urease, the treatment of thiol-functionalized mixed material increased soil urease, and the treatment of thiol-functionalized montmorillonite increased soil sucrose. After Cd contaminated soil being added functionalized montmorillonite, the activity of phosphatase in rhizosphere of rice was significantly higher than that of non-rhizosphere soil. Hence, these materials reduced the activity of Cd in the soil and inhibited the uptake and accumulation of Cd by rice. At the same time, the activities of soil enzyme was increased. Accordingly, the soil environmental quality of Cd polluted rice rhizosphere was improved.