氮磷肥料对HB-5菌株降解莠去津的促进作用及去毒效应的影响

以莠去津降解细菌HB-5为研究对象,进行了氮、磷肥单一及复合施肥对HB-5细菌降解土壤中莠去津的促进作用的研究,探讨了莠去津降解率与土壤中速效氮、速效磷含量之间的关系及莠去津降解过程中生态毒性的变化情况.莠去津在土壤中的残留采用高效液相色谱法进行测定;土壤中速效氮和速效磷分别采用碱解扩散法及0.5mol/L-NaHCO3浸提-钼锑抗比色法测定;土壤的生态毒性采用蚕豆根尖微核法进行测定.结果表明,在实验的前5d,不论氮、磷肥单一或复合施肥均能够明显促进HB-5对莠去津的降解,不同施肥条件下莠去津的降解速率依次为:氮、磷肥复合单施磷肥单施氮肥不施肥料对照;实验5d后,各处理中莠去津降解率没有显著差异(p0.05),均达到了95%以上.土壤中速效氮和速效磷含量随着莠去津的降解而呈现逐渐减少的趋势.土壤的生态毒性试验结果表明,莠去津经HB-5菌株降解后,土壤的生态毒性显著降低;各施肥处理土壤中莠去津的生态毒性均低于不施肥处理的土壤;实验的前5d,各处理土壤中生态毒性的大小依次为:氮、磷肥复合单施磷肥单施氮肥不施肥料对照.实验7d时,各处理土壤中莠去津的生态毒性均恢复到空白对照水平.氮磷肥料的施用不仅能促进HB-5菌株对土壤中莠去津的降解,而且能加速降低土壤的生态毒性,为莠去津污染土壤的快速修复提供了理论依据.

Effects of Nitrogen and Phosphorus Fertilizer on Atrazine Degradation and Detoxification by Degrading Strain HB-5

An atrazine-degrading strain HB-5 was used as a bacteria for biodegradation. Treatments of soil with nitrogen single, phosphate single and nitrogen phosphate together with HB-5 were carried out for degradation and eco-toxicity test; then, relationship between atrazine degradation rate and soil available nitrogen, available phosphorus were discussed. Atrazine residues were determined by HPLC; available nitrogen was determined with alkaline hydrolysis diffusion method; available phosphorus was determined with 0.5 mol/L-NaHCO₃ extraction and molybdenum stibium anti-color method, and toxicity test was carried out with micronucleus test of Vicia faba root tip cells. The results showed that: After separately or together application, nitrogenous and phosphorous fertilizers could significantly accelerate atrazine degradation than soil with HB-5 only. On day 5, the order of atrazine degradation was ANP> AP > AN >A; 7 days later, no statistically significant differences were found between treatments. The available nitrogen and phosphorus level in soil reduced as the degradation rate increased in the soil. The soil of eco-toxicity test results indicated that the eco-toxicity significantly reduced with the degradation of atrazine by HB-5, and the eco-toxicity on treatments of soil with fertilizer were all below the treatments without fertilizer. On day 5, the order of eco-toxicity was ANP< AP