蚯蚓及蚓粪对白腐真菌降解土壤中菲的动态影响

Effect of Earthworms and Earthworm Casts on The Degradation of Phenanthrene in Artificially Contaminated Soil by White-rot Fungi (P.chrysosporium)

通过接入白腐真菌、蚯蚓和蚓粪,研究了通过蚯蚓及蚓粪的作用来改善土壤环境,从而提高土壤原位生物修复的可行性。结果显示,在30d的黑暗培养试验里,土壤中菲浓度随着时间逐渐减少,蚓粪和蚯蚓自身均能促进土壤中菲的降解,但蚓粪的促进作用要优于蚯蚓的作用;在100mg·kg-1菲处理浓度下,蚓粪处理中菲残留浓度在培养的第4d显著低于其他处理。试验结果还表明,在加入白腐真菌的土壤中,蚓粪和蚯蚓都能促进白腐真菌对菲的降解,且显著高于只接入白腐真菌的处理。同时加入蚯蚓和白腐真菌的处理中木质素过氧化物酶(LiP)和锰过氧化物酶(MnP)酶活性虽然在一直下降,但蚯蚓的加入减缓了酶活性的下降趋势,从而使得蚯蚓提高了处理中白腐真菌对菲的降解率。而同时加入蚓粪和白腐真菌的处理中的LiP和MnP酶活性变化则要相对复杂,在培养前、中期,两种酶的活性分别表现出不同的变化趋势,而在培养后期,两种酶的活性均显著增高。因此,同时加入蚓粪和白腐真菌处理的菲浓度在培养后期才与只加入白腐真菌的处理产生显著差异。结果表明,蚓粪和蚯蚓可能是通过改善土壤环境条件、促进微生物活性、增强土壤中过氧化物酶活性来提高白腐真菌对菲的降解率。但是,其中的作用机制需要进一步试验证实。

Through dark incubation with white-rot fungi, earthworms and earthworm casts, the study was to discuss the feasibility of in-situ bioremediation of contaminated soil by earthworms and earthworm casts. The results showed that the concentration of phenanthrene in soil gradually reduced and the effect of earthworm casts was significantly superior to that of earthworms. Average removal of phenanthrene by earthworm casts alone was significantly higher than that by other treatments at the forth day. In the treatments added with white-rot fungi, both earthworm casts and earthworms could stimulate the degrading effect of white-rot fungi on phenanthrene in soil. Although the activities of LiP and MnP in treatment with white-rot fungi and earthworms reduced, the earthworms slowed down the reduction of enzyme activities, which stimulated the degradation of phenanthrene by white-rot fungi. Compared with earthworms, the treatment added with both earthworm casts and white-rot fungi showed more complicated changes of enzyme activities. During most time of incubation, two enzyme activities changed differently. But at the end of incubation, both of the two enzyme activities were significantly promoted. So phenanthrene concentration of this treatment was significantly different with the treatment only added with white-rot fungi at the end of incubation. The results indi cated that earthworm casts and earthworms might stimulate the effect Qf white-rot fungi by enhancing the enzyme activities. However, the mechanism might need further experiments.