Phytoremediation combined with microbial remediation is a relatively low cost and highly efficient new remediation method for soils moderately contaminated with persistent organic pollutants. Application of new biological resources will promote the further development of this method. In the present study a fungus (Trichoderma reesei FS10-C), a bacterium (Rhizobium meliloti) and alfalfa (Medicago sativaL.) were studied in a pot experiment. There were control pots with inoculation with only inactiveT. reeseiandR.meliloti (CK) and three treatments comprising alfalfa with inactiveT. reeseiandR.meliloti (A), alfalfa inoculated withT. reesei (TA), and alfalfa inoculated withT. reeseiandR. meliloti (TRA). The study was conducted to examine the effects of inoculation withT. reesei andR. melilotion phytoremediation by alfalfof soil contaminated with polycyclic aromatic hydrocarbons (PAHs). The biomass of alfalfa increased by 5.9 and 11.2% in TA and TRA treatments, respectively, after 60 days. The PAH concentrations in A, TA and TRA treatments were significantly (p<0.05) reduced by 17.0, 25.6 and 32.9%, respectively, and only by 5.7% in the control. In addition, inoculation withT. reesei andR. melilotigave higher remove rates of high molecular weight PAHs. The removal efficiencies of 4- and 5(+6)-ring PAHs were18.1 and 24.7%, 21.4 and 28.3%, and 21.3 and 30.1% for A, TA and TRA treatments, respectively. Moreover, the treatments with alfalfa (A, TA, TRA) significantly (p<0.05) increased the soil microbial activity. Compared with the control, soil dehydrogenase activity in A, TA, and TRA treatments increased by 33.2, 34.6 and 32.6%, and the AWCD values and diversity indices were significantly (p<0.05) higher than in the control. The combination of the microorganisms (T. reesei andR. meliloti) with alfalfa therefore stimulated the remediation efficiency of the PAHs by the rhizosphere microflora. This combination might be a promising bioremediation strategy for aged PAH-contaminated soils in the future.%微生物-植物联合修复技术作为一种低耗高效的新型修复手段已经被广泛应用于有机污染土壤的修复领域并取得了较好的效果，新型生物资源的应用将推动该方法的进一步发展。本研究采用温室盆栽实验，以里氏木霉（Trichodermaressei FS10-C）、根瘤菌（Rhizobium meliloti）和紫花苜蓿（Medicago sativaL.）作为供试生物，设置添加灭活菌剂-无紫花苜蓿（CK）、添加灭活菌剂-种植紫花苜蓿（A）、接种木霉菌剂-种植紫花苜蓿（TA）、接种木霉菌根瘤菌复合菌剂-种植紫花苜蓿（TRA）4种处理，探究微生物-植物联合修复对多环芳烃（PAHs）污染土壤的生物修复效果及其微生态效应。结果表明，经过60 d的培养，微生物不仅促进了紫花苜蓿的生长，而且在紫花苜蓿的协同作用下进一步提高了土壤中PAHs降解率。TA处理中紫花苜蓿生物量增加了5.88%，而TRA处理进一步促进了紫花苜蓿的生长，其生物量增加了11.15%；A、TA和TRA处理下土壤中PAHs的降解率分别为17.02%、25.62%、32.93%，显著（p<0.05）高于处理CK（5.67%）。此外，接种菌剂处理（TA、TRA）对土壤中高分子量PAHs具有更好的降解效果，A处理土壤中4-、5（+6）环PAHs的降解率分别为18.13%、24.74%， TA处理为21.41%、28.34%，而TRA处理则为21.29%、30.11%。同时，紫花苜蓿能够通过其根际效应显著促进土壤微生物活性，相较于CK处理，A、TA、TRA处理土壤脱氢酶活性分别提高了33.20%、34.58%、32.65%，A、TA、TRA处理AWCD值和微生物群落多样性指数均显著（p<0.05）高于CK。通过木霉、根瘤菌与紫花苜蓿联合作用不仅可以有效地降解土壤中的PAHs，而且能够恢复土壤微生物生态功能多样性和稳定性。因此，该方法是一种极具潜力的生物修复手段，具有广阔的市场应用前景。
展开▼
