植物-菌株联合去除土壤中的芘
Department of Ecological Environment Monitoring,China National Environmental Monitoring Centre，Beijing 100012，China

从山东省胜利油田某油井附近土壤中筛选出对芘具有较强降解能力的菌株P6，测定其和苜蓿联合培养下对芘的降解情况。结果表明：与单独菌株P6降解芘相比，土壤中种植苜蓿后，芘的去除率得到明显提高（20 d时去除率为43.49%）。种植苜蓿后，基质土壤特别是根际土壤中，菌株P6的数量有了较大的提升，且土壤中的过氧化氢酶和多酚氧化酶活性也得到了较大提高。可见，苜蓿除了能吸收芘外，还能通过改善土壤环境，起到强化微生物降解芘的作用。
Pyrene-degrading bacteria along with alfalfa were studied for their potential in removal of pyrene contamination from soil.43.49% of pyrene was degraded by P6- alfalfa association at 20 d.In contrast,23.46% and 15.21% of pyrene was only removed by strain P6 and alfalfa， respectively.It was indicated that the P6- alfalfa association was more effective in removal of pyrene.The pyrene was also both detected in the shoots and roots of alfalfa,and more pyrene was accumulated in the roots than those in the shoots.Through analysis of pathways of pyrene removal，this enhanced removal of pyrene by plant-microbial association might be the result of alfalfa promoted microbial degradation.The POD (peroxidase) in plant roots was higher than that in shoots,and the PPO (phenol oxidase) in roots was lower than that in shoots.The catalase and polyphenol oxidase activities in soil were both higher in planted soil than unplanted soil.And the bacterial populations in soil，especially in rhizosphere were also inspired by the growth of alfalfa.These could be explained by the rhizosphere effect.This enhanced dissipation of pyrene in planted soil might be due to increased biological activity in the rhizosphere.Therefore， bio-removal of pyrene in the contaminated soils was feasible using alfalfa.