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The potentials of three plant species, rape, alfalfa and white clover, separately or jointly in promoting the degradation of Phenanthrene (Phe) and pyrene (Pyr) in soils were studied by pot experiments in a greenhouse.The results showed that the presence of vegetation apparently enhanced the dissipation of PAHs in the soils at their initial concentrations ranging from 20.05~322.06 mg kg-1, but the efficacy varied greatly among plant species and cropping patterns.Alfalfa and white clover showed higher efficiencies for the removal of PAHs.Averagely, about 41.46% of Phe or 33.69% of Pyr were removed from soils after 70-day plantation of alfalfa, and 38.75% of Phe or 36.29% of Pyr removed by white clover, as compared to the much lower degradation rates of 22.57% of Phe or 18.24% of Pyr for the non-planted soil.Mixed cropping significantly enhanced the remediation efficiencies as compared to single cropping;about 74.87% of Phe or 62.81% of Pyr were removed by mixed cropping of rape and alfalfa, and 72.01% of Phe or 68.44% by mixed cropping of rape and white clover.The enhancement effects of PAHs dissipation by plantation mainly attributed to the plant-microbial interaction, while plant uptake and accumulation only accounted for a small part of the total PAHs input.At the same soil concentrations, PAHs concentrations accumulated in plant tissues, irrespective of root and shoot, were much lower in mixed-cropping treatments than those in single-cropping treatments.