菲在黑麦草种植土壤中的降解及其对土壤酶的影响

研究了种植黑麦草对土壤中3环多环芳烃菲的动态降解作用。结果表明,黑麦草可以促进土壤中菲的降解,在75 d的盆栽试验里,种植黑麦草土壤中菲的可提取浓度明显低于不种植土壤（p<0.05）。在菲浓度为5 mg kg^-1、50 mg kg^-1、200 mg kg^-1的3种处理中,种植黑麦草壤中菲的降解率分别为81.07%、90.35%、84.94%,而不种植土壤中菲的降解率分别为75.34%、86.62%、67.60%。种植黑麦草增强了土壤中多酚氧化酶、脱氢酶和过氧化氢酶的活性以及增加土壤中微生物生物量碳的含量,即提高了土壤中生物活性,从而促进了土壤中菲的降解率。不同浓度菲处理,土壤中生物活性存在明显差异,高浓度菲(200 mg kg^-1)对土壤中生物活性产生较强的抑制作用,影响土壤中生物对菲的降解作用,从而揭示了植物促进菲降解的生物学及酶学机理。黑麦草对土壤中多环芳烃有较强的忍耐性,但过高的菲浓度对黑麦草的生长有影响。

Effect of ryegrass plantation on degradation of phenanthrene and enzyme activity in the soil

A 75-day-long pot experiment was carried out to study effect of plantation of ryegrass (Lolium multiflorum) on dynamic degradation of phenanthrene (PHE) in soil. Results indicate that ryegrass plantation enhanced degradation of PHE in the soil, thus making the content of extractable PHE lower (p<0.05) in the ryegrass pots than in CK (pots without ryegrass). In the treatments, 5, 50, and 200 mg kg^-1 in PHE concentration, PHE degradation rate reached 81.07%, 90.35% and 84.94%, respectively, while in CK it was only 73.5%, 86.2% and 67.60%, respectively. Ryegrass plantation enhanced activities of polyphenol oxidase, dehydrogenase and catalase, and increased content of microbiological biomass C, that is, the soil biological activity, thus raising the degradation rate of PHE in the soil. And soil biological activity varied sharply from treatment to treatment. Higher concentration of PHE inhibited soil biological activity, and in turn the effect of soil biology on PHE degradation. Thus, the findings disclose the biological and enzymological mechanisms of the plant enhancing PHE degradation. And it was also found that ryegrass is rather tolerant to polycyclic aromatic hydrocarbons, but higher PHE concentration affected ryegrass growth.