黑土微生物丰度和多样性对邻苯二甲酸二丁酯污染的响应

摘要

邻苯二甲酸二丁酯（Di-n-butyl phthalate，DBP）是一种在环境中广泛存在的有机污染物，已被中国环境检测中心和美国环保署列为优先控制污染物。该研究探讨了黑土微生物丰度和多样性对不同浓度DBP（0、5、10、20和40 mg·kg-1）污染的响应。研究结果基本表明，黑土中的细菌、真菌和放线菌的生长（数量）对DBP污染均表现为被抑制效应，且在污染初期抑制效应与DBP浓度呈正相关，随着培养时间的增加有减缓的趋势，但在短期（25 d）内并未完全消除。为了确证这一结果，选择了4种有代表性的微生物，做了进一步的研究。结果同样表明自生固氮菌、亚硝酸氧化菌和磷细菌的生长均受到DBP污染的抑制，且抑制效应与DBP污染浓度呈显著性正相关（P=0.05）；但是铁细菌的生长（数量）却受到了 DBP 污染的促进，且增幅与 DBP 污染浓度呈现正相关。采用 RAPD 方法研究表明，黑土微生物的丰富度和Shannon-Weanier多样性受到DBP污染的抑制，且10、20和40 mg·kg-1的污染浓度处理的抑制效应在25 d内并未完全消除。因此，可以得出结论：DBP 污染改变了黑土微生物区系结构和功能代谢菌群数量，降低了黑土微生物的多样性与丰度，从而有可能影响黑土的生态系统功能，威胁黑土的可持续利用。%Di-n-butyl phthalate (DBP), belonging to the family of phthalic acid esters, is a plasticizer and widely used in the world for many years. Nowadays, it has become a ubiquitous environmental pollutant and listed as an environmental priority pollutant by China's Environmental Monitoring Center and United States Environmental Protection Agency. The purpose of this study is to estimate the responses of the bacterial community, typical functional bacteria and bacterial biodiversity in black soil to DBP (0, 5, 10, 20 and 40 mg·kg-1) contamination. The results showed that the amounts of bacteria, fungi and actinomycetes in black soil were reduced by DBP contaminations, and the inhibitions, which did not disappear within 25 d, were correlated with DBP concentration. To confirm the phenomena, the further studies were performed with nitrogen fixing bacteria, nitrite-oxidizing bacteria, inorganic phosphorus bacteria and iron bacteria, separately. The similar results were obtained. However, as an exception, the growth of iron bacteria were promoted by DBP contamination. The studies, which based on RAPD method, showed DBP contamination decreased the richness and Shannon-Weanier index. Therefore, it could be drawn that DBP could impact the ecosystem functions by affecting the microflora, functional bacteria and biodiversity in black soil, and even threaten the sustainable utilization of black soil for agriculture.