环丙沙星对土壤微生物量碳和土壤微生物群落碳代谢多样性的影响

Effects of ciprofloxacin on microbial biomass carbon and carbon metabolism diversity of soil microbial communities

采用氯仿熏蒸浸提法和Biolog法,分析环丙沙星作用下的土壤微生物量碳和微生物群落碳代谢多样性,以揭示环丙沙星在环境中残留对土壤微生物学性状的影响。结果表明,环丙沙星(wCIP≥0.1μg/g)对土壤微生物量碳含量影响显著(P<0.05),土壤中环丙沙星浓度愈高,微生物量碳含量愈低,100μg/g的环丙沙星处理使土壤微生物量碳含量下降58.69%。环丙沙星对土壤微生物群落碳代谢功能影响显著,环丙沙星降低了土壤微生物对碳水化合物、羧酸、氨基酸、聚合物、酚类和胺类的碳源利用率;环丙沙星(wCIP≥0.1μg/g)显著影响了土壤微生物群落碳源代谢强度和代谢多样性,但不同浓度的环丙沙星对土壤微生物群落碳代谢功能的影响不同,0.1、1、10μg/g的环丙沙星处理对土壤微生物群落碳代谢功能的影响主要表现在处理前期(用药第7天、21天),这种影响在处理后期(用药第35天)表现不明显,100μg/g的环丙沙星在用药的前期和后期均显著影响土壤微生物群落碳代谢功能,土壤中环丙沙星积累到该浓度可能对土壤微生物群落碳代谢功能产生难以逆转的长期影响。

To evaluate the effects of ciprofloxacin （CIP） residues on the microbiological characteristics of soil, the microbial biomass carbon （MBC） and carbon-source metabolic functions of the soil microbial communities exposed to CIP were studied by the method of chloroform fumigation extraction and Biolog technology. The results showed that the content of MBC of groups treated with CIP （ WCIP≥ 0. 1 μg/g） were significantly distinguished from that of CK, and they were decreased with the increasing concentration of CIP in soil, the content of MBC in soil exposed to 100μg/g CIP decreased 58.69%. Moreover, the carbon-source metabolic functions of the soil microbial communities exposed to CIP significantly decreased, too. Under the application of CIP, the microbial utilization rate of carbon sources, including carbohydrates,carboxylic acids, amino acids, polymers, phenols, and amines decreased. However, the carbon-source metabolic capacity and diversity of the soil microbial communities exposed to 0. 1μg/g, 1μg/g, 10μg/g and 100μg/g CIP were significantly influenced, in different patterns. I.e. , the carbon-source metabolic functions of the soil microbial communities exposed to 0. 1μg/g, 1μg/g and 10μg/g CIP for 7 and 21-day were significantly lowered but no significant difference found after 35- day exposure to 0. 1μg/g, μg/g and 10μg,/g CIP, while that exposed to 100μg/g CIP for 7, 21, and 35-day were all significantly lowered. It was concluded that a certain accumulation of CIP in soil, for instance, 100lzg/g CIP performed irreversible and long-term effects on the metabolic functions of the soil microbial communities.