中文关键词土壤厌氧培养硝酸盐反硝化酶活性蒽降解 英文关键词soilanaerobic incubationnitratedenitrification enzyme activityanthracenedegradation

作者	单位	E-mail
代军帅	西南大学资源环境学院, 重庆 400715	735010256@qq.com
左小虎	西南大学资源环境学院, 重庆 400715
王明霞	西南大学资源环境学院, 重庆 400715
姚炎红	西南大学资源环境学院, 重庆 400715
周志峰	西南大学资源环境学院, 重庆 400715	zhouzhf@swu.edu.cn

中文摘要 多环芳烃（polycyclic aromatic hydrocarbons，PAHs）在土壤中的反硝化降解是其厌氧去除的重要途径之一，但严格厌氧条件下反硝化电子受体（硝酸盐）对土壤反硝化活性及PAHs降解影响的报道还不多见.通过添加硝酸盐和蒽的厌氧微宇宙培养实验，探讨厌氧条件下硝酸盐对土壤蒽的厌氧降解及反硝化活性的影响.设置了不添加（N₀）和添加硝酸盐（N₃₀：30 mg·kg^-1）的两组处理，每组处理分别含3个蒽浓度（A₀：0 mg·kg^-1、A₁₅：15 mg·kg^-1、A₃₀：30 mg·kg^-1），共6个处理（N₀A₀、N₀A₁₅、N₀A₃₀、N₃₀A₀、N₃₀A₁₅、N₃₀A₃₀）.厌氧条件下25℃黑暗培养45 d，并于第3、7、15及45 d测定土壤N₂O和CO₂的产生速率、反硝化相关功能基因（narG、nirK、nirS）丰度及蒽含量.结果表明，在培养第3 d检测到较强的反硝化活性，且硝酸盐及蒽均能显著促进土壤的反硝化酶活性.随着培养时间的延续，各处理中土壤反硝化活性急剧下降，蒽对土壤反硝化活性却表现出明显的抑制作用.方差分析的结果也表明，硝酸盐、蒽及其交互作用均能显著影响土壤的反硝化活性.3种反硝化功能基因中，只有 narG和nirS基因的丰度在培养期间呈现逐渐升高的趋势，且它们能够受到硝酸盐、蒽及其交互作用的显著影响.厌氧条件下土壤蒽的最终去除率在33.83%~55.01%之间，添加硝酸盐对土壤蒽的去除率和降解速率均无显著影响，但高蒽含量（N₀A₃₀、N₃₀A₃₀）处理的降解速率显著高于低蒽含量（N₀A₁₅、N₃₀A₁₅）处理（P<0.05）.综上，硝酸盐的添加能显著影响土壤的反硝化活性及与反硝化相关的narG和nirS基因的丰度，但对土壤蒽的厌氧降解无显著影响. 英文摘要 The degradation of soil polycyclic aromatic hydrocarbons (PAHs) under denitrification is one of the most important pathways for anaerobic PAH elimination, but little is known about the effect of nitrate (the terminal electron acceptor for denitrification) on soil denitrification activity and PAH degradation under anaerobic conditions. In this study, the effect of nitrate on soil anthracene anaerobic degradation and denitrification activity was investigated through an anaerobic microcosm experiment. Two groups of treatments without (N₀) and with (N₃₀) nitrate (30 mg·kg^-1) amendment were conducted. Each group contained three treatments with different anthracene concentrations (0, 15, and 30 mg·kg^-1, denoted as A₀, A₁₅, and A₃₀, respectively). Therefore, a total of six treatments (N₀A₀, N₀A₁₅, N₀A₃₀, N₃₀A₀, N₃₀A₁₅, and N₃₀A₃₀) were incubated in darkness at 25℃ for 45 days, and the production rates of N₂O and CO₂, abundances of denitrification related genes (narG:periplasmic nitrate reductase gene; nirK:copper-containing nitrite reductase gene; and nirS:cd₁-nitrite reductase gene), and soil anthracene content were measured at 3, 7, 14, and 45 days. The results indicated that the intensive denitrification enzyme activity in each treatment was only detected at day 3, which could be significantly enhanced by both nitrate and anthracene amendments. Subsequently, a sharp decline of denitrification enzyme activity was observed in each treatment, while anthracene showed an obvious inhibition of soil denitrification enzyme activity. The result of a two-way ANOVA also indicated that nitrate, anthracene, and their interactions had significant effects on soil denitrification enzyme activity. The result of a quantitative-PCR indicated that, during the incubation, the abundances of narG and nirS exhibited an increasing tendency, but the abundance of nirK was relatively constant compared with its former counterparts. The final removal rate of anthracene under anaerobic soil environment was in the range of 33.83%-55.01%, and neither the final removal rate nor the degradation rate of anthracene could be significantly affected by nitrate amendment during incubation. The anthracene degradation rates in the higher anthracene containing treatments (N₀A₃₀ and N₃₀A₃₀) were significantly higher than those in the lower anthracene containing treatments (N₀A₁₅ and N₃₀A₁₅). In summary, nitrate amendments had no effect on soil anthracene anaerobic degradation but could significantly affect soil denitrification enzyme activity and the abundance of denitrification related narG and nirS genes.

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