研究旱地红壤反硝化微生物功能基因nirS、nirK、nosZ I和nosZ Ⅱ 的丰度对温度和氮添加的响应，可为农田红壤养分管理和生态环境保护提供指导和建议。本研究以长期常规氮磷钾施肥的旱地红壤为研究对象，设置3个氮添加(N 0、25、50 mg/kg)处理和3个温度处理(15、25、35 ℃)进行微宇宙培养试验，在培养的7和30 d后破坏性采集土样，进行土壤DNA提取，测定反硝化微生物功能基因丰度。结果表明：培养7 d后，nirS、nirK、nosZ I和nosZ Ⅱ 基因丰度均在25 ℃ 时最高；培养30 d后，nirS、nirK、nosZ I和nosZ Ⅱ 基因丰度在15 ℃ 时最高，且随着温度升高而下降。氮添加对反硝化微生物功能基因丰度无显著影响。3因素方差分析表明，温度、氮添加和培养时间的交互作用显著影响反硝化微生物功能基因丰度。综上，旱地农田反硝化功能基因丰度受氮添加影响较小，但受温度显著影响，其丰度可能会呈现出日变化和季节变化，在土壤采样和氧化亚氮动态监测时应特别注意。

Investigating how the abundance of denitrifying functional genes nirS, nirK, nosZ I and nosZ II respond to temperature and nitrogen addition in upland Ultisol can provide guidance for agricultural nutrient management and environmental protection in this region. In this study, soils were sampled from a long-term fertilization experiment and used for a microcosm incubation experiment under the conditions of three nitrogen addition treatments: N 0, 25, and 50 mg/kg, and three temperature levels at 15, 25, and 35 °C. Soils were incubated in the dark and destructively sampled on days 7 and 30 of incubation. After sampling, soil DNA was extracted, and the abundances of denitrifying functional genes were determined by real-time quantitative PCR. Results showed that the abundances of nirS, nirK, nosZ I and nosZ II genes were the highest at 25 ℃ after 7-day incubation. However, after 30-day incubation, the abundances of nirS, nirK, nosZ I and nosZ II genes were the highest at 15 ℃ and were decreased with increasing temperature. Moreover, nitrogen addition had no significant effect on the abundances of all the denitrifying functional genes. In addition, three-way ANOVA showed that the interactions of temperature, nitrogen addition and incubation time significantly influenced the abundances of denitrifying functional genes. Overall, the abundances of denitrifying functional genes are substantially influenced by temperature but less affected by the nitrogen addition. The abundances of denitrifying functional genes may vary considerably on both a daily and seasonal basis, and this should be taken into consideration during soil sampling and nitrous oxide emission measuring.

S154.36

国家自然科学基金项目(41930756， 42077041)和福建省自然科学基金项目(2020J01187)