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自然生态系统中的厌氧氨氧化过程是新发现的氮循环途径,已有研究表明水稻土能产生厌氧氨氧化作用,然而目前还鲜有关于水稻土厌氧氨氧化活性测定方法的报道。15N示踪法是定量厌氧氨氧化活性的新方法,根据厌氧氨氧化和反硝化过程原理的不同,该方法可以同时测定厌氧氨氧化和反硝化产生的氮气。本文详细介绍了一种利用稳定同位素标记配对法,通过预培养消耗底物硝酸根后,对反应体系进行三种处理:1)仅加15N-NH4+的阴性对照;2)加15N-NH4+和14N-NO3-的阳性对照;3)仅加15N-NO3-。厌氧培养后分别对三种处理产生的氮气采用稳定同位素质谱仪进行测定,通过数据分析获得厌氧氨氧化活性。本研究建立了水稻土厌氧氨氧化活性测定方法,能较为真实的反应原位条件下水稻土的厌氧氨氧化活性。
Anaerobic ammonium oxidation in natural ecosystems is a newly discovered pathway for nitrogen cycling. Studies have shown that anaerobic ammonium oxidation can occur in paddy soils. However, there are few reports on the anaerobic ammonium oxidation of paddy soils. The 15N tracer method is a new method to quantify the anaerobic ammonium oxidation activity. According to the principle of the anaerobic ammonium oxidation and denitrification process, this method can simultaneously determine the nitrogen produced by anaerobic ammonium oxidation and denitrification. This article describes in detail a stable isotope-labeled pairing method, which pretreated the nitrate substrate and consumed three treatments of the reaction system: 1) a negative control containing only 15N-NH4 +; and 2) a 15N-NH4 + and 14N -NO3- positive control; 3) only plus 15N-NO3-. After anaerobic culture, the nitrogen produced by the three treatments was determined by stable isotope mass spectrometer, and the anammox activity was obtained by data analysis. This study established a method for the determination of anaerobic ammonium oxidation in paddy soil, which can reflect the anammox activity of paddy soil under in situ conditions.