【作者】 殷士学； 陈丽敏；

【Author】 Yin Shi-xue Chen Li-min(Agronomy Department, Agricultural College, Yangzhou University, Yangzhou 225009)

【机构】 扬州大学农学院；

【摘要】 氮素转化过程主要由微生物参与。自养硝化细菌有对付缺氧或厌氧环境的能力,可以生活在厌氧环境中,有些硝化细菌可以反硝化。异养硝化菌对土壤硝化作用的贡献不及自养菌。自养和异养硝化菌联合硝化是很可能的,联合机理也可能是多样的。许多异养硝化菌可以同时进行反硝化。反硝化细菌主要是兼厌氧和微嗜氧菌,几乎没有专性厌氧菌,厌氧/少氧是反硝化的必要条件。氧分压与气态氮化物组成有关。不同硝酸还原菌有可能相互协作,此菌的还原产物被彼菌用作底物,最终将NO3-还原成N2,起到等同于反硝化菌的功能。有些真菌和细菌能在好气条件下进行反硝化。厌气铵氧化反硝化是由不同的细菌联合作用的结果还是由专门一类菌完成仍不清楚。土壤中DNRA过程大约占硝酸还原量的2.1%~14.2%。通过适当的土壤管理措施可以增强DNRA过程。分子微生物生态学技术日趋成熟,为打开土壤微生物“黑箱”提供了有力的工具。利用这种工具已经使人们对硝化、反硝化的认识有了新的进步。今后拟加强分子微生物生态学技术应用于土壤微生物的研究,尤其是针对土壤中参与氮氧化物还原的微生物多样性的研究。更多还原

【Abstract】 SummarySoil nitrogen transformations are mainly participated by microorganisms. Autotrophic nitrifiers, widely recognized as obligatory aerobes in the past, are now found to be able to live and nitrify in anaerobic environment. Some autotrophic nitrifiers are able to produce nitrogen gases under aerobic conditions. Heterotrophic nitrifiers as a physiological group apparently contribute less to soil nitrification than autotrophic ones. An enhanced nitrification may be expected by the combination of autotrophic and hetreotrophic nitrifiers. Many heterotrophic nitrifiers are also capable of denitrification. Denitrifiers are basically aerobic bacteria. Strict anaerobic condition is not required for their growth, but low oxygen partial pressure or anaerobic environment is required for denitrification. The reduction products vary with oxygen partial pressure. Nitrate reducers, which may or may not be denitrifiers according to the accepted criteria, are diverse in their reduction properties for nitrogen oxide. Successive denitrification may be possible among these nitrate reducers in the way that one’s product serves as another’s substrate. Some fungi as well as bacteria can denitrify under aerobic environment. Whether the "Anammox" , a process found in activated fluid reaction bed, may occur in soils remains to be answered. Dissimilatory nitrate reduction to ammonium (DNRA) may account for 2.1%~14.2% of nitrate reduction in paddy soils under laboratory conditions. Soil management such as continuous straw mulching might help increasing DNRA. Molecular approaches are powerful in revealing the knowledge that is impossible to be known by conventional approaches. This has been demonstrated by publications in related fields. Future attention should be directed to this field.更多还原