真菌反硝化过程及其驱动的N2O产生机制研究进展

真菌反硝化过程的发现打破了反硝化过程只发生在原核生物中的传统认识,是对全球微生物氮循环过程的重要补充。真菌参与的反硝化过程由于缺乏N_2O还原酶,其终产物为具有强辐射效应的温室气体N_2O。真菌在环境中分布广泛,生物量巨大,故真菌反硝化作用对全球N_2O释放通量的贡献是不容忽视的。近年来许多研究表明,真菌反硝化过程是自然环境中N_2O产生的重要途径。本文对反硝化真菌的发现、多样性及分布、产生N_2O的机制和活性测定方法等几个方面进行综述,并对未来的研究提出展望。

The diversity distribution and N2O production driven by fungal denitrification in different natural ecosystems

Nitrous oxide (N₂O) is a potent greenhouse gas which generates approximately 300-fold powerful greenhouse effect than carbon dioxide (CO₂) and is one of the main compounds that causing ozone-depletion in stratospheric. Nitrification and denitrification of microorganism is the most important path for N₂O production. It has long been considered that denitrification only occurred in prokaryote until in 1970''s two Japanese scientists found that fungi like Fusarium oxysporum also had the ability to denitrifying. Unlike bacterial denitrification (bDNF), N₂O is the end-product of fungal denitrification process (fDNF) due to the lack of nitrous oxide reductase (nosZ). It means that fDNF usually produce more N₂O than bDNF. Recent studies have proved that fDNF contributed over 50% of the total N₂O emission in soil and 70% in high permeable sediments thus it shouldn''t be neglect. In this review, we elucidated the species composition, denitrification mechanism, measurements and N₂O-contribution of fDNF base on the current studies. At last, we discussed some problems remain to be solved on the research of fDNF and suggest prospects for future studies.