Abstract:
Nitrous oxide (N
2O) significantly affects atmospheric environment quality and global climate change. N
2O emissions intensify greenhouse effects and lead to terrestrial reactive nitrogen loss and stratospheric ozone consumption. Soil is considered the primary source of N
2O emissions from terrestrial ecosystems. However, recent studies indicate that plants also contribute to terrestrial ecosystem N
2O emissions. Plant N
2O emissions have been increasingly studied over the last decade, but a review of the N
2O plant emission pathway and regulatory mechanisms is lacking. This paper summarized the traditionally recognized N
2O sources and sinks, and proposed that terrestrial plants may be another unrecognized N
2O source. Two potential plant N
2O emission pathways were analyzed: 1) soil microorganisms produce N
2O which is then emitted by plants or 2) plants produce N
2O via metabolism or the action of endophytes. Subsequently, key factors were analyzed (e.g., nutrients, light, temperature, plant organs, and growth stage) to determine the effects on and mechanisms of N
2O plant emissions. This study suggests that specific plant N
2O production pathways and their contributions to global N
2O emissions should be explored, with a focus on the physiological and biochemical processes of plants and the role of the symbiotic microorganisms in N
2O production.