Advances in plant nitrous oxide (N₂O) emissions

Nitrous oxide (N₂O) significantly affects atmospheric environment quality and global climate change. N₂O emissions intensify greenhouse effects and lead to terrestrial reactive nitrogen loss and stratospheric ozone consumption. Soil is considered the primary source of N₂O emissions from terrestrial ecosystems. However, recent studies indicate that plants also contribute to terrestrial ecosystem N₂O emissions. Plant N₂O emissions have been increasingly studied over the last decade, but a review of the N₂O plant emission pathway and regulatory mechanisms is lacking. This paper summarized the traditionally recognized N₂O sources and sinks, and proposed that terrestrial plants may be another unrecognized N₂O source. Two potential plant N₂O emission pathways were analyzed: 1) soil microorganisms produce N₂O which is then emitted by plants or 2) plants produce N₂O 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 N₂O plant emissions. This study suggests that specific plant N₂O production pathways and their contributions to global N₂O emissions should be explored, with a focus on the physiological and biochemical processes of plants and the role of the symbiotic microorganisms in N₂O production.