一种新的植物N2O释放光调节模式

植物释放N2O可能是大气N2O的重要来源。植物N2O释放与体内的NO3-还原过程有关,并且受光照强度的调节。较低光强有利于植物产生N2O。作者根据自己的研究结果和他人的工作,提出一个新的N2O释放与光合作用光反应和CO2同化作用关系以及呼吸作用关系的模式。在非光合作用器官,NO3-还原所需要的还原力和碳架来自呼吸作用,而在光合器官则主要来自光合作用。在光合器官中,N2O产生于NO3-还原和NO2-还原过程。硝酸还原对光合作用的CO2同化既有依赖关系,又有竞争关系。当光照较弱时,光合作用提供的还原力不足,对NO2-还原的抑制大于NO3-还原,因此有利于NO2的产生。

A New Model of Light Regulation for N2O Emission from Plants

This paper presents N_2O emission from plants and its light regulation mechanism.Evidences show that plants are possibly an important source of N_2O of atmosphere.N_2O emission is related to nitrate reduction,and regulated by light intensity.Lower light intensity promotes N_2O emission.This paper proposes a relationship pattern of N_2O production with light reaction and CO_2 assimilation of photosynthesis,and with respiration,based on the studies of the authors and other researchers.In non-photosynthetic organs, the reduction power and carbon frame for nitrate reduction come from respiration,whereas in photosynthetic organs,they come from photosynthesis.In photosynthetic organs,N_2O is produced during the processes of NO~-_3 reduction and NO~-_2 reduction.Nitrate reduction depends on carbon frame from CO_2 assimilation and reduction power from light reaction and it competes with CO_2 assimilation.When light intensity is weak,photosynthesis does not provide enough reduction power for nitrate reduction.NO~-_2 reduction is inhibited more seriously than NO~-_3 reduction.As a result,weak light promotes N_2O production.