大豆N_2O释放与光照度和光合作用的关系

N_2O Emission from Soybean in Relation to Light Density and Photosynthesis

采用分隔式封闭箱法,测定盆栽大豆植株氧化亚氮(N2O)通量以及光照度、光合速率和气孔导度的日变化。同时,观测田间大豆—土壤系统在主要生长阶段N2O释放的变化。在温室里,大豆植株N2O释放在上午10:00时出现一个高峰;中午时N2O释放量较低,此时光照度和光合速率都保持在较高的水平上;在14:00时,N2O释放量达到低谷,光照度达到最大,但光合速率却处于很低的水平;在15:00时,植株N2O的释放达到第二个高峰,但光照度和光合速率却处于快速下降期。结果表明:植物N2O的释放不仅与光合作用的光反应有关,而且也与暗反应有关。上午10:00以后植株N2O释放通量与气孔导度变化没有一致的关系。在大豆生长季,大豆—土壤系统N2O释放通量有两个高峰,第一个峰出现在6月中下旬,第二个高峰出现在9月下旬。

Using the separate closed chamber method, the experiment determined the diurnal change of N2O flux from potted soybean plants, The experiment also measured the diurnal changes of photosynthesis rate and stomatal conductance of the potted plants and light density. In addition, seasonal change of N2O emission from soybean-soil system was observed during the main growth period of soybean, In the greenhouse, N2O emission from soybean plants reached the first peak at 10：00; at morning, N2O emission was at very lower level, while the light density and photosynthesis rate maintained at the high level; at 14：00, N2O emission declined to the bottom and light density reached the peak, but photosynthesis rate was quite lower; at 15：00, N20 release from soybean plants rose to the second peak, while light density and photosynthesis rate decreased sharply. The results showed that N2O releasing from soybean plants has a close relationship with light density and light reaction and dark reaction of photosynthesis.