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气孔控制着光合作用和蒸腾作用两个相互耦合的过程,气孔导度与光合速率的耦合关系是理解陆地生态系统碳循环和水循环及其耦合关系的基础。利用LI-6400光合仪控制光强和CO2浓度变化,分析了C3和C4作物气孔导度-光合速率耦合关系的差异。结果表明:即使CO2浓度变化条件下,Ball-Berry模型也能很好地模拟气孔导度与光合速率二者的耦合关系。气孔导度与净光合速率之间的耦合系数体现了不同作物之间水-碳交换比例的差异,反映了气孔限制和内部生理生化过程限制在不同作物上所占的比例。由于该系数在C3作物和C4作物之间存在明显差异,C3作物中,陆生C3作物和水生C3作物也存在一定差异,因此作物的生态功能类型可以大体划分为3类:C4作物、陆生C3作物和水生C3作物。这种生态功能类型的划分为提高碳循环、水循环以及水碳耦合循环模型在区域尺度上应用的精度是有益的。
Stomata control the process of photosynthesis and transpiration of two mutual coupling, stomatal conductance and photosynthetic rate of the coupling relationship is to understand the terrestrial ecosystem carbon cycle and water cycle and the coupling relationship between the foundation. LI-6400 photosynthetic apparatus was used to control the changes of light intensity and CO2 concentration, and the differences of stomatal conductance-photosynthetic rate coupling between C3 and C4 crops were analyzed. The results show that the Ball-Berry model can well simulate the coupling relationship between stomatal conductance and photosynthesis rate under the conditions of CO2 concentration change. The coupling coefficient between stomatal conductance and net photosynthesis rate reflects the difference of water-carbon exchange rate among different crops, and reflects the stomatal limitation and the restriction of internal physiological and biochemical processes on different crops. Because of the significant difference between the C3 crop and the C4 crop, there are also some differences in the C3 crop between the terrestrial C3 crop and the aquatic C3 crop. Therefore, the types of crop ecological functions can be broadly divided into three categories: C4 crops, Terrestrial C3 crops and aquatic C3 crops. The division of this type of ecological function is useful to improve the accuracy of the carbon cycle, water cycle, and water-carbon cycle models applied at the regional scale.