沼泽湿地生态系统呼吸与温度、氮素及植物生长的相互关系

沼泽湿地生态系统呼吸排放CO₂通量同时受温度、营养元素（N）和植物生长状况的共同影响和相互制约.通过对三江平原沼泽湿地小叶章（Doyeuxia angustifolia）草甸研究发现，CO₂排放通量与温度、氮素和植物生长状况（主要是株高、叶面积和生物量）均存在一定的非线性正相关的关系.其中，生态系统呼吸与温度的变化符合Arrhenius方程.整个生长季生态系统呼吸平均通量与氮输入水平存在指数相关的关系； 与植物体氮含量符合2次函数的关系；与生物量存在对数相关关系；与不同时期的株高均存在较显著的线性相关关系.不同水平的氮输入后，生态系统呼吸与对照处理比较分别升高了20％，42％和142％；生物量分别增大了26％，44％和375％；叶片和植株的氮含量均发生了相应地变化.

Relationship of Ecosystem Respiration with Temperature, Nitrogen and Plant in Freshwater Marshes

The ecosystem respiration was constrained by temperature,nutrient(particularly N) availability and plant growing-status in freshwater marshes.Studying the ecosystem respiration CO_2 from the freshwater marshes in situ in Sanjiang Plain of northeast China,we found that there is the non-linear positive correlation between the ecosystem respiration and the temperature,as well as the N rates and plant growing-status(mainly the plant height,leaf area and biomass).The relationship between the ecosystem respiration and the temperature can be fitted by the Arrhenius function.There was an exponential relationship between the seasonal average respiration and the nitrogen rates,and a quadratic polynomial relationship between the respiration and the N content of the plant,while a logarithmic relationship between the ecosystem respiration and the above-ground biomass.The ecosystem respiration is significantly positive depended on the plant height of the different period.During the whole growing season the mean respiration was increased by 20%,42%and 142%,the above-ground biomass increased by 26%,44%and 375%,respectively,compared to the control,the leaf N content also changed after the nitrogen fertilization,as well as the plant N content.