【摘要】 北方森林是全球第二大生物群区,约占全球森林面积的30%,尽管其细根生物量仅占森林生态系统很小的一部分,但其周转率更快,更易分解,因此,其对土壤碳循环和大气CO₂通量贡献很大。笔者综述了氮沉降和CO₂浓度升高的背景数据,总结了细根对二者变化的响应,主要从细根的形态特征、解剖结构和生理功能方面入手,探讨了其对氮沉降和CO₂浓度升高的响应。结论如下:（1）大气氮沉降量一直处于上升状态,与人类活动密切相关的有机氮量所占比例逐渐加大,而无机氮中NH₄^-N和NO₃^-N的变化趋势表现不同;（2）大气CO₂浓度一直呈上升趋势,细根形态特征、解剖结构和生理功能对其表现出明显的响应;（3）树种、年龄、土壤类型等都会改变细根形态、解剖结构和生理功能对氮沉降和CO₂浓度升高的响应结果,但改变的程度不同。研究结果可为北方森林乃至温带森林生态系统功能对氮沉降和CO₂浓度升高的响应提供参考依据和数据支持。更多还原

【Abstract】 Boreal forest is the second largest biome in the world, accounting for about 30 percent of the globalforest area. Although fine root biomass accounts for only a small fraction of the total in boreal forest, theirturnover rates are faster and can be more easily decomposed, so they contribute more to soil carbon cycle andatmospheric CO₂ flux. In this paper, the authors summarized the background data of nitrogen（N） depositionand CO₂ concentration and the response of fine root to them from the aspects of the morphology, anatomicalstructure and physiological function. The results are as follows:（1） atmospheric N deposition is in a risingcondition, and the proportion of organic N which is closely related to human activities gradually increased,while the trends of NH₄^-N and NO₃^-N in inorganic nitrogen are different;（2） atmospheric CO₂ concentration isalso in a rising trend, the fine root morphological characteristics, anatomical structure and physiologicalfunction show obvious response to it;（3） tree species, age, soil types all affect the fine root morphology,anatomical structure and physiological functions and its response to nitrogen deposition and CO₂ concentration,but the change degrees are different. The results could provide reference basis and data support for theresponse of boreal forest and temperate forest ecosystem function to nitrogen deposition and elevated CO₂ concentration.更多还原