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该文以福建武夷山亚热带常绿阔叶林为研究对象,通过设置3个氮(N)添加梯度的野外实验,研究了群落内乔木植物、灌木植物、草本植物、蕨类植物和苔藓植物叶片N、磷(P)化学计量特征对N沉降的响应,以及不同功能群和物种化学计量特征对N沉降响应的差异。在已开展5年人工N添加的样地内,3年的监测结果表明:N添加整体上提高了植物叶片N含量,草本层植物叶片N含量对N添加的响应比乔木层和灌木层植物更加敏感,优势种米槠(Castanopsis carlesii)、草本植物砂仁(Amomum villosum)、蕨类植物狗脊(Woodwardia japonica)的叶片N含量显著增加。N添加整体上增加了植物叶片P含量,乔木层植物和灌木层植物叶片P含量没有显著变化,草本层植物叶片P含量显著增加,而苔藓植物叶片P含量显著减少。N添加促使武夷山亚热带常绿阔叶林植物叶片N:P由18.67上升至19.72,加剧了植物生长的P限制;乔木物种N:P的变化较灌木和草本物种更加稳定。N添加条件下,植物叶片N:P的变化主要受到叶片P含量而非N含量变化的影响,N添加对生态系统P循环的影响显著。
In this paper, the Wuyi Mountain subtropical evergreen broad-leaved forest in Fujian as the research object, by setting three nitrogen (N) gradient addition field experiments to study the community of arbors, shrubs, herbs, ferns and bryophytes leaves N , The response of phosphorus (P) stoichiometry to N deposition, and the difference of response to N deposition of different functional groups and species stoichiometry. In the 5 years of artificial N addition, the 3-year monitoring results showed that: N addition increased the N content of plant leaves as a whole, and N responses of plant leaves were more sensitive to N addition than those of tree layer and shrub layer , And the N content of leaves of dominant species Castanopsis carlesii, Amomum villosum and Woodwardia japonica increased significantly. N addition increased plant P content as a whole, P content in plant layer and shrub layer did not change significantly, P content in herb layer significantly increased, but P content in bryophyte leaf decreased significantly. N addition led to an increase of N: P from 18.67 to 19.72 in Wuyishan subtropical evergreen broad-leaved forest plants, aggravating the P limitation of plant growth; N: P of arbor species was more stable than shrubs and herbaceous species. Under the N addition condition, the change of N: P in plant leaves was mainly affected by the content of P but not the content of N in leaves, and the effect of N addition on the P cycle of the ecosystem was significant.