中文摘要：

为探讨苔原植被对气候变暖的响应模式，采用开项箱增温法，研究了3个生长季增温对长白山苔原3种代表植物——牛皮杜鹃（Rhododendron aureum）、笃斯越桔（Vaccinium uliginosum）和东亚仙女木（Dryasoctopetala var．asiatica）的叶片及土壤碳（C）、氮州）、磷（P）含量及其比值的影响。结果表明：增温使土壤N和P的含量分别增加5．88％和4．83％，C含量降低13．19％；增温和对照r不增温）条件下，植物叶片的C、N、P含量及其比值在生长季有明显的变化。增温使笃斯越桔和东亚仙女木叶片的P含量分别增加10．34％和12．87％，牛皮杜鹃则降低了16．26％，增温并没有明显改变3种植物叶片的C、N含量，但牛皮杜鹃和东亚仙女木叶片的C：N值在增温条件下呈现增加趋势。增温使土壤可利用的N、P含量增加。增温对3种植物的C：N值，牛皮杜鹃、笃斯越桔的P含量，以及东亚仙女木的C：P值都产生了显著的影响。结果表明增温增加了长白山苔原P元素对植物生长的限制，且3种植物叶片的C、N、P化学计量学特性对增温的响应模式和尺度没有表现出一致性。

英文摘要：

Aims Our objective was to investigate how warming affected C, N and P contents and C： N： P ratios in leaves of dominant tundra plants in Changbai Mountain.Methods Open-top chambers （OTCs） were used to raise the air and soil temperature in the Changbai Mountain tundra. Eight hexagon OTCs were established according to the standard of International Tundra Experiment （ITEX）. The C, N and P contents and C：N：P ratios in soils and leaves ofDryas octopetala vat. asiatica, Vaccinium uliginosum, Rhododendron aureum were measured during growing season （July to September）. Impormntfindings Wanning increased the soil N and P contents by 5.88% and 4.83%, respectively, but reduced the C content by 13.19%. The contents of C, N and P in leaves showed significant variations for plants in both OTCs and control plots during growing season. The P content in V. uliginosum, R. aureum was increased by 10.34% and 12.87%, respectively, but decreased by 16.26% in D. octopetala ,car. asiatica, by warming. The C：N ratio in leaves ofD. octopetala var. asiatica and R. aureum grown in OTCs showed an increasing trend. Warming resulted in increases in soil available N and P. The ratio of C：N in the three plants, the P content in R. aureum and V. uliginosum, and the ratio of C：P in D. octopetala var. asiatica were significantly affected by warming. The results indicate that wanning would increase the P limitation to plant growth in this area. The pattern and magnitude of leaf stoichiometry of the three tundra plant species respond differently to warming in Changbai Mountain.