中文摘要：

全球气候变化包括氮沉降增加和降水格局改变,影响着生态系统的生物地球化学循环,进而可能会对植物的养分保持特性产生影响。研究不同氮、磷和水分梯度上植物叶片养分特性的响应格局,对于预测氮沉降增加和降水格局的改变对植物养分策略的潜在影响,具有一定的理论与实践意义。该研究通过3个盆栽控制实验（施氮肥实验：0、0.5、1、2、4、8、16、32、64和128g·m-2等10个水平;施磷肥实验：梯度同施氮肥实验;控水实验：3600、4000、4500、5143、6000、7200、9000、12000、18000和36000ml-pot-1等10个水平）,探讨了羊草（Leymuschinensis）绿叶氮、磷浓度和比叶面积（Specificleafarea,SLA）对这些环境因子改变的响应。结果表明,在一定范围内,施氮肥提高了羊草绿叶比叶面积和绿叶氮浓度,但对绿叶磷浓度没有明显的影响;施磷肥显著提高了绿叶比叶面积、绿叶氮浓度和绿叶磷浓度;供水量增加提高了羊草绿叶比叶面积,降低了绿叶氮浓度,但对绿叶磷浓度无显著影响。这表明,氮、磷和水分因子的改变影响了植物叶片的养分保持能力,且不同梯度的影响程度也不同。因此,全球气候变化可能影响植物养分利用策略,进而可能对植被-土壤系统养分循环产生影响。

英文摘要：

Aims Global climate changes, including changes in atmospheric nitrogen （N） and precipi-tation, have altered biogeochemical cycling in ecosystems and are expected to affect plant nutrient economy. Our objective was to investigate the potential effects of global climate changes on nutrient use strategy of species. Methods We studied leaf-nutrient traits in green leaves of Leymus chinensis in relation to N, phos-phorus （P） and water changes using three pot experiments. The N experiment and the P experiment in-volved additions of 0, 0.5, 1, 2, 4, 8, 16, 32, 64 and 128 g-m-2. The water supply experiment involved additions of 3 600, 4 000, 4 500, 5 143, 6 000, 7 200, 9 000, 12 000, 18 000 and 36 000 ml-pot-1, respectively. Important findings N addition increased specific leaf area （SLA） and N concentration, but did not significantly affect P concentration. In contrast, P addition increased SLA, N concentration and P concentration. Water addition increased SLA, but decreased N concentration and did not affect P concentration. These results suggested that changes in N, P and water availabilities affect green-leaf nutrients, and thus plant nutrient economy and nutrient cycling in the plant-soil ecosystem.