【摘要】 为了探讨荒漠草原植物养分回收特征对长期增温和氮素添加的响应以及自然降水变异对其的调控作用,该研究依托实施12年的模拟增温和氮素添加实验平台,在相对多雨的2016年（超过长期均值52%）和相对少雨的2017年（低于长期均值16%）,以常见C₃植物银灰旋花（Convolvulus ammannii）和C₄植物木地肤（Kochia prostrata）为研究对象,测定分析绿叶和枯叶的氮磷含量及回收效率。结果表明:（1）在相对多雨年（2016年）,增温使2种植物的绿叶氮、枯叶氮、绿叶磷、枯叶磷含量分别增加了14.32%、25.45%、17.97%和46.47%,氮、磷回收效率分别显著减小了9.41%和16.99%（P<0.05）;氮素添加使2种植物的绿叶氮、枯叶氮、绿叶磷、枯叶磷含量分别提高了17.32%、25.62%、20.21%和51.41%,而氮、磷回收效率显著降低了9.33%和18.89%（P<0.05）;增温+氮素添加共同处理显著增加了植物氮磷含量、降低了氮磷回收效率。（2）在相对少雨年（2017年）,增温、氮素添加、增温+氮素添加处理对植物叶片氮磷含量、回收效率均无显著影响。（3）叶片氮磷含量在物种间差异极显著（P<0.000 1）,而氮磷回收效率在物种间无显著差异。（4）回归分析表明,植物叶片氮磷含量随着土壤无机氮、有效磷及含水量的增加而增加,植物氮磷回收效率则随着土壤养分和水分的可利用性的增加而降低。研究认为,荒漠草原植物养分回收对全球变化的响应受自然降水变异的调控。更多还原

【Abstract】 Based on a 12-year simulated warming and nitrogen（N）addition experiment, we explored the effects of warming and N addition on nutrient resorption for two common species, C₃ plant Convolvulus ammannii and C₄ plant Kochia prostrata, in 2016 with 52% above the long-term mean precipitation and in 2017 with 16% below the long-term mean. Plant N and phosphorus（P）contents, and resorption efficiencies were measured and analyzed. The results showed that:（1） in the wet year（2016）, warming led to increases of 14.32% in green leaf N, 25.45% in senesced leaf N, 17.97% in green leaf P, 46.47% in senesced leaf P, and the N and P resorption efficiency significantly decreased by 9.41% and 16.99%（P < 0.05）. N addition enhanced N contents in green and senesced leaves by 17.32% and 25.62%, and P contents in green and senesced leaves by 20.21% and 51.41%, but it significantly reduced N and P resorption efficiency by 9.33% and 18.89%（P < 0.05）. Combined warming and N addition increased leaf N and P contents, and decreased resorption efficiency.（2） In the dry year（2017）, warming and N addition, had no significant effect on these plant nutrient characteristics.（3） Significant differences in leaf N and P contents were found between the two species, and those of resorption efficiency were not observed.（4） Regression analysis indicated that N and P concentrations in plant leaves increased with soil N, P and water availability, while the resorption efficiency of plant N and P decreased with soil N, P and water availability. Research showed that the responses of nutrient resorption to warming and N addition could be mediated by variations of natural precipitation in a desert steppe.更多还原