Nutrient resorption from senescing leaves is an important process of internal nutrient cycling in plants, but the patterns of nutrient resorption and the coupled relationship between nitrogen (N) and phosphorus (P) in plant leaves as affected by N deposition remain unclear. We analysed the effects of N addition on the nutrient resorption and coupled relationship between N and P in plant leaves under different nutrient-limited conditions based on a global meta-analysis. Globally, the mean N resorption efficiency (NRE) and P resorption efficiency (PRE) under natural conditions were 47.4% and 53.6%, respectively, which were significantly regulated by geographical and climatic factors as well as plant characteristics. Furthermore, N addition significantly decreased the NRE by 13.3% but slightly affected the PRE on a global scale, and N addition rates and latitude directly and negatively affected the effects of N addition on NRE. Specifically, N addition significantly decreased the NRE under all nutrient-limited conditions, while it had negative, positive, and neutral effects on the PRE under N-limited, P-limited, and N and P-co-limited conditions, respectively. Moreover, the relationships between N and P in green and senesced leaves were tightly coupled under different nutrient-limited conditions in natural ecosystems. However, N addition significantly weakened the relationships between N and P concentrations in green leaves but slightly affected the relationship in senesced leaves, which were mainly modulated by the effects of N addition on nutrient resorption efficiency, especially NRE. These results highlight that nutrient-limited conditions determine the response of nutrient resorption to N deposition and emphasize the effect of nutrient resorption regulation on the coupling of N and P responses to N enrichment. The findings are important for understanding plant nutrient use strategies and the mechanisms underlying the stoichiometric coupling of N and P in response to climate change, and can be used in global biogeochemical models.

衰老叶片中的养分吸收是植物内部养分循环的重要过程，但受氮沉降影响的养分吸收模式以及氮（磷）与磷在土壤中的耦合关系仍然不清楚。我们基于全球荟萃分析，分析了氮素添加对不同养分限制条件下植物叶片养分吸收和氮磷耦合关系的影响。全球范围内，自然条件下的平均氮吸收效率（NRE）和磷吸收效率（PRE）分别为47.4％和53.6％，这受到地理和气候因素的显着调节。以及植物特征。此外，氮的添加使NRE显着降低了13.3％，但在全球范围内对PRE的影响很小，并且N的添加率和纬度直接和负面地影响了N的添加对NRE的影响。具体而言，氮添加在所有营养限制条件下均显着降低NRE，而分别在氮限制，P限制以及N和P-co限制条件下对PRE产生负，正和中性作用。此外，在自然生态系统中，在不同养分限制条件下，绿色和衰老叶片中氮和磷之间的关系紧密相关。然而，氮的添加显着削弱了绿叶中氮和磷浓度之间的关系，但对衰老叶片中的氮和磷浓度之间的关系有轻微的影响，这主要是由氮的添加对养分吸收效率的影响所调节的，尤其是NRE。这些结果表明，养分有限的条件决定了养分吸收对氮沉降的响应，并强调了养分吸收调节对氮素和磷响应氮素富集耦合的影响。这些发现对于理解植物养分的使用非常重要 N和P响应气候变化的化学计量耦合的基本策略和机制，可用于全球生物地球化学模型。