Increased nitrogen (N) input can potentially lead to secondary phosphorus (P) limitation; however, it remains unclear whether differences in the plant's ability to cope with this P deficiency are related to their growth responses. Using a long-term experiment of N addition in a boreal forest, we explored the potential role of plant nutrient resorption efficiency and its stoichiometry in mediating plant growth responses to increased N input. We recorded the cover and measured the concentration and resorption efficiency of leaf N and P as well as the photosynthesis of a grass and a shrub . The cover of the grass increased with increasing N addition, while that of the shrub decreased with N addition rate and almost disappeared from the high-level N addition over time. P resorption efficiency (PRE) increased in but decreased in with increasing leaf N:P which was increased by N addition for both species. In addition, photosynthesis increased linearly with N resorption efficiency (NRE) and PRE but was better explained by NRE:PRE, changing nonlinearly with the ratio in a hump-shaped trend. Furthermore, the variance (CV) of NRE:PRE for (123%) was considerably higher than that for (29%), indicating a more stable nutrient resorption stoichiometry of the grass. Taken together, these results highlight that efficient P acquisition and use strategy through nutrient resorption processes could be a pivotal underlying mechanism driving plant growth and community composition shifts under N enrichment.

中文翻译：

---

将养分吸收化学计量与长期氮添加下的植物生长联系起来


增加氮 (N) 输入可能会导致二次磷 (P) 限制；然而，目前尚不清楚植物应对磷缺乏的能力差异是否与其生长反应有关。通过在北方森林中进行长期氮添加实验，我们探索了植物养分吸收效率及其化学计量在调节植物生长对氮输入增加的反应中的潜在作用。我们记录了覆盖情况并测量了叶子氮和磷的浓度和吸收效率以及草和灌木的光合作用。草的覆盖度随着施氮量的增加而增加，而灌木的覆盖度则随着施氮量的增加而减少，并且随着时间的推移，高水平施氮量下几乎消失。 P 再吸收效率 (PRE) 随着叶片 N:P 的增加而增加，但随着叶片 N:P 的增加而减少，而两种物种的 N:P 均因添加 N 而增加。此外，光合作用随氮吸收效率（NRE）和PRE线性增加，但NRE：PRE可以更好地解释，随比例呈驼峰状趋势非线性变化。此外，(123%) 的 NRE:PRE 方差 (CV) 显着高于 (29%)，表明草的养分吸收化学计量更稳定。综上所述，这些结果表明，通过养分再吸收过程进行有效的磷获取和利用策略可能是在氮富集下驱动植物生长和群落组成变化的关键潜在机制。