Drought stress is an important limiting factor of plant performance, and how it interacts with increasing nitrogen (N) deposition to affect seedling development requires further investigation. This study addresses the combined effects of N deposition and drought on growth and physiological attributes of Phyllostachys edulis (Carr.) seedlings. Seedling growth attributes and nitrogen metabolism indicators were evaluated after the fast-growing period in the presence of four simulated N deposition rates (control, 0 kg·ha−1·yr−1; low N, 30; medium N, 60; high N, 90) and two watering conditions (normal, 75 ± 5% of field capacity; or drought, 35 ± 5%). Drought stress significantly inhibited P. edulis seedling growth and N metabolism. Under normal watering conditions, greater simulated N deposition was associated with higher seedling component mass, free amino acid and soluble protein content in leaves, and enzyme activity related to N metabolism. Under drought conditions, medium N deposition maximized seedling component mass and enzyme activity related to N metabolism. Overall, low and medium N deposition improved seedling performance under drought conditions, but high N deposition did not. Moderate N deposition can partially offset the negative effects of drought stress on P. edulis seedling development.

中文翻译：

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不同浇水条件下模拟氮沉降对毛竹幼苗的影响：幼苗耐旱性与氮代谢有关吗？

干旱胁迫是植物性能的重要限制因素，它如何与增加的氮 (N) 沉积相互作用以影响幼苗发育需要进一步研究。本研究探讨了氮沉积和干旱对 Phyllostachys edulis (Carr.) 幼苗生长和生理特性的综合影响。在四种模拟氮沉积速率（对照，0 kg·ha-1·yr-1；低氮，30；中氮，60；高氮）存在下，评估快速生长期后的幼苗生长属性和氮代谢指标, 90) 和两种浇水条件（正常，田间持水量的 75 ± 5%；或干旱，35 ± 5%）。干旱胁迫显着抑制 P. edulis 幼苗生长和氮代谢。在正常浇水条件下，较大的模拟氮沉积与较高的幼苗组分质量有关，叶中游离氨基酸和可溶性蛋白含量，以及与氮代谢相关的酶活性。在干旱条件下，中等氮沉积使幼苗组分质量和与氮代谢相关的酶活性最大化。总体而言，低氮和中氮沉积改善了干旱条件下的幼苗性能，但高氮沉积没有。适度的氮沉降可以部分抵消干旱胁迫对青蒿幼苗发育的负面影响。