Role of nitrogen supplementation in alleviating drought-associated growth and metabolic impairments in Phoebe zhennan seedlings

Drought is one of the major environmental stresses altering forest productivity. However, nutrient availability can modulate drought resistance. Phoebe zhennan (gold Phoebe) is a high‐quality timber‐producing but threatened tree species in China, facing serious anthropogenic disturbances and abiotic constraints that restrict its growth and development. However, little attention has been given to designing adaptive strategies for its management by evaluating the possible role of major nutrients, particularly nitrogen (N), on its morphological and physio‐biochemical responses under water stress. To evaluate these responses, a complete randomized design was followed to investigate the effects of two irrigation levels (well‐watered and drought‐stressed conditions) and N fertilization treatments (with and without N). Drought stress significantly affected the growth of seedlings, as indicated by impaired photosynthesis, pigment degradation, disrupted N metabolism, over‐production of reactive oxygen species and enhanced lipid peroxidation. Nitrogen supplementation under drought stress had remarkable positive effects on the growth through physio‐biochemical adjustments as shown by higher level of nitrogenous compounds and up‐regulation of N‐associated metabolic enzymes activities which might be due to N‐mediated improved leaf relative water contents and photosynthetic efficiency. In addition, N application reduced oxidative stress and membrane damage, and maintained a high accumulation of osmolytes. However, in well‐watered seedlings N fertilization significantly improved root biomass and net CO2 assimilation rate suggesting high N‐use efficiency of the seedlings. These findings reveal that drought significantly affects the growth of P. zhennan, while N fertilization plays a crucial role in alleviating water stress damage by improving its drought tolerance potential at low metabolic costs. Therefore, N fertilization could be considered as an effective strategy for the conservation and management of P. zhennan in the face of future climate change.Fil: Tariq, Akash. Chengdu Institute of Biology Chinese Academy of Sciences; China. Chinese Academy of Sciences; República de ChinaFil: Pan, Kaiwen. Chengdu Institute of Biology Chinese Academy of Sciences; ChinaFil: Olatunji, Olusanya Abiodun. Chinese Academy of Sciences; República de China. Chengdu Institute of Biology Chinese Academy of Sciences; ChinaFil: Graciano, Corina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Fisiología Vegetal. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Fisiología Vegetal; ArgentinaFil: Li, Ningning. Southwest University; ChinaFil: Li, Zilong. Chengdu Institute of Biology Chinese Academy of Sciences; China. Chinese Academy of Sciences; República de ChinaFil: Song, Dagang. Chinese Academy of Sciences; República de China. Chengdu Institute of Biology Chinese Academy of Sciences; ChinaFil: Sun, Feng. Chengdu Institute of Biology Chinese Academy of Sciences; China. Chinese Academy of Sciences; República de ChinaFil: Justine, Meta Francis. Chengdu Institute of Biology Chinese Academy of Sciences; China. Chinese Academy of Sciences; República de ChinaFil: Huang, Dan. Chengdu Institute of Biology Chinese Academy of Sciences; China. Chinese Academy of Sciences; República de ChinaFil: Gong, Shanxing. Chengdu Institute of Biology Chinese Academy of Sciences; ChinaFil: Pandey, Bikram. Chengdu Institute of Biology Chinese Academy of Sciences; China. Chinese Academy of Sciences; República de ChinaFil: Idrees, Muhammad. Chinese Academy of Sciences; República de China. Chengdu Institute of Biology Chinese Academy of Sciences; ChinaFil: Dakhil, Mohammed A.. Chinese Academy of Sciences; República de China. Chengdu Institute of Biology Chinese Academy of Sciences; China. Helwan University; Egipt