L-Arginine Enhances Stress Resilience Against P Deficiency of Chinese Fir in Root System: Physiological and Proteomics Analysis

The diminishing availability of phosphorus (P) in soils poses a significant constraint, impacting over 30 % of global agricultural and forestry production. Root exudates play a crucial role in, helping plants cope with environmental stress and facilitating communication between plants. Conducting physiological and proteomic analyses under low P and L-arginine treatments, this study delved into the internal regulatory mechanisms of Larginine in Chinese fir under low P conditions. Adding L-arginine not only expanded the root length and surface area but also substantially improved the P accumulate capacity of Chinese fir. Physiological examinations revealed a notable increase in peroxidase (POD) activity by 81.10 % and superoxide dismutase (SOD) activity by 31.39 % with the addition of L-arginine under low P conditions. Proteomics analysis further demonstrated that Larginine significantly downregulated the expression of phosphate transporters (PHTs) while concurrently upregulating POD expression. The regulation extended beyond POD activity, involving the expression of anthocyanidin synthase, showcasing L-arginine's comprehensive impact on stress tolerance in Chinese fir under low P conditions. It established that the exogenous addition of L-arginine regulated the root development and enhanced P absorption and uptake. This strategic supplementation strengthens the stress resistance of Chinese fir to low P, offering valuable insights into root secretion mechanisms in response to adaptive strategies in a low P environment.