Characteristics and Controlling Factors of Nutrient Resorption in Populus euphratica Oliv Across Various Environments

Populus euphratica Oliv, a representative species in arid ecosystems, serves vital ecological functions, including windbreak, sand stabilization and carbon sequestration. Investigating its nutrient resorption mechanisms is important for elucidating plant adaptation and growth strategies in nutrient-deficient environments. This study selected thirty sampling sites in Xinjiang across different locations and collected Populus euphratica leaves. Correlation analysis, regression analysis and redundancy analysis (RDA) were employed to assess the characteristics of nutrient resorption in Populus euphratica and their driving factors. We determined the leaf nitrogen (N) and phosphorus (P) concentrations in plants and then calculated the N:P ratio, nitrogen resorption efficiency (NRE) and phosphorus resorption efficiency (PRE). The results of the correlation analysis indicated that the NRE was not significantly correlated with the N and P contents or the N:P ratio in green leaves but was significantly related to those in senescent leaves. In contrast, the PRE was negatively correlated with the P content in the senescent leaves. The NRE:PRE ratio was positively correlated with the N in the green leaves and the P in the senescent leaves but negatively related to the N:P ratio in the senescent leaves. Nutrient resorption efficiency appeared to change with varying environments. Regression analysis revealed that both the NRE:PRE ratio and the NRE were positively correlated with latitude and mean annual precipitation (MAP) but negatively correlated with altitude and mean annual temperature (MAT). However, the PRE showed a negative correlation with latitude and MAP and positive correlations with altitude and MAT. Among these factors, the contribution of the MAP was the greatest, accounting for 85.1% and thus dominating the nutrient resorption processes in Populus euphratica. This study has enhanced the understanding of nutrient resorption conservation strategy and contributes to revealing the adaptation mechanisms of Populus euphratica under stress conditions such as drought and high temperatures.