Adaptation Strategies of Populus euphratica to Arid Environments Based on Leaf Trait Network Analysis in the Mainstream of the Tarim River

Abstract

Populus euphratica, a key tree species in the ecologically fragile area of the Tarim River Basin, plays a crucial role in maintaining the ecological balance of the desert. In order to explore the response of Populus euphratica leaves to river water resources and drought climate change, the complex topological relationship between the leaf traits of Populus euphratica was comprehensively analyzed by establishing the leaf trait network of the mainstream of the Tarim River, and the central traits that play a key role in regulating the phenotype of Populus euphratica were identified. The adaptation strategies of Populus euphratica to different environments were clarified from the perspective of the overall leaf trait network. The results show that, with a decrease in river water flow, the internal coordination of the leaf traits weakened, forming a looser network structure. In the hyper-arid region, the leaf traits were more independent, the network was simpler, and it was easier for the leaf to coordinate the aggregation of specific traits. Leaf thickness and the related photosynthetic traits are the key to adaptive strategies, particularly the cuticle thickness and midvein vascular bundle area. Leaf anatomical traits are more critical than stoichiometry traits in drought resistance. Leaves tend to give priority to the relationship between structural traits. Populus euphratica leaves adjust their trait modularization through a trait substitution strategy to manage different drought conditions.