Response of Twig-Leaf Size Relationships Populus euphratica with Heteromorphic Leaves to Drought Stress

【Objective】The purpose of this study is to analyze whether changes in the twig-leaf size relationships could reduce the drought stress of Populus euphratica with heteromorphic leaves, which could provide reference for clarifying the formation mechanism of heteromorphic leaves and the conservation of P. euphratica individuals.【Method】Three main heteromorphic leaves, i.e., ovate, nearly ovate and lanceolate leaf, of P. euphratica in the Ebinur Lake Wetland National Nature Reserve in the Xinjiang, China, were taken as the research object. The cross-sectional area of twigs, the total leaf area on the twigs, the hydraulic and anatomical traits were determined experimentally in 18 P. euphratica individuals, and then the standardized major axis regression（SMA） was used to compare the difference in the relationship of size between twig and leaf among three heteromorphic leaves. Multi-correlation analysis was conducted to test the effects of the twig-leaf size relationships on the hydraulic and anatomical traits.【Resu