Abstract:Phenotypic plasticity play the important role in the plant individual adaptation in extreme arid region. In this study, leaf anatomical structures of Populus euphratica were quantitatively analyzed to reveal the differences of phenotypic adaptive plasticity in three different soil conditions(Erdaoqiao, Qidaoqiao, Badaoqiao) in Egina, Innermongolia. The results showed that leaf anatomical structures of P. euphratica presented obvious divergence phenomenon in the heterogeneous soil conditions. Leaf anatomical structures of P. euphratica in Erdaoqiao, Qidaoqiao, Badaoqiao had different degrees of differences except main vein xylem/main vascular bundle area, and spongy tissue thickness had significant differences among three soil conditions. Soil moisture and salinity affected growth of epidermal tissue in represents of upper epidermal cell, and soil fertility affected growth of conducting tissue in represents of the main vein vascular bundle and palisade tissue in Ejina. Environmental heterogeneity is the root cause of leaf anatomical plasticity of P. euphratica. Leaf anatomical plasticity make P. euphratica adapt to different environments and different structures form adaptability difference in the same environment. Variation coefficient and plasticity index of the main vein xylem area and the main vein vascular bundle area were high, which showed main vein xylem and main vein vascular bundle were the major structure of P. euphratica in response to conditional changes. Leaf anatomical structure characteristics and its plasticity are the important adaptive strategy of P. euphratica in the dryland.