Abstract: In this study,the leaf morphological and structural features of Populus euphratica at different growing stages and their relationships with DBH were researched. Results are as follows: ① Along with the increase of DBH and crown level from the base to the top,the leaf width,area,stomatal density and thickness of leaves of P.euphratica were gradually increased,while the leaf length and leaf index(leaf length/leaf width) were steadily decreased; ② The cell number,length of epidermal cells and thickness,and length and width of palisade tissue were gradually increased with the increase of diameter at breast height and crown level(from base to top),while the thickness of spongy tissue was gradually decreased with the increase of diameter at breast height but increased gradually from the base to the top; ③ Correlation analysis revealed that there were the extremely significant or significant positive correlations between the DBH and the leaf width,area and thickness,but there was a significant negative one between DBH and leaf index. There were the significant positive or negative correlations between palisade tissue thickness,epidermal cell length,cell number,thickness of epidermal tissue and DBH. There was a significant negative correlation between thickness of spongy tissue and DBH. There were also the significant positive or negative correlation between leaf morphological parameters and leaf anatomical and structure parameters.

Key words: Populus euphratica, heterophyll, leaf morphology, anatomy, diameter at breast height