Progress in studying heteromorphic leaves in Populus euphratica: leaf morphology, anatomical structure, development regulation and their ecological adaptation to arid environments

Populus euphratica Oliv. is a tree that is strongly resistant to drought and salt stress, which is primarily distributed in arid and semiarid lands. The leaves of the species exhibit a special feature that causes them to be designated as heterophylly. In this brief review, we primarily discuss the heteromorphic leaf development and anatomical features, such as the differentiation of spongy and palisade tissues, in heteromorphic leaves of the species. Furthermore, we also discuss the different physiological characteristics in heteromorphic leaves related to the ecological adaptation of P. euphratica to drought environments. These traits in P. euphratica may help researchers evaluate its ecological value in arid areas and evaluate its scientific merit in understanding the mechanism of development of heteromorphic leaves in plants.