The species belonging to the genus Pistacia possess ecological, economic, and medicinal value. They show a very high ecological plasticity. This research is a contribution to the study of the intraspecific diversity and variability of 10 populations of Pistacia lentiscus in different bioclimates. Nine locations in Algeria and one site in France have been selected in order to understand the strategies developed by this species under extreme conditions, including altitude and aridity, and to identify the adaptive processes that can be observed based on the morphological and ultrastructural features of the leaf. As a result of this research, we have collected a large quantity of important information on morphological and microphytodermal leaf variability for the ten studied populations. The statistical analyses showed a very important difference in the studied characteristics between these populations. It has been demonstrated that environmental factors also have a significant impact on the heterogeneity of most measured leaf features. Moreover, the observations with the scanning electron microscope (SEM) enabled us to highlight new characteristics of the studied species, such as the glandular trichomes on the leaflets and embedded stomata in the epidermis. These criteria could supplement the existing morphological characteristics used in the systematic classification of the Pistacia genus. Overall, the studied species have shown xeromorphy features, which give them the opportunity to be used in desertification mitigation programs, due to their ability to withstand conditions of extreme aridity.
Keywords: altitude; aridity; leaf; macromorphology; stomata; trichome; ultrastructure; xeromorphic.