Morphological and physiological responses of desert plants to drought stress in a man-made landscape of the Taklimakan desert shelter belt

Drought and desertification have become a worldwide ecological problems, which pose new challenges for plant survival and adaptation. Thus, it is of great significance to explore the adaptive strategies of plants to drought stress for the survival and sustainable development of man-made ecosystem in desert. In this study, two drought treatments of control (10-day irrigation cycle) and drought (no irrigation) respectively were used to study the physiological and morphological acclimation of Haloxylon ammodendron (C.A. Mey) Bunge and Calligonum arborescens Litv, in a man-made landscape of the Taklimakan desert shelter belt. The results showed that not only significant difference for stomatal conductance and water potential was presented in this research for two species, but also the morphological difference. In response to drought, C. arborescens produced significantly shorter and thicker leaves, while H. ammodendron produced significantly shorter and thinner leaves. Additionally, for C. arborescens, non-structural carbohydrates (NSC) were significantly aggregated in the roots (P < 0.05), while in H. ammodendron NSC exhibited no significant change in leaves, stems, or roots, but significantly accumulated in the whole plant. The different leaf water potential Ψl for two species leading to a different WUE. In all, the two species exhibited different acclimation responses to drought, C. arborescens with a great higher WUE in drought, but H. ammodendron was smaller. Morphological adjustment was the main mechanism by which C. arborescens acclimated to drought, and it can be used as a "pioneer"sand-fixation species in deserts if resources enough. In contrast, H. ammodendron acclimated to drought by physiological adjustment dominated by stomatal closure, suggesting it could be used in sustainable development of ecological restoration areas.