Objective The study of shrub and grass plants suitable for survival in the arid and semi-arid regions of Northwest China can not only improve the ecological environment of Northwest China, but also conform to the concept of sustainable development, which is of far-reaching significance for the ecological restoration and the water-saving and carbon-sink-enhancing work in the region.

Method Based on the field survey and literature research of local dominant plants, this study selected ten herbaceous plants and seven shrubs as research objects. Field experiments were conducted, then their growth trait indexes, photosynthesis physiological indexes, biomass and carbon storage indexes were tested. The hierarchical analysis method was applied to comprehensively evaluate the water-saving and carbon-sink-enhancing performance of herbaceous plants and shrubs, respectively, so as to screen out the suitable plant species.

Result (1) In herbaceous plants, water-use efficiencies of Agropyron elongatum, Astragalus laxmannii and Poa annua were high. In shrubs, water-use efficiencies of Juniperus sabina, Caragana korshinskii, and Amorpha fruticosa were high. (2) In herbaceous plants, total carbon stocks of Medicago sativa, Melilotus officinalis, and Astragalus laxmannii were high. In shrubs, total carbon stocks of Amorpha fruticosa, Caragana korshinskii, and Hippophae rhamnoides were high. (3) Water-saving and carbon-sink-enhancing herbs ranked in descending order of Medicago sativa > Melilotus officinalis > Astragalus laxmannii > Alcea rosea > Elymus dahuricus > Artemisia desertorum > Agropyron elongatum > Festuca elata > Lolium perenne > Poa annua. Water-saving and arbon-sink-enhancing shrubs ranked in descending order of Amorpha fruticosa > Caragana korshinskii > Hippophae rhamnoides > Juniperus sabina > Lespedeza bicolor > Salix cheilophila > Corethrodendron scoparium.

Conclusion The study has screened out water-saving and carbon-sink-enhancing plant species suitable for survival in the arid and semi-arid regions of Northwest China. It can not only provide a basis for the plant configuration in the region, and improve ecological environment, but also provide scientific and technological support for ecological reconstruction and increase of carbon sinks in the region.