C4 plant species and geographical distribution in relation to climate in the desert vegetation of China

Water use efficiency of C4 plants is higher than that of C3 plants, and CAM (Crassulaceae Acid Metabolism) plants have the highest water use efficiency. In the desert regions of China, CAM plants are scarce, and C4 plants, especially C4 woody plants, have an important position and role in the desert ecosystem. There are 45 species of C4 woody plants in the desert regions of China, including semi-woody plants, accounting for 6% of the total desert plant species in China, and most of them are concentrated in the families of Chenopodiaceae and Polygonaceae, which are 19 species and 26 species, respectively. The number of C4 herbaceous plants is 107 species, including 48 monocot species and 59 dicot species. C4 woody plants mainly inhabit the northwestern arid desert regions of China west of the Helan Mountains. The drought-resistance and drought-tolerance of C4 herbaceous plants are worse than C4 woody plants, and C4 herbaceous plants mainly inhabit areas with shallow groundwater depth and better water conditions in the desert regions, and are widely distributed along the margins of oases. The abundance of C4 woody plants is closely correlated with drought, but the abundance of C4 herbaceous plants increases with wet conditions.