Abstract:In order to compare the differences in functional traits and the response mechanism to summer heat wave between desert native shrubs and urban greening shrubs, four water-related functional traits (hydraulic, leaf, photosynthetic, and carbon economic traits) of 9 desert native shrubs and 8 urban native shrubs were measured, and the damage degree of plants was investigated at the end of summer heat wave in northern Xinjiang in 2022. The results showed that nearly 74% of desert native shrubs were not damaged during the summer heat wave, whereas 56% of urban greening shrubs were damaged. In terms of hydraulic and leaf traits, the mean values of water potential, leaf dry matter content, and xylem vessel diameter of desert shrubs were lower than those of urban greening shrubs, while the twig specific hydraulic conductivity, the quasi-steady water conductivity, Huber value, specific leaf area, and xylem vessel density showed opposite patterns. With regarding to carbon economy and photosynthetic traits, the soluble carbon content and water use efficiency of desert native shrubs were higher than those of urban green shrub (P<0.05), the stomatal conductance showed an opposite pattern (P<0.05), but there were no significant differences in transpiration rate, starch and non-structural carbon content and transpiration rate (P>0.05). The traits integration of desert native shrubs (G=0.39) was higher than that of urban greening shrubs (G=0.20). The numbers of key nodes and their associated trait pairs in the desert native shrubs were higher than urban greening shrubs. The results suggested that the drought-induced damages of desert native shrubs caused by summer heat wave in 2022 were lower than those of urban green shrubs. The reason is that desert plants have stronger ability of water absorption, transport, and reducing transpiration loss than urban greening shrubs because of their advantages in water-related functional traits and trait integration. At the same time, compared with urban greening shrubs, the desert shrubs can coordinate the relationship among functional traits and adopt more diversified mechanisms to reduce the negative effects of summer heat wave. Our study provides scientific reference for the selection of urban greening shrubs and the formulation of regional ecological protection policies in arid regions.