Abstract: [Objective] This study aimed to investigatethe effects of nitrogen (N) and water addition on the leaf traits of dominant plant species in Artemisia ordosica community of the Mu Us Desert, and to explore the adaptive strategies of different functional groups of plants in response to increased N deposition and precipitation, which would help predict the changes of plant community composition under future global environmental changes.[Method] We conducted a field experiment simulating two levels of N deposition (N0:ambient level of nitrogen; N60:60 kg N·hm^-2 a^-1) and with three levels of precipitation (W0:ambient precipitation; W20:ambient precipitation+20%; and W40:ambient precipitation+40%) from 2015 to 2016 in a shrubland dominated by A. ordosica in the Mu Us Desert of northern China.We examined the specific leaf area (SLA), leaf carbon (C) concentration, leaf N concentration and leaf phosphorus (P) concentration of two dominant plant species Artemisia ordosica(shrub) and Leymus secalinus (grass)in an A. ordosica community, and assessed responses of the desert plant leaf traits to N and water addition.[Result] 1) The result showed that soil inorganic N concentrations significantly increased only in plots with added N, and soil moisture significantly increased only in plots with added water.Nitrogen, water addition, and their interaction had non-significant effects on soil available P. 2) Nitrogen and water addition significantly increased the SLA of A. ordosica, but had limited effects on the SLA of L. secalinus. There was a significant interaction between N and water addition affecting the SLA of L. secalinus.3)Nitrogen addition had no effects on leaf C concentration, but significantly on leaf N concentration, C:P and N:P, and decreased leaf P concentration and C:N of A. ordoscia and L. secalinus. Water addition had no significant effect on leaf C, N, P concentration and stoichiometric ratios of L. secalinus, but significantly increased leaf N and P concentration and decreased leaf C concentration,C:N, C:P and N:P atios of A. ordosica. There was a significant interaction between N and water addition on the leaf N concentration and C:N ratio of A. ordosica.[Conclusion] Taken together,the results demonstrated that nitrogen and water had significant effects on leaf traits of A. ordoscia and L. secalinus, the dominant plants of Artemisia ordosica community in Mu Us sandy land, and the N effectwas more significant than the water.Our results suggest that A. ordosica may tend to adopt aggressive resource-use strategy, while L. secalinus may tend to adopt more conservativeresource-use strategyin response to concurrent alterations in N and water supply. The species composition of A. ordosica community might change due to the different resource-use strategy of two plants under future global environmental changes.

Key words: leaf traits, resource-use strategy, Artemisia ordosica community, nitrogen deposition, global environmental changes, desert ecosystems