AUTHOR=Yang Guojiao , Zhang Zijia , Zhang Guangming , Liu Qianguang , Zheng Peiming , Wang Renqing TITLE=Tipping point of plant functional traits of Leymus chinensis to nitrogen addition in a temperate grassland JOURNAL=Frontiers in Plant Science VOLUME=Volume 13 - 2022 YEAR=2022 URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.982478 DOI=10.3389/fpls.2022.982478 ISSN=1664-462X ABSTRACT=It has widely been documented that nitrogen (N) enrichment stimulates plant growth in grassland, there is a need to better understand the critical transitions or tipping point for the responses of plant growth to N enrichment. We chose the native, perennial clonal grass, Leymus chinensis in Inner Mongolia steppe, and conducted a field experiment, which six N addition rates (0, 2, 5, 10, 20, and 50 g N m–2 year–1) with five N compound types are considered. Here, we found that the different N compound types had no significant effect on the growth of L. chinensis. N addition rate significantly increased plant aboveground biomass and leaf nitrogen content, whereas decreases leaf dry matter content. The tipping point for N-induced aboveground biomass increase is at 10 g N m –2 year –1, and that changes in functional traits is at N addition rates of 20 g N m –2 year –1, our findings suggest that the responses of aboveground biomass and functional traits to N addition were asymmetric, in which aboveground biomass were more sensitive. In addition, this work found that soil inorganic N content and soil pH, not functional traits of L. chinensis were primary indicators associated with aboveground biomass increase under N deposition. The differential sensitivity of aboveground biomass and functional traits of L. chinensis occurred to N deposition highlights the importance of functional traits in mediating ecosystem functioning in the face of global changes.