Concurrent ground-level ozone (O3) pollution and anthropogenic nitrogen (N) deposition can markedly influence dynamics and productivity in forests.Most studies evaluating the functional traits responses of rapid-turnover organs to O3 have specifically examined leaves,despite fine roots are another major source of soil carbon and nutrient input in forest ecosys-tems.How elevated O3 levels impact fine root biomass and biochemistry remains to be re-solved.This study was to assess poplar leaf and fine root biomass and biochemistry re-sponses to five different levels of O3 pollution,while additionally examining whether four levels of soil N supplementation were sufficient to alter the impact of O3 on these two organs.Elevated O3 resulted in a more substantial reduction in fine root biomass than leafbiomass;relative to leaves,more biochemically-resistant components were present within fine root litter,which contained high concentrations of lignin,condensed tannins,and elevated C:N and lignin:N ratios that were associated with slower rates of litter decomposition.In con-trast,leaves contained more labile components,including nonstructural carbohydrates and N,as well as a higher N:P ratio.Elevated O3 significantly reduced labile components and in-creased biochemically-resistant components in leaves,whereas they had minimal impact on fine root biochemistry.This suggests that O3 pollution has the potential to delay leaf litter decomposition and associated nutrient cycling.N addition largely failed to affect the impact of elevated O3 levels on leaves or fine root chemistry,suggesting that soil N supplementation is not a suitable approach to combating the impact of O3 pollution on key functional traits of poplars.These results indicate that the significant differences in the responses of leaves and fine roots to O3 pollution will result in marked changes in the relative belowground roles of these two litter sources within forest ecosystems,and such changes will independently of nitrogen load.

Pin Li;Rongbin Yin;Huimin Zhou;Sheng Xu;Zhaozhong Feng

Research Center for Urban Forestry,Key Laboratory for Forest Silviculture and Conservation of Ministry of Education,Key Laboratory for Silviculture and Forest Ecosystem Research in Arid-and Semi-arid Region of State Forestry Administration,Beijing Forestry University,Beijing 100083,China;State Key Laboratory of Urban and Regional Ecology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China;Key Laboratory of Forest Ecology and Management,Institute of Applied Ecology,Chinese Academy of Sciences,Shenyang 110016,China;Institute of Ecology,Key Laboratory of Agrometeorology of Jiangsu Province,School of Applied Meteorology,Nanjing University of Information Science and Technology,Nanjing 210044,China

环境科学学报（英文版）

[1]Pin Li;Rongbin Yin;Huimin Zhou;Sheng Xu;Zhaozhong Feng-.Functional traits of poplar leaves and fine roots responses to ozone pollution under soil nitrogen addition)[J].环境科学学报（英文版）,2022(03):118-131

leafbiomass,poplars

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