Plant nitrogen concentration, use efficiency, and contents in a tallgrass prairie ecosystem under experimental warming |
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Authors: | Yuan An &dagger ,Shiqiang Wan&dagger &Dagger ,Xuhui Zhou&dagger ,Afzal A. Subedar&dagger ,Linda L. Wallace&dagger , Yiqi Luo&dagger |
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Affiliation: | College of Agriculture and Biology, Shanghai Jiaotong University, Shanghai 201101, China,;Department of Botany and Microbiology, University of Oklahoma, Norman, OK 73019, USA,;Laboratory of Quantitative Vegetation Ecology, Institute of Botany, the Chinese Academy of Sciences, Xiangshan, Beijing 100093, China |
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Abstract: | Plant nitrogen (N) relationship has the potential to regulate plant and ecosystem responses strongly to global warming but has not been carefully examined under warmed environments. This study was conducted to examine responses of plant N relationship (i.e. leaf N concentration, N use efficiency, and plant N content in this study) to a 4‐year experimental warming in a tallgrass prairie in the central Great Plains in USA. We measured mass‐based N and carbon (C) concentrations of stem, green, and senescent leaves, and calculated N resorption efficiency, N use efficiency, plant N content, and C : N ratios of five dominant species (two C4 grasses, one C3 grass, and two C3 forbs). The results showed that warming decreased N concentration of both green and senescent leaves, and N resorption efficiency for all species. N use efficiencies and C : N ratios were accordingly higher under warming than control. Total plant N content increased under warming because of warming‐induced increases in biomass production that are larger than the warming‐induced decreases in tissue N concentration. The increases in N contents in both green and senescent plant tissues suggest that warming enhanced both plant N uptake and return through litterfall in the tallgrass ecosystem. Our results also suggest that the increased N use efficiency in C4 grasses is a primary mechanism leading to increased biomass production under warming in the grassland ecosystem. |
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Keywords: | global warming N concentration N resorption efficiency N use efficiency tallgrass prairie |
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