Interactive effects of elevated CO2 and precipitation change on leaf nitrogen of dominant Stipa L. species

Ecology and Evolution

Yaohui Shi¹  Guangsheng Zhou¹  Yanling Jiang¹  Hui Wang¹  Zhenzhu Xu¹ 

[1] State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China

关键词: Elevated CO2;    interactive effect;    leaf N concentration;    precipitation change;    Stipa L.;   

DOI  :  10.1002/ece3.1581

来源: Wiley

【 摘 要 】

Abstract

Nitrogen (N) serves as an important mineral element affecting plant productivity and nutritional quality. However, few studies have addressed the interactive effects of elevated CO₂ and precipitation change on leaf N of dominant grassland genera such as Stipa L. This has restricted our understanding of the responses of grassland to climate change. We simulated the interactive effects of elevated CO₂ concentration and varied precipitation on leaf N concentration (N_mass) of four Stipa species (Stipa baicalensis, Stipa bungeana, Stipa grandis, and Stipa breviflora; the most dominant species in arid and semiarid grassland) using open-top chambers (OTCs). The relationship between the N_mass of these four Stipa species and precipitation well fits a logarithmic function. The sensitivity of these four species to precipitation change was ranked as follows: S. bungeana > S. breviflora > S. baicalensis > S. grandis. The N_mass of S. bungeana was the most sensitive to precipitation change, while S. grandis was the least sensitive among these Stipa species. Elevated CO₂ exacerbated the effect of precipitation on N_mass. N_mass decreased under elevated CO₂ due to growth dilution and a direct negative effect on N assimilation. Elevated CO₂ reduced N_mass only in a certain precipitation range for S. baicalensis (163–343 mm), S. bungeana (164–355 mm), S. grandis (148–286 mm), and S. breviflora (130–316 mm); severe drought or excessive rainfall would be expected to result in a reduced impact of elevated CO₂. Elevated CO₂ affected the N_mass of S. grandis only in a narrow precipitation range. The effect of elevated CO₂ reached a maximum when the amount of precipitation was 253, 260, 217, and 222 mm for S. baicalensis, S. bungeana, S. grandis, and S. breviflora, respectively. The N_mass of S. grandis was the least sensitive to elevated CO₂. The N_mass of S. breviflora was more sensitive to elevated CO₂ under a drought condition compared with the other Stipa species.

【 授权许可】

CC BY   
© 2015 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.

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