Nitrate is an important nitrogen source for Arctic tundra plants

• Liu, Xue-Yan

• Koba, Keisuke

• Koyama, Lina A.

• Hobbie, Sarah E.

• Weiss, Marissa S.

• Inagaki, Yoshiyuki

• Shaver, Gaius R.

• Giblin, Anne E.

• Hobara, Satoru

• Nadelhoffer, Knute J.

• Sommerkorn, Martin

• Rastetter, Edward B.

• Kling, George W.

• Laundre, James A.

• Yano, Yuriko

• Makabe, Akiko

• Yano, Midori

• Liu, Cong-Qiang

Abstract

Plant nitrogen (N) use is a key component of the N cycle in terrestrial ecosystems. The supply of N to plants affects community species composition and ecosystem processes such as photosynthesis and carbon (C) accumulation. However, the availabilities and relative importance of different N forms to plants are not well understood. While nitrate (NO3−) is a major N form used by plants worldwide, it is discounted as a N source for Arctic tundra plants because of extremely low NO3− concentrations in Arctic tundra soils, undetectable soil nitrification, and plant-tissue NO3− that is typically below detection limits. Here we reexamine NO3− use by tundra plants using a sensitive denitrifier method to analyze plant-tissue NO3−. Soil-derived NO3− was detected in tundra plant tissues, and tundra plants took up soil NO3− at comparable rates to plants from relatively NO3−-rich ecosystems in other biomes. Nitrate assimilation determined by 15N enrichments of leaf NO3− relative to soil NO3− accounted for 4 to 52% (as estimated by a Bayesian isotope-mixing model) of species-specific total leaf N of Alaskan tundra plants. Our finding that in situ soil NO3− availability for tundra plants is high has important implications for Arctic ecosystems, not only in determining species compositions, but also in determining the loss of N from soils via leaching and denitrification. Plant N uptake and soil N losses can strongly influence C uptake and accumulation in tundra soils. Accordingly, this evidence of NO3− availability in tundra soils is crucial for predicting C storage in tundra.

Journal

• Proceedings of the National Academy of Sciences of the United States of America

  Proceedings of the National Academy of Sciences of the United States of America 115 (13), 3398-3403, 2018-03-27

  National Academy of Sciences

Keywords

• Arctic tundra plants
• nitrogen dynamics
• plant nitrate
• soil nitrate
• stable isotopes

Details

• CRID: 1050001335854848256
• NII Article ID: 120006416235
• ISSN: 00278424
• ISSN: 10916490
• DOI: 10.1073/pnas.1715382115
• HANDLE: 2433/230345
• Web Site: http://www.pnas.org/syndication/doi/10.1073/pnas.1715382115
• Web Site: https://pnas.org/doi/pdf/10.1073/pnas.1715382115
• Text Lang: en
• Article Type: journal article
• Data Source:
  • IRDB
  • Crossref
  • CiNii Articles
  • KAKEN