Direct inhibition of leaf dark respiration by elevated CO2 is minor in 12 grassland species

Authors

  • M. G. Tjoelker,

    Corresponding author
    1. Department of Forest Resources, University of Minnesota, 1530 Cleveland Ave. N., St. Paul, MN, 55108, USA;
    2. Current address, Department of Forest Science, Texas A & M University, College Station, TX, 77843–2135, USA
      Author for correspondence: M. G. Tjoelker Tel: +979 845 8279 Fax: +979 845 6049 Email:m-tjoelker@tamu.edu
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  • J. Oleksyn,

    1. Department of Forest Resources, University of Minnesota, 1530 Cleveland Ave. N., St. Paul, MN, 55108, USA;
    2. Polish Academy of Sciences, Institute of Dendrology, Parkowa 5, PL-62–035, Kórnik, Poland;
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  • T. D. Lee,

    1. Department of Forest Resources, University of Minnesota, 1530 Cleveland Ave. N., St. Paul, MN, 55108, USA;
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  • P. B. Reich

    1. Department of Forest Resources, University of Minnesota, 1530 Cleveland Ave. N., St. Paul, MN, 55108, USA;
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Author for correspondence: M. G. Tjoelker Tel: +979 845 8279 Fax: +979 845 6049 Email:m-tjoelker@tamu.edu

Summary

  • •  Direct inhibition of dark respiration by elevated atmospheric concentrations of CO2 could alter the carbon balance of plants and ecosystems. The short-term response of leaf dark respiration to elevated CO2 concentrations are reported here in 12 grass and forb species of a North American grassland community.

  • •  Specific respiration rates at 25°C and a range of measurement CO2 concentrations were determined for detached leaves of each species field-grown in monoculture.

  • •  On average, respiration rates were 1.8% lower at 700 than at 360 µmol mol−1 CO2. Among species, responses ranged from a 6.4% inhibition to a 2.4% stimulation and were generally not statistically significant. Across a range of CO2 concentrations from 360 to 1300 µmol mol−1, respiration rates declined linearly and were 11% lower at 1300 than 360 µmol mol−1 CO2.

  • •  Direct inhibition of leaf respiration is small compared with other longer-term, indirect effects of CO2 on carbon exchange. The direct effects of rising atmospheric CO2 concentrations on respiration rates should result in minimal effects on plant carbon exchange in grasslands.

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