Photosynthesis Research

, Volume 66, Issue 1, pp 79–95

Acclimation response of spring wheat in a free-air CO2 enrichment (FACE) atmosphere with variable soil nitrogen regimes. 2. Net assimilation and stomatal conductance of leaves

Authors

    • Agricultural Research Service, US Department of AgricultureUS Water Conservation Laboratory
  • Neal R. Adam
    • Agricultural Research Service, US Department of AgricultureUS Water Conservation Laboratory
    • Department of Plant Biology and Center for Early Events in PhotosynthesisArizona State University
  • Talbot J. Brooks
    • Maricopa Agricultural CenterUniversity of Arizona
  • Bruce A. Kimball
    • Agricultural Research Service, US Department of AgricultureUS Water Conservation Laboratory
  • Paul J. PinterJr.
    • Agricultural Research Service, US Department of AgricultureUS Water Conservation Laboratory
  • Robert L. LaMorte
    • Agricultural Research Service, US Department of AgricultureUS Water Conservation Laboratory
  • Floyd J. Adamsen
    • Agricultural Research Service, US Department of AgricultureUS Water Conservation Laboratory
  • Douglas J. Hunsaker
    • Agricultural Research Service, US Department of AgricultureUS Water Conservation Laboratory
  • Gabrielle Wechsung
    • Department of Soil ScienceHumboldt University of Berlin
    • Department of Plant Biology and Center for Early Events in PhotosynthesisArizona State University
  • Frank Wechsung
    • Potsdam-Institute for Climate Impact Research
  • Susanne Grossman-Clarke
    • Potsdam-Institute for Climate Impact Research
  • Steven W. Leavitt
    • Laboratory of Tree-Ring ResearchUniversity of Arizona
  • Allan D. Matthias
    • Department of Soil, Water, and Environmental ScienceUniversity of Arizona
  • Andrew N. Webber
    • Department of Plant Biology and Center for Early Events in PhotosynthesisArizona State University
Article

DOI: 10.1023/A:1010646225929

Cite this article as:
Wall, G.W., Adam, N.R., Brooks, T.J. et al. Photosynthesis Research (2000) 66: 79. doi:10.1023/A:1010646225929

Abstract

Atmospheric CO2 concentration continues to rise. It is important, therefore, to determine what acclimatory changes will occur within the photosynthetic apparatus of wheat (Triticum aestivum L. cv. Yecora Rojo) grown in a future high-CO2 world at ample and limited soil N contents. Wheat was grown in an open field exposed to the CO2 concentration of ambient air [370 μmol (CO2) mol−1; Control] and air enriched to ∼200 μmol (CO2) mol−1 above ambient using a Free-Air CO2 Enrichment (FACE) apparatus (main plot). A High (35 g m−2) or Low (7 and 1.5 g m−2 for 1996 and 1997, respectfully) level of N was applied to each half of the main CO2 treatment plots (split-plot). Under High-N, FACE reduced stomatal conductance (gs) by 30% at mid-morning (2 h prior to solar noon), 36% at midday (solar noon) and 27% at mid-afternoon (2.5 h after solar noon), whereas under Low-N, gs was reduced by as much as 31% at mid-morning, 44% at midday and 28% at mid-afternoon compared with Control. But, no significant CO2 × N interaction effects occurred. Across seasons and growth stages, daily accumulation of carbon (A′) was 27% greater in FACE than Control. High-N increased A′ by 18% compared with Low-N. In contrast to results for gs, however, significant CO2 × N interaction effects occurred because FACE increased A′ by 30% at High-N, but by only 23% at Low-N. FACE enhanced the seasonal accumulation of carbon (A′′) by 29% during 1996 (moderate N-stress), but by only 21% during 1997 (severe N-stress). These results support the premise that in a future high-CO2 world an acclimatory (down-regulation) response in the photosynthetic apparatus of field-grown wheat is anticipated. They also demonstrate, however, that the stimulatory effect of a rise in atmospheric CO2 on carbon gain in wheat can be maintained if nutrients such as nitrogen are in ample supply.

acclimationclimate changeCO2down-regulationglobal changephotosynthesisstomatal conductance
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© Kluwer Academic Publishers 2000