Gas exchange and water relations of spring wheat under full-season infrared warming

Gerard W. Wall, Bruce A. Kimball, Jeffrey W. White, Michael J. Ottman

Research output: Contribution to journalArticlepeer-review

64 Scopus citations


Gas exchange and water relations were evaluated under full-season in situ infrared (IR) warming for hard red spring wheat (Triticum aestivum L. cv. Yecora Rojo) grown in an open field in a semiarid desert region of the southwest USA. A temperature free-air controlled enhancement (T-FACE) apparatus utilizing IR heaters maintained canopy air temperature above 3.0m Heated plots of wheat by 1.3 and 2.7°C (0.2 and 0.3°C below the targeted set-points of Reference plots with dummy heaters) during daytime and nighttime, respectively. Control plots had no apparatus. Every 6 weeks during 2007-2009 wheat was sown under the three warming treatments (i.e., Control, Heated, Reference) in three replicates in a 3 × 3 Latin square (LSQ) design on six plantings during 4 months (i.e., January, March, September, December), or in a natural temperature variation treatment (i.e., Control) in three replicates in a randomized complete block (RCB) design on nine plantings during 7 months (i.e., January, February, April, June, July, August, October). Soil temperature (Ts) and volumetric soil-water content (θs) were 1.3°C warmer and 14% lower in Heated compared with Reference plots, respectively. Other than a 1% shading effect, no artifacts on gas exchange or water relations were associated with the IR warming apparatus. IR warming increased carbon gain characteristic of an increase in metabolic rates to higher temperature that may have been attributed to the well-watered wheat crop and the supplemental irrigation that minimized plant-to-air water vapor pressure differences between IR-warmed and nonwarmed plots. Nevertheless, seasonal oscillations in the IR warming response on carbon gain occurred. IR warming decreased leaf water status and provided thermal protection during freeze events. IR warming is an effective experimental methodology to investigate the impact of global climate change on agronomic cropping and natural ecosystems to a wide range of natural and artificially imposed air temperatures. Published 2011. This article is a US Government work and is in the public domain in the USA.

Original languageEnglish (US)
Pages (from-to)2113-2133
Number of pages21
JournalGlobal change biology
Issue number6
StatePublished - Jun 2011


  • Climate change
  • Global change
  • Infrared radiation
  • Net assimilation rate
  • Stomatal conductance
  • Supplemental temperature
  • Water stress
  • Wheat (Triticum aestivum L.)

ASJC Scopus subject areas

  • Global and Planetary Change
  • Environmental Chemistry
  • Ecology
  • Environmental Science(all)


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