Canopy radiation- and water-use efficiencies as affected by elevated [CO2]

Dafeng Hui, Yiqi Luo, Weixin Cheng, J. S. Coleman, Dale W. Johnson, Daniel A. Sims

Research output: Contribution to journalArticlepeer-review

49 Scopus citations

Abstract

This study used an environmentally controlled plant growth facility, EcoCELLs, to measure canopy gas exchanges directly and to examine the effects of elevated [CO2] on canopy radiation- and water-use efficiencies. Sunflowers (Helianthus annus var. Mammoth) were grown at ambient (399 μmol mol-1) and elevated [CO2] (746 μmol mol-1) for 53 days in EcoCELLs. Whole canopy carbon- and water-fluxes were measured continuously during the period of the experiment. The results indicated that elevated [CO2] enhanced daily total canopy carbon- and water-fluxes by 53% and 11%, respectively, on a ground-area basis, resulting in a 54% increase in radiation-use efficiency (RUE) based on intercepted photosynthetic active radiation and a 26% increase in water-use efficiency (WUE) by the end of the experiment. Canopy carbon- and water-fluxes at both CO2 treatments varied with canopy development. They were small at 22 days after planting (DAP) and gradually increased to the maxima at 46 DAP. When canopy carbon- and water-fluxes were expressed on a leaf-area basis, no effect of CO2 was found for canopy water-flux while elevated [CO2] still enhanced canopy carbon-flux by 29%, on average. Night-time canopy carbon-flux was 32% higher at elevated than at ambient [CO2]. In addition, RUE and WUE displayed strong diurnal variations, high at noon and low in the morning or afternoon for WUE but opposite for RUE. This study provided direct evidence that plant canopy may consume more, instead of less, water but utilize both water and radiation more efficiently at elevated than at ambient [CO2], at least during the exponential growth period as illustrated in this experiment.

Original languageEnglish (US)
Pages (from-to)75-91
Number of pages17
JournalGlobal change biology
Volume7
Issue number1
DOIs
StatePublished - 2001
Externally publishedYes

Keywords

  • Canopy development
  • Carbon flux
  • Elevated [CO]
  • Global change
  • Radiation-use efficiency
  • Sunflower
  • Water flux
  • Water-use efficiency

ASJC Scopus subject areas

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

Fingerprint

Dive into the research topics of 'Canopy radiation- and water-use efficiencies as affected by elevated [CO2]'. Together they form a unique fingerprint.

Cite this