Facilities: Reno
Frits Went Laboratory (B. Coulombe)

EcoCELL Research Publications

Hui D., Luo Y., Cheng W., Coleman J.S., Johnson D.W., and Sims D.A. (2001): Canopy radiation- and water-use efficiencies as effected by elevated [CO₂]. Global Change Biology 7(1): 75-92.

Abstract: This study used an environmentally controlled plant growth facility EcoCELLs to directly measure canopy gas exchanges and to examine the effects of elevated [CO2] on canopy radiation and water use efficiencies. Sunflowers (Helianthus annuus 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 continuously measured 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 the 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 the 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. Nighttime 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 water and radiation more efficiently at elevated than at ambient [CO2], at least during the exponential growth period as illustrated in this experiment.

Ecocell Specifications
EcoCELL cross sectional view
EcoCELL Research Publications

For more information on the EcoCELLs, please contact Mr. Bill Coulombe at (775) 674-7038 or via email at Bill.Coulombe@dri.edu.