Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 31, 1999
Publication Date: November 15, 1999
Citation: Kimball, B.A., Pinter Jr, P.J., Wall, G.W., La Morte, R.L., Adam, N.R., Ottman, M.J., Matthias, A.D., Brooks, T.J. 1999. The face sorghum project: preliminary results of elevated co2 and water deficit on fluxes of water, light, and carbon. Agronomy Abstracts p 16.
Field-grown grain sorghum [Sorghum bicolor (L.) Moench] was exposed to CO2 concentrations 200 umol/mol above ambient using free-air CO2 enrichment (FACE). Half of each main CO2 plot received ample water, while half received a deficit amount exposing plants to severe drought. Measurements were made of energy balance components from which evapotranspiration was calculated, of PAR absorption, and of carbon assimilation. Preliminary results indicate that there was an initial stimulation of photosynthesis and PAR absorptance by the elevated CO2 at ample water, but the effect disappeared shortly into the season. However, the elevated CO2 did promote some water conservation, so that with incipient water stress, the CO2-enriched sorghum continued photosynthesis longer into the drought cycle and had greater absorption and efficiency of light use.