Submitted to: Eastern Native Grass Symposium
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2002
Publication Date: October 21, 2004
Citation: GITZ, D.C., RITCHIE, J.C., KRIZEK, D.T., BAKER, J.T., REDDY, V.R. 2004. PROCEEDINGS OF THE THIRD EASTERN NATIVE GRASS SYMPOSIUM, THE NORTH CAROLINA BOTANICAL GARDEN, CHAPEL HILL, NC. P. 308. Technical Abstract: Eastern gamagrass [Tripsacum dactyloides (L.) L.] was grown in large 1 m3 bins on a sand:vermiculite mix with regular fertigation with a complete nutrient solution in closed transparent cuvettes (Soil Plant Atmosphere Research (SPAR) sunlit chambers) at 370 or 740 ppm CO2 and 20/14, 27.5/21.5 or 35/29 degree day/night temperatures. Plants were allowed to develop from mid-May to mid-October. Leaf and canopy photosynthesis was investigated. Results from leaf based observations were consistent with canopy level observations. Temperature effects on assimilation were much more pronounced than CO2 effects. Increased temperatures led to increased maximal assimilation rates, and quantum use efficiencies as Fv/Fm and CO2 assimilation vs PAR. In plants grown at lowest temperatures the maximum rate of carbon assimilation was reached at relatively low flux densities (maximal flux utilization 1500 umol m 2 s-1 PAR) as compared to high temperature plants (2500 umol m 2 s-1). Enhanced CO2 consistently decreased maximal flux utilization across treatments. This effect was most pronounced in plants grown at the lowest temperature regime.