Submitted to: ASA-CSSA-SSSA Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: November 11, 2002
Publication Date: August 20, 2002
Citation: GITZ, D.C., RITCHIE, J.C., KRIZEK, D.T., BAKER, J.T., REDDY, V.R. 2002 [ABSTRACT]. 2002 ANNUAL MEETING OF THE AMERICAN SOCIETY OF AGRONOMY ABSTRACTS [[CD-ROM]. A03-GITZ133920-POSTER.
Eastern gamagrass [Tripsacum dactyloides (L.) L.] was grown in
large 1 m3 bins on a sand:vermiculite mix with regular
application of a complete nutrient solution in closed sunlit
chambers (Soil Plant Atmosphere Research (SPAR) chambers) at 370
or 740 umol mol-1 CO2 and 20/14°, 27.5/21.5° or 35/29° day/night
temperatures. Plants were allowed to develop from mid-May to
mid-October. Leaf and canopy photosynthesis were 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 increased quantum
use efficiencies (as Fv/Fm and CO2 assimilation vs PAR). In
plants grown at lowest temperature the maximum rate of carbon
assimilation was reached at relatively low PAR flux densities
(1500 umol m-2 s-1 PAR) as compared to high temperature plants
(2500 umol m-2 s-1). We found no conclusive evidence of a CO2
effect on carbon assimilation in these plants.