Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 6, 2003
Publication Date: November 6, 2003
Citation: JOHNSON, J.M-F., GESCH, R.W., BARBOUR, N.W. CONTRASTING TEMPERATURE REGIMES ALTER COMPOSITION AND PHENOLOGY OF SWITCHGRASS AND WHEAT. CD-ROM. MADISON, WI: ASA-CSSA-SSSA. 2003. Technical Abstract: Global temperatures are expected to rise 2-6 deg C within this century. Temperatures greatly affect how plants partition photosynthates among plant organs. The objective of this study was to compare structural and nonstructural carbohydrate partitioning between a C3 and C4 grass at two temperature regimes. Switchgrass (C4; Panicum virgatum L.) and wheat (C3; Triticum aestivum L.) were grown under 18/24 and 27/33 deg C night/day temperature regimes. Phenological data was collected (plant height, leaf area, tiller number, biomass) and plant material sampled at four leaf and preanthesis. Concentrations of nonstructural and structural carbohydrates, and lignin were determined for shoots and roots. For switchgrass, shoot and root biomass, tillering, and leaf area increased with growth temperature while wheat growth declined dramatically. Starch concentration was about three-times lower in leaves and stems of switchgrass and 2 to 8-times lower in leaves and stems of wheat grown at 27/33 deg C n/d compared to plants grown at 18/24 deg C n/d. Total lignin produced per plant increased at 27/33 deg C temperatures in switchgrass, but was dramatically decreased in wheat compared to 18/24 deg C. These differences reflect both changes in lignin concentration and biomass production.