|Kim, Soo hyung|
Submitted to: ASA-CSSA-SSSA Proceedings
Publication Type: Abstract only
Publication Acceptance Date: 11/2/2003
Publication Date: 11/2/2003
Citation: Kim, S., Bae, H., Gitz, D.C., Sicher Jr, R.C., Baker, J.T., Timlin, D.J., Reddy, V. 2003. Responses of maize to elevated carbon dioxide: from gene expression to whole-plants [abstract]. ASA-CSSA-SSSA Proceedings. Poster No. 815. Interpretive Summary:
Technical Abstract: Studies have shown that some C4 plants can accumulate more biomass under elevated CO2, whereas the underlying mechanisms of this response are unclear. Photosynthetic, growth and developmental responses of maize plants to elevated CO2 were investigated using molecular, biochemical, and leaf and whole-plant methodologies. This was done in order to test the hypothesis that elevated CO2 alters expression of genes, enzyme activities, leaf and whole-plant gas exchange, and biomass accumulation. Corn plants were grown in six naturally lit Soil-Plant-Atmosphere-Research (SPAR) chambers in Beltsville, MD. Each chamber was assigned randomly to receive either ambient (370 ppm) or elevated (750 ppm) CO2. Leaf and whole-plants gas exchange properties including rates of CO2 assimilation, transpiration, and conductance to water vapor were investigated. Activities of photosynthetic enzymes involved in the C4 cycle were measured. Global changes and patterns of gene expression were compared using DNA microarrays. Total carbon and nitrogen content, and biomass accumulation were investigated. The results indicated that elevated CO2 did not alter biomass, leaf area, leaf and whole-plant CO2 assimilation rates, or the measured C4 enzyme activities. Elevated CO2 did result in decreased leaf and whole-plant transpiration rates; reduced conductance to water vapor; increased water use efficiency; and a higher leaf C/N ratio. Several genes were found to show different levels of expression in response to elevated CO2.