Sudderth, Erika, A , Holbrook, Noel .
Respnse of C3, C4, and intermediate Flaveria species to elevated CO2 and temperature.
Numerous studies have shown positive responses of C4 species to elevated CO2, primarily due to increased water use efficiency under dry growth conditions. However, the effects of elevated CO2 and temperature on C4 dicots species has only been examined in a few studies. Extensive research on the CO2 response of C3 species has shown that dicots generally show larger increases in biomass accumulation in response to elevated CO2 than monocots. We compared the effects of elevated CO2 and increased temperature on biomass accumulation, photosynthesis responses, and chlorophyll fluorescence in four dicot species in the genus Flaveria that utilize different photosynthetic cycles. We found stronger responses to elevated CO2 than expected under well-watered conditions in the C4 species F. trinervia. The treatments did not affect leaf nitrogen content or photosynthesis rates of F. trinervia but leaf area, above ground biomass, and WUE increased under elevated CO2, suggesting lower rates of water loss for a given photosynthetic rate. The other C4 species, F. kochiana, grew very slowly and showed little response to the environmental treatments. Elevated CO2 increased the above ground biomass of the intermediate species, F. ramosissima but increased temperature greatly reduced plant biomass. In the C3 F. pringlei, biomass accumulation increased in response to elevated CO2 but growth was not reduced under high temperatures as predicted. This result indicates that F. pringlei has a high capacity to acclimate and perform well under different growth conditions, a result supported by field observations that F. pringlei grows in a wide variety of habitat types. There were species level correlations between leaf nitrogen content, photosynthetic rate, and biomass accumulation but these relationships were not consistent between different environmental treatments.
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Thesis research description
1 - University of California, Berkeley, Integrative Biology, 3060 Valley Life Sciences Building, Berkeley, CA, 94720-3140, USA
2 - Harvard University, Department of Organismic and Evolutionary Biology, 16 Divinity Ave, Cambridge, MA, 02138, USA
Presentation Type: Oral Paper:Papers for Topics
Date: Monday, July 28th, 2008
Time: 4:15 PM