Thesis
Growth of the single-cell C₄ plant, Bienertia sinuspersici, under light-limited conditions
Washington State University
Master of Science (MS), Washington State University
2012
Handle:
https://hdl.handle.net/2376/103762
Abstract
Generally, C4 photosynthesis requires two cell types (Kranz-anatomy) to concentrate CO2 within the leaf. However, several species have been identified that lack Kranz-anatomy and perform C4 photosynthesis using dimorphic chloroplasts within an individual cell. In both Kranz-type and single-cell C4 plants some of the concentrated CO2 around Rubisco leaks out of the leaf (leakiness), reducing photosynthetic efficiency. In single-cell C4 plants the distance between dimorphic chloroplasts is predicted to affect the resistance of CO2 diffusion and therefore leakiness. When grown under optimal growth conditions the single-cell C4 plants have similar photosynthetic efficiencies compared with Kranz-type plants, but it is not known how growth under limited light affects the leaf structure and efficiency of the single-cell CO2 concentrating mechanism. The single-cell C4 plant, Bienertia sinuspersici, was grown under medium- and low-light, and measurements of leaf CO2 isotope exchange in response to irradiance, and O2 concentrations were used to determine how the efficiency of the single-cell CO2 concentrating mechanism changes in response to growth light conditions. Additionally, enzyme assays, chlorophyll content and light microscopy were used to further determine how B. sinuspersici responds to light-limited growth conditions. Photosynthetic enzyme activity and the specific leaf areas were higher in medium-light compared to low-light plants. Chlorophyll content and leaf thickness did not change significantly between light treatments. Photosynthesis and respiration rates were higher in medium-light compared to low-light plants but photosynthetic carbon isotope discrimination was similar in medium- and low-light plants under high irradiance measurement conditions and 21% O2. However, photosynthesis decreased with increasing O2 concentration for both mediumand low-light plants. Additionally, carbon isotope discrimination increased with O2 concentration under both light treatments but more so in the low-light plants. In general, it appears that the low-light growth conditions decreased the efficiency of the CO2 concentrating mechanism, particularly in response to changing O2 concentrations, in the single-cell C4 plant B. sinuspersici.
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Details
- Title
- Growth of the single-cell C₄ plant, Bienertia sinuspersici, under light-limited conditions
- Creators
- Samantha S. Stutz
- Contributors
- Asaph B Cousins (Chair) - Washington State University, Biological Sciences, School ofGerald E Edwards (Committee Member) - Washington State University, Biological Sciences, School ofR Alan Black (Committee Member) - Washington State University, Biological Sciences, School of
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Sciences, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525064901842
- Language
- English
- Resource Type
- Thesis