Thesis
Efficiency of the CO2-concentrating mechanism in single-cell C4 photosynthesis
Washington State University
Master of Science (MS), Washington State University
2010
Handle:
https://hdl.handle.net/2376/100113
Abstract
The availability of atmospheric CO2 limits rates of photosynthesis and leads to increased photorespiration, particularly when stress induces stomatal closure. In response, some plants evolved a CO2-concentrating mechanism termed C4 photosynthesis, which concentrates CO2 around Rubisco and reduces rates of photorespiration. C4 photosynthesis was previously thought to require a dual-cell (Kranz-type) anatomy to prevent diffusional CO2 loss, or "leakiness," from the leaf. However, two C4 photosynthetic pathways using dimorphic chloroplasts within single cells were recently discovered in the Chenopodiaceae family. Bienertioid anatomy concentrates CO2 across peripheral and central cytoplasmic compartments (Bienertia sinuspersici), while Borszczowoid anatomy utilizes distal and proximal compartments (Suaeda aralocaspica). C4 photosynthesis within an anatomically simpler package of a single-cell versus Kranz anatomy raises physiological questions and has potential for engineering C4 traits into C3 crops. This project aims to characterize the CO2-concentrating mechanism efficiency in two subtypes of single-cell C4. The efficiency of the CO2-concentrating mechanism was estimated from leaf level measurements of photosynthetic carbon isotope discrimination under various temperature and light conditions. Here we present data showing similar levels of total photosynthetic isotope discrimination and rates of CO2 leakiness in both forms of single-cell compared to the Kranz type C4 species. Temperature manipulations did not significantly alter the similarity between the single-cell and Kranz-types, while decreasing light availability increased photosynthetic isotope discrimination and leakiness across all C4 types. Our data demonstrate that the rates of photosynthesis and efficiency of the CO2-concentrating mechanisms in single-cell C4 are similar to those of the Kranz-type.
Metrics
2 File views/ downloads
16 Record Views
Details
- Title
- Efficiency of the CO2-concentrating mechanism in single-cell C4 photosynthesis
- Creators
- Jenny L. King
- Contributors
- Asaph B. Cousins (Degree Supervisor)
- 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, Wash. :
- Identifiers
- 99900524858901842
- Language
- English
- Resource Type
- Thesis