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Genetic Variation in Photosynthesis as a Tool for Finding Principal Routes to Enhancing Photosynthetic Efficiency

Tomeo, Nicholas J.
http://orcid.org/0000-0003-2309-6511
http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1492185865465393

Abstract Details

2017, Doctor of Philosophy (PhD), Ohio University, Plant Biology (Arts and Sciences).
Throughout this dissertation I approach the long-term aim of improving photosynthesis through the lens of natural genetic variation for photosynthesis. To date few studies have directly asked how photosynthetic variation might inform or provide the genetic material required to enhance photosynthesis, despite the clear utility of this strategy for other types of agronomic improvement. Of the many traits underling variation in photosynthesis, mesophyll conductance – the diffusional flux of CO2 through the leaf interior – has potential to improve both photosynthesis and water use efficiency. I assess genetic variation for photosynthesis among ecotypes of the model plant Arabidopsis thaliana and cultivars of soybean (Glycine max). In both species, and across both controlled and field environments in soybean, I find heritable genetic variation for mesophyll conductance that is positively correlated to variation in photosynthetic rate, indicating that selection to enhance mesophyll conductance will increase photosynthesis. Genetic variation in mesophyll conductance though was largely unrelated to variance in water use efficiency as a result of phenotypic correlation between stomatal and mesophyll conductance. If trait variation is to prove useful for crop breeding, that trait must not have already been improved in the varieties currently used by farmers. In soybean, photosynthesis has improved slightly with breeding for yield across a historical set of cultivars. Mesophyll conductance is not responsible for this increase in photosynthesis; it remains unchanged after 75 years of selection for yield. Stomatal conductance is greater in modern varieties and I show that this increase scales from the leaf to the canopy. Greater canopy conductance in modern soybeans resulted in lower canopy temperatures and reduced leaf heat-stress. Few leaf-level photosynthetic traits were improved across this historical set of soybean cultivars. Given that I observed heritable genetic variation for mesophyll conductance among a small sampling of available soybean germplasm, there is substantial opportunity to harness this variation for the improvement of photosynthetic efficiency.
David Rosenthal (Advisor)
Ahmed Faik (Committee Member)
Jared DeForest (Committee Member)
Ryan Fogt (Committee Member)
196 p.
Agronomy; Ecology; Physiology; Plant Biology
Photosynthesis; gas exchange; soybean; crop yield; genetic variation; photorespiration; Arabidopsis thaliana; mesophyll conductance; water use efficiency

Recommended Citations

Citations

  • Tomeo, N. J. (2017). Genetic Variation in Photosynthesis as a Tool for Finding Principal Routes to Enhancing Photosynthetic Efficiency [Doctoral dissertation, Ohio University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1492185865465393

    APA Style (7th edition)

  • Tomeo, Nicholas. Genetic Variation in Photosynthesis as a Tool for Finding Principal Routes to Enhancing Photosynthetic Efficiency. 2017. Ohio University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1492185865465393.

    MLA Style (8th edition)

  • Tomeo, Nicholas. "Genetic Variation in Photosynthesis as a Tool for Finding Principal Routes to Enhancing Photosynthetic Efficiency." Doctoral dissertation, Ohio University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1492185865465393

    Chicago Manual of Style (17th edition)

ohiou1492185865465393
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© 2017, some rights reserved.Creative Commons License Genetic Variation in Photosynthesis as a Tool for Finding Principal Routes to Enhancing Photosynthetic Efficiency by Nicholas J. Tomeo is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by Ohio University and OhioLINK.