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Climate Change Affects Leaf Morphology: Investigating Mechanism and Variation Across Species

Thomas, Michael D
http://orcid.org/0000-0002-7355-9302
http://rave.ohiolink.edu/etdc/view?acc_num=toledo16516825891515

Abstract Details

2022, Master of Science, University of Toledo, Biology (Ecology).
Atmospheric carbon dioxide (CO2) concentrations are increasing and may exceed 800 ppm by 2100. This is increasing global mean temperatures and the frequency and severity of heatwaves. Recently, it was shown for the first time that the combination of chronic warming and elevated carbon dioxide (eCO2) caused extreme upward bending during growth (i.e., hyponasty) of leaflets and leaf stems (petioles) in tomato (Solanum lycopersicum), which reduced growth. However, that study examined only two levels of CO2 (400, 700 ppm) and temperature (30, 37oC) at the young vegetative plant stage. Further, they did not investigate underlying mechanisms for this warming + eCO2-induced hyponasty, which is likely to involve the plant hormones auxin and ethylene, based on their role in thermal hyponasty. In this study, warming + eCO2 hyponasty was evaluated in tomato across a range of temperatures and CO2 concentrations, and at multiple life stages. Ethylene tomato mutants were examined to explore the potential role of these hormones in warming + eCO2 hyponasty. Lastly, other species were examined to test the hypothesis that warming + eCO2 hyponasty is restricted to compound-leaved species in this family. At eCO2 (800 ppm), petiole angle increased ca. linearly as temperature increased from 30-38oC. Under heat stress (HS, 38°C), petiole angle increased at all eCO2 concentrations compared to ambient (600/800/1000 vs. 400 ppm). All life stages examined (juvenile, pre-reproductive, and flowering) had increased petiole angle in leaves developed during warming + eCO2, such that most leaves exhibited hyponasty in juvenile plants but only young leaves did so in adults (previously fully-developed leaves were unaffected). Ethylene-insensitive (nr) and -constitutive (epi) mutants displayed similar changes in petiole angle with warming + eCO2 compared to the non-mutant reference (cv. Celebrity), indicating that ethylene is not a main component of the mechanism of this hyponastic response. Auxin-insensitive (dgt) mutants did not display changes in petiole angle with warming + eCO2 compared to the non-mutant reference (cv. Celebrity) and auxin-constitutive mutant (e) exhibited increased hyponasty, indicating that auxin is involved in this hyponastic response. Only compound-leaved Solanaceous species exhibited warming + eCO2 hyponasty, though responses outside of Solanaceae were variable. Warming + eCO2 hyponasty may have negative consequences for the productivity of certain wild and domesticated agronomic species in the coming decades, and understanding the underlying mechanisms of this response may prove useful for developing resistant crops.
Scott Heckathorn, Dr. (Committee Chair)
Heidi Appel, Dr. (Committee Member)
Jennifer Boldt, Dr. (Committee Member)
49 p.
Agriculture; Agronomy; Biology; Botany; Climate Change; Ecology; Environmental Science; Forestry; Morphology; Physiology; Plant Biology; Plant Sciences
Climate Change; eCO2; Warming; Global Warming; Leaf Angle; Hyponasty; Heat stress; Leaf Morphology; Tomato; Solanum lycopersicum; Plants; CO2; Carbon Dioxide; Auxin; Ethylene; Phytochrome; PhyB; Thermomorphogenesis; Shade avoidance Strategy; Morphology;

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Citations

  • Thomas, M. D. (2022). Climate Change Affects Leaf Morphology: Investigating Mechanism and Variation Across Species [Master's thesis, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo16516825891515

    APA Style (7th edition)

  • Thomas, Michael. Climate Change Affects Leaf Morphology: Investigating Mechanism and Variation Across Species. 2022. University of Toledo, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo16516825891515.

    MLA Style (8th edition)

  • Thomas, Michael. "Climate Change Affects Leaf Morphology: Investigating Mechanism and Variation Across Species." Master's thesis, University of Toledo, 2022. http://rave.ohiolink.edu/etdc/view?acc_num=toledo16516825891515

    Chicago Manual of Style (17th edition)

toledo16516825891515
168
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This open access ETD is published by University of Toledo and OhioLINK.