Semester
Summer
Date of Graduation
2023
Document Type
Thesis
Degree Type
MS
College
Eberly College of Arts and Sciences
Department
Biology
Committee Chair
Jennifer Hawkins
Committee Co-Chair
Jonathan Cumming
Committee Member
Stephen DiFazio
Abstract
Under the threat of climate change with continued fossil fuel use, investment in developing renewable energies is increasingly important. One category of renewable energy sources, biofuels, is well suited to industries that require a liquid fuel source. However, producing biofuel feedstocks is challenging from a sustainability perspective, as they require extensive land area and resource input to grow on marginal lands. The identification of strategies that feedstock species use to maintain productivity with limited to no resource inputs could aid in the selection of optimal genotypes or targets of breeding or engineering efforts to maximize productivity in feedstock plantations. Some of these targets may be belowground traits, which have not been extensively studied. Therefore, this research sought to uncover and compare the aboveground and belowground strategies used by two Populus trichocarpa genotypes differing in their tolerance to water deficit stress in response to drying. Trees were subjected to gradual drying to wilt point followed by three weeks of consistent stress. Aboveand belowground morphology and physiology were measured at wilt point and at the end of the experiment, and the leaf and root transcriptomes were sequenced to provide insight into the metabolic mechanisms underlying responses to water deficit stress. The tolerant genotype kept its stomata partially open under stress, allowing more water loss via transpiration but also enabling carbon uptake. It compensated for continued water loss by devoting resources to root growth for soil exploration for water, particularly using finer roots. The balance of resource use and acquisition likely allowed for better maintenance of productivity during stress. At the transcriptional level, jasmonate signaling pathways, which cause similar morphological and physiological changes in other species, were upregulated in the tolerant genotype. Results of this study suggest that root characteristics that promote water uptake from a limited pool of resources can allow for continued gas exchange under stress, which has been previously identified as a sign of sensitivity, to promote drought tolerance. Additionally, a need to investigate the role of jasmonate signaling in drought tolerance in poplar as a potential target of feedstock improvement is revealed.
Recommended Citation
Ratliff, Kristin Justine, "Morphological, physiological, and transcriptional responses of Populus trichocarpa to water deficit stress" (2023). Graduate Theses, Dissertations, and Problem Reports. 12141.
https://researchrepository.wvu.edu/etd/12141