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ENVIRONMENTALLY ACQUIRED RESISTANCE: ARSENIC AFFECTING NATURAL SELECTION ON PLANT DEFENSES AND COMPETITIVE ABILITY

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dc.contributor.authorRuesch, Joseph MacKenzie
dc.contributor.chairSchroeder, Frank
dc.contributor.committeeMemberKessler, Andre
dc.contributor.committeeMemberSacks, Gavin Lavi
dc.date.accessioned2022-09-15T15:51:22Z
dc.date.available2022-09-15T15:51:22Z
dc.date.issued2022-05
dc.description105 pages
dc.description.abstractEnvironmental toxins, such as toxic metals and metalloids, can affect basic life functions in fundamentally different organisms and so affect the outcome of ecological interactions, community, and ecosystem dynamics. For example, some metalloids, such as arsenic (As) can affect both the physiology of primary producers (e.g. plants) as well as that of their consumers (e.g. herbivores). In plant-insect interactions, As can affect the outcome of the interaction in two ways: through plant sequestration of As from the environment and thus exposure of consumer guilds to the toxin, or through As-induced stress responses that affect defense-related plant secondary metabolite production and so the plant’s resistance to herbivores. In this thesis, I test the hypothesis that As, sequestered by plants from the surrounding soil, functions as an environmentally acquired resistance and thus affects the plants’ evolution of plant endogenous chemical defenses. Studies included a survey on a field containing a natural gradient of As contamination, and experiments measuring the response to natural selection by putting plants from different As environments into common gardens and measuring plant chemical defense traits, competitive ability, and elemental composition. In support of the environmentally acquired resistance hypothesis, plants grown on high-As contaminated soils receive less damage than plants on low-As soils and have increased plant defensive compound production. It is also seen that high-As genotypes, when removed from As, show increased growth and competitive ability, while having decreased endogenous chemical defenses. This suggests that herbivory differentially selected on plant defense and competitive ability as a function of the spatial distribution of soil As concentrations in the landscape. This selection has resulted in a reduction of endogenous defense traits and a reallocation of resources into increased competitive ability. Finally, elemental analysis discovered a high-As genotypic increase in As/Phosphorus uptake ratio that implies a selection for increased environmentally acquired resistance. Based on these findings, it can be extrapolated that any environmental contaminant that can affect plant resistance and functions as an environmentally acquired resistance trait can potentially affect the evolution of plant endogenous resistance and thus contribute to the spatial genetic structure of populations as well as community dynamics.
dc.identifier.doihttps://doi.org/10.7298/z68q-f777
dc.identifier.otherRuesch_cornellgrad_0058F_12918
dc.identifier.otherhttp://dissertations.umi.com/cornellgrad:12918
dc.identifier.urihttps://hdl.handle.net/1813/111781
dc.language.isoen
dc.subjectArsenic
dc.subjectDiterpenoids
dc.subjectEICA
dc.subjectPlant defenses
dc.subjectResistance
dc.subjectTolerance
dc.titleENVIRONMENTALLY ACQUIRED RESISTANCE: ARSENIC AFFECTING NATURAL SELECTION ON PLANT DEFENSES AND COMPETITIVE ABILITY
dc.typedissertation or thesis
dcterms.licensehttps://hdl.handle.net/1813/59810.2
thesis.degree.disciplineChemistry and Chemical Biology
thesis.degree.grantorCornell University
thesis.degree.levelDoctor of Philosophy
thesis.degree.namePh. D., Chemistry and Chemical Biology

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