Little Halophyte on the Prairie: Canadian Salt-Tolerant Plants as Remediation Tools for Salinized Soils in Western Canada
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Authors
Kraemer, Emily
Date
Type
thesis
Language
eng
Keyword
Soil salinization , Halophyte , Remediation , Salinity tolerance , Chloride , Sulphate
Alternative Title
Abstract
In western Canada’s prairies, secondary soil salinization is contributing to groundwater contamination, soil degradation, and plant toxicity. To remediate salt-contaminated sites, a non-invasive, resource-efficient method is required. Phytoremediation with salt-tolerant plants (halophytes) is a strong alternative to conventional site clean-up methods, as plants will continuously extract salts from soil whilst improving soil structure. Three native (Bouteloua gracilis, Bouteloua curtipendula, Distichlis spicata) and three naturalized (Puccinellia distans, Atriplex patula, Chenopodium album) halophytes were grown under controlled greenhouse conditions with salt concentrations of 1500 µg/g Cl- to quantify salt extraction from contaminated soil originating from a legacy site. Based on the results obtained, A. patula, C. album, P. distans, and B. gracilis were further studied under greenhouse conditions at extremely high salt concentrations (10,500 µg/g Cl-) and accumulated 333, 176, 6.49 and 2.43 mg Cl-/shoot DW respectively. Under ideal conditions, it would take the accumulator halophyte species A. patula and P. distans ~1.3 and ~2.4 years, respectively, to remediate the site. Proof-of-concept for phytoremediation studies is needed to validate the method, hence field studies were undertaken with seven halophyte species at the legacy site using raised bed ‘mesocosms’ spiked to 10,500 µg/g Cl-. Halophyte chloride accumulation and biomass production did not significantly differ between an unamended mesocosm and one amended with 30% (by volume) triple mix. Halophyte species accumulated 0.106 – 4.27 mg Cl-/shoot DW in the field, despite climatic extremes, with opportunistic species A. fatua, T. officinale, and C. arvense accumulating even higher quantities (1.44 – 88.8 mg Cl-/shoot DW). Since recretohalophytes demonstrated minimal excretion rates in the greenhouse and the field, all three Bouteloua species, D. spicata, and Sporobolus michauxianus were grown in salt-spiked soil and excreted crystals were imaged using scanning electron microscopy. D. spicata excreted smaller salt crystals at a higher density than the larger salt crystals of S. michauxianus, and on the basis of total surface area D. spicata excreted four times as many crystals. Overall, the results of the studies undertaken indicate that the use of native and/or naturalized accumulator halophytes are justifiable in terms of efficacy to remediate salt-affected legacy sites in western Canada.
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ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.