Date of Award

Fall 12-9-2024

Degree Type

Thesis

Degree Name

Master of Interdisciplinary Studies (MIDS)

Committee Chair

Robert Pal

First Advisor

Alysia Cox

Second Advisor

Daniel Autenreith

Abstract

The microbial community in the rhizosphere of plants plays an important role in plant establishment and survival, soil stability during stormwater runoff, and potential biofiltration of stormwater. Locally adapted fungal symbionts may further improve these outcomes for native plants at restoration sites. This study assesses the potential of host plant cultured, locally adapted soil mycorrhizal inocula to facilitate the establishment and growth of Mountain Big Sagebrush (Artemisia tridentata subsp. vaseyana) on heavy-metal contaminated soils. Soil was obtained from the rhizosphere of native plants at three sites in the West Side Soils Operable Unit of the Butte, Montana Superfund Complex. One sample site contained arsenic-(As) contaminated soil, the second site contained lead-(Pb) contaminated soil, and the third site contained uncontaminated soil and had a diverse native plant population. Inocula were produced from each of these samples using Sorghum as a host plant. Pots were set up containing a mixture of potting soil, sand and either live inoculum or sterilized inoculum. Both inocula production and the plant growth study were maintained in a greenhouse. Plant growth parameters were measured and the system’s biofiltration capabilities with As- or Pb-contaminated simulated stormwater were evaluated. Plant growth parameter results indicate that the live inoculum cultured from the As- contaminated soil was beneficial to plant growth on As-contaminated soil. This trend was not observed with the live inoculum cultured from Pb-contaminated soils. The results obtained with the live As-contaminated inocula suggest that the use of locally adapted mycorrhizal inoculum may help plants establish on heavy metal-contaminated restoration sites. The stormwater simulation was set up in the same pots to assess the potential for biofiltration of contaminated stormwater. The results indicated that effluent from pots containing plants with larger biomass generally contained a lower concentration of contaminants. Our study showed that locally adapted mycorrhizae aid in plant growth, which may aid in the biofiltration of heavy metal-contaminated stormwater in areas like Butte, MT. In addition, the biofilter column set up used here may be useful as a new methodology to increase repetitions in future biofiltration experiments.

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