Item – Theses Canada

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OCLC number
1117498101
Link(s) to full text
LAC copy
Author
Chen, Jinglin,
Title
Characterizing the root-associated microbial community structure after 5 years of phytoremediation on gold mine waste rock in Northern Quebec
Degree
M. Sc. -- McGill University, 2019
Publisher
[Montreal] : McGill University Libraries, [2019]
Description
1 online resource
Notes
Thesis supervisor: Charles William Greer (Internal/Supervisor).
Thesis supervisor: Lyle Whyte (Internal/Cosupervisor2).
Includes bibliographical references.
Abstract
"Gold mining activities have created numerous environmental problems on mined lands, which have become a growing concern to local communities and regulatory authorities. In recent years, plant-microbe mutualistic interactions have been widely applied in cost-effectively reclaiming mine sites with minor contamination, for restoring the soil's sustainability and productivity. Since post-mining soil is nutrient-deficient for plant colonization, hardy native plants such as alders (Alnus spp.) and boreal conifers that naturally form actinorhizal (e.g., Frankia spp.) and mycorrhizal symbioses are often chosen for improving phytoremediation effectiveness. In the current project, we studied a phytoremediation field trial on a gold mine waste rock pile, at Val-d'Or, QC, since 2012. The plantation consists of two alder species, green alder (Alnus viridis subsp. crispa) and speckled alder (Alnus incana subsp. rugosa), and two conifers, white spruce (Picea glauca) and jack pine (Pinus banksiana). Before mine transplantation, alders were greenhouse-inoculated with Frankia sp. strain AvcI1 alone and in combination with mycorrhizal fungal species, Glomus irregulare and Alpova diplophloeus; while white spruce was inoculated with Hebeloma crustiliniforme and Paxillus involutus, and jack pine was inoculated with Suillus tomentosus and Laccaria bicolor. After 5 years of growth in the field, the community structure (diversity and composition) of microbiota living in the plant's rhizosphere and inside roots (i.e., endophytes) was characterized using amplicon sequencing, which targeted the 16S rRNA gene and the nuclear ribosomal internal transcribed spacer (ITS) region for exploring the bacterial/archaeal and fungal communities, respectively, in the environment. On the basis of field observations and measurements, we found that neither inoculation of alders with Frankia nor the dual inoculation with Frankia and mycorrhizal fungi improved alder performance in the mine. In the conifer trial, only the inoculated jack pine had higher survival rates (in 2017) and significantly larger seedling growth compared to the uninoculated seedlings. Amplicon sequencing results revealed that the microbial diversity in both rhizosphere and root compartments did not necessarily increase with inoculation. As for the microbial community composition, except for the jack pine plants inoculated with the ectomycorrhizal (ECM) fungal species Suillus (S. tomentosus) and Laccaria (L. bicolor), no contrasting difference was found between the inoculated and uninoculated (control) plants. In the rhizosphere and bulk soils of the inoculated jack pine plants, we found a higher relative abundance of the bacterial families Acetobacteraceae and Sphingomonadaceae compared to their dominance in the control plants, whereas inside roots, we found the family Acidobacteriaceae (Subgroup 1) was much more abundant in inoculated plants compared to its relative abundance in control plants. In addition, a Suillus fungal genus, which is suspected to be our inoculum S. tomentosus, was found dominating the fungal communities in the inoculated jack pine's rhizosphere, bulk soils and roots, whereas this genus was absent from the control plants. This finding may explain the promoted growth of the inoculated jack pine plants. Regardless of inoculation effects, the planted soils in general improved soil characteristics of the mine leading to a neutral soil pH (7.0), higher moisture content, and a much higher microbial relative abundance."--
Other link(s)
digitool.Library.McGill.CA
escholarship.mcgill.ca
escholarship.mcgill.ca
Subject
Natural Resource Sciences