Date of Award
2025
Document Type
Open Access Master's Thesis
Degree Name
Master of Science in Biological Sciences (MS)
Administrative Home Department
Department of Biological Sciences
Advisor 1
Erika Hersch-Green
Committee Member 1
Erik Lilleskov
Committee Member 2
Trista Vick-Majors
Abstract
Polyploid and larger genome size plants have been shown to contain more cellular nitrogen and phosphorus than related diploid and smaller genome size plants, indicating they have greater nutrient requirements. Given that arbuscular mycorrhizal fungi (AMF) associations can enhance plant nutrient acquisition, polyploid and larger genome size plants may form more associations with AMF to meet their increased nutrient demands and gain greater benefits from these symbioses. However, because AMF associations become unnecessary when nutrient-rich soils meet plant needs independently, these interactions may be more likely to occur under nutrient-poor conditions. For this research, we conducted two experiments to examine how polyploidy, genome size, and nutrient enrichments influence plant responses to AMF and AMF root colonization patterns. In the first experiment, we grew diploid and polyploid Chamerion angustifolium under a full factorial combination of ambient or enriched nutrients and AMF presence or absence, and measured traits related to plant performance, resource-use, and AMF root colonization. We hypothesized that polyploids would exhibit greater AMF root colonization and gain more performance and resource-use benefits than diploids under ambient nutrients, but that differences in AMF root colonization and responses between diploids and polyploids would be reduced under enriched nutrients. Contrary to our predictions, we found that diploids exhibited greater performance and resource-use responses to AMF than polyploids under ambient nutrients, and that polyploids had higher AMF root colonization rates across both nutrient treatments. We found that neither cytotype benefitted significantly from AMF under high nutrients. In the second experiment, we sampled a grassland community with a range in genome sizes from both control and nutrient-enriched plots to test the hypothesis that AMF root colonization increases with genome size in ambient nutrient conditions and is less affected by genome size in nutrient-enriched conditions. We found that the influence of genome size was minimal, and that nutrient enrichment decreased AMF root colonization. Our findings highlight that genome size and polyploidy can have complex effects on plant-AMF interactions, and that these effects are further mediated by nutrient availability. This research provide greater insight into the role that polyploidy and genome size play in plant-AMF dynamics, an increasing crucial goal as shifts in nutrient availabilities worldwide are altering primary producer and multitrophic communities.
Recommended Citation
Blackwell, Abbigail J., "EXAMINING THE ROLE OF PLANT GENOME SIZE AND POLYPLOIDY IN SHAPING ARBUSCULAR MYCORRHIZAL FUNGI SYMBIOSES", Open Access Master's Thesis, Michigan Technological University, 2025.