Effects of Arbuscular Mycorrhizal Fungi on the Ontogeny of Plants (2010)

Undergraduates: Juan Calderon, Megan Rua and Miranda Welsh

Faculty Advisor: Charles Mitchell
Department: Biology

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In this experiment I tested the effects of arbuscular mycorrhizal fungi (AMF) on the ontogeny of plants. AMF provide nutrients to plants in exchange for carbon (energy). We used Koeleria macrantha (Km), Elymus glaucus (Eg) and Bromus carinatus (Bc), matched with annual species Avena fatua (Af), Taeniatherum caput-medusae (Tc) and Bromus hordeaceus (Bh) for this experiment. The plants were grown in the greenhouse. Host nutrition was manipulated indirectly by altering arbuscular mycorrhizal fungi (AMF) which changes plant phosphorous content. We predicted that AMF would reduce allocation to root biomass to allow plants to balance carbon acquisition (in shoots) with carbon transferred to AMF (in roots). We predicted that this effect would be stronger on young plants that have had less time to accumulate carbon stores. The effects of AMF on allocation were consistent across plant species. As predicted, old plants with AMF allocated more biomass to root growth, relative to young plants. This may allow them to absorb more nutrients from the soil.