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Fungal endophyte infection in an alpine meadow: testing the mutualism theory

Neotyphodium are fungal endosymbionts of grasses that reproduce asexually by infecting the hosts seed. This relationship has traditionally been considered mutualistic, with the fungus improving host fitness by alleviating important stresses. To determine the importance of biotic and abiotic stresses in mediating the endophyte-grass interaction, I investigated the relationship between grazing pressure by collared pikas and Neotyphodium sp. infection frequency in the grass Festuca altaica in an alpine meadow. I conducted a factorial design experiment combining endophyte infection, grazing history, fungicide and fertilizer. Leaf demography and herbivory damage were monitored every two weeks. In areas with chronic grazing history, infected plants were significantly less productive than uninfected tussocks, but there was no difference at low grazing history. There was no effect of infection on the likelihood of herbivory. Contrary to predictions of the mutualism theory, the Neotyphodium sp. / F. altaica symbiotum varied from parasitic to neutral across our gradient of interest. / Ecology

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:AEU.10048/1248
Date11 1900
CreatorsCardou, Franoise
ContributorsHik, David S. (Biological Sciences), Currah, Randolph S. (Biological Sciences), Vinebrooke, Rolf (Biological Sciences), Bork, Edward (Agricultural, Food and Nutritional Sciences)
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
LanguageEnglish
Detected LanguageEnglish
TypeThesis
Format893496 bytes, application/pdf

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