Fungal endophytes, grasses and competition: An experimental and field approach

Fungal endophytes occur in most plant species studied to date. In the grass family, Poaceae, symptomless fungal endophytes are generally considered to be plant mutualists. A large body of research on a small number of agricultural grasses shows that endophytes can reduce herbivory and increase the competitive ability of their host grass. In contrast, some studies have failed to demonstrate a benefit for infected species leading to suggestions that there is a gradient of interactions ranging from the being beneficial to parasitic depending on the ecological conditions. Most of the research into grass-endophyte interactions has been carried out in North American agricultural systems, where intense herbivory provides a strong selective factor favouring the survival and spread of infected plants. The objective of my research was to determine whether endophytes increase their host grass competitive abilities in European grasslands, specifically Sweden in absence of strong herbivory. I carried out a field-based study and a greenhouse-based intra-specific competition experiment with Festuca rubra plants collected from Swedish seed sources. (Abstract shortened by UMI.)...