Role of nutrient level and defoliation on symbiotic function: experimental evidence by tracing C-14/N-15 exchange in mycorrhizal birch seedlings
High nutrient availability and defoliation generally reduce ectomycorrhizal colonization levels in trees, but it is not known how this affects the functional aspects of mycorrhizal symbiosis. It was therefore investigated whether (1) defoliation or increasing substrate N availability reduce C allocation from the plant to the fungus and N allocation from the fungus to the plant (symbiotic resource