XVI International Botanical Congess

We studied arbuscular mycorrhizal (AM) associations in long-term N fertilization experiments in MI, MN, KS, CO, and NM grasslands. We also studied impacts of N-enrichment on AM functioning by examining responses of native grasses inoculated with soils from fertilized and unfertilized field plots. N fertilization generally reduces AM fungal biomass, except at the KS site, where the response is reversed. Spore communities are also impacted by N, members of the Gigasporaceae are generally less abundant in N-enriched sites compared to control sites. Again, the response is reversed at the KS site. Our results indicate that N-enrichment impacts AM functioning. At three of the sites, ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ