Arbuscular mycorrhizas in a tropical coastal dune system in Yucatan, Mexico

The main goal of this work was to determine the presence of arbuscular mycorrhizas in coastal dunes of Sisal, Mexico, and the seasonal and spatial changes in the arbuscular mycorrhizal fungal (AMF) community. The study was conducted at three coastal dune zones: embryonic, mobile and stabilized dunes. At each dune zone we chose five dominant plant species, collected roots and determined the percent of mycorrhizal colonization. We also took five soil samples at each dune zone to evaluate AMF spore density and number of infective propagules. The overall AMF colonization ranged from 15 to 19 % depending on the dune zone and the season. The density of spores in 50 g soil was higher during the rainy (11.1 ± 2.6) compared to the dry season (1.55 ± 0.2). AMF were present in root samples of all the plants studied, and infective propagules were present in all dune zones; this held true for both sampling seasons. The presence of viable AMF propagules across the successional vegetation gradient indicates the important role of this interaction on plant survivorship in stressful conditions such as that present in Sisal.