Seasonal variations of arbuscular mycorrhizal fungal association with Ipomoea pes-caprae of coastal sand dunes, Southern India

Two years seasonal studies on arbuscular mycorrhizal (AM) fungi associated with Ipomea pes-caprae established on the coastal sand dunes of the west coast of india yielded 41 species belonging to six genera. The percent root colonization by the AM fungi was least during monsoon (28.7-64.6%) and highest during post-monsoon (80.6-93.6%), but the mean spore density in rhizosphere was least during post-monsoon (9.5-35/100 g) and highest during summer season (58.2-132.5/100 g). The species belonging to the genus Glomus were most common (51%). Colonization of roots was strongly correlated with the rhizosphere moisture, pH, organic carbon, calcium, sodium, potassium, nitrogen and phosphate (p > c.v.), whereas only organic carbon, calcium and phosphate showed significant correlation (p > c.v.) with species richness and spore density. The high levels of colonization, spore density, species richness and correspondence of AM fungal phenology with host plant phenology might have increased the fitness of Ipomoea pes-caprae for successful establishment on the sand dunes of west coast of India.