Distribution of vesicular-arbuscular mycorrhizae in the plants and rhizosphere soils of the tropical plains,Tamil Nadu,India

We examined 737 plant species from 121 families of angiosperms and four species of pteridophytes for mycorrhizal association. Only 372 species showed infection. Mycorrhizal colonization was recorded in 49% of the total flora. The quantum of colonization ranged from 10% to 90%. In all, 35 species exhibited mycorrhizal colonization higher than 75%. Of the four pteridophytes, Isoetes coromandelina showed mycorrhizal colonization by Entrophospora schenckii and Glomus aggregation in its rhizosphere. For the first time in India, 102 of these species were reported to be mycorrhizal. Glomus fasciculatum (13.8%) and G. aggregation (11%) were prevalent in the rhizosphere soils. Acaulospora foveata (0.2%), A. longula (0.5%) and Glomus hoi (0.9%) were the least represented as mycorrhizal spores. A total of 40 vesicular-arbuscular mycorrhizal fungal species belonging to Acaulospora, Entrophospora, Gigaspora, Glomus, Sclerocystis and Scutellospora were isolated from the rhizosphere soils of different ecosystems.