Arbuscular Mycorrhizae of Gymnacranthera faquhariana (Hook. F. & Thomson) Warb. in Ex-situ and In-situ Conditions

The arbuscular mycorrhizal (AM) population of one year old seedlings of Gymnacranthera farquhariana was studied both under in-situ conditions in a Myristica swamp of evergreen forests of the Uttara Kannada, Karnataka and ex-situ condition in the Arboretum of the Deptt. of Applied Botany, Mangalore University. The soil and ischolar_main samples from the rhizosphere region were examined season-wise over a period of two years during 1995-1996 for AM species diversity, spore density and colonization pattern from both the locations. The moisture content, temperature, pH, organic matter content and mineral elements of the soils of both the locations were estimated. There was season-wise variations in the soil moisture, temperature, N, P, K, Ca, Cu, Fe, Mg and Zn contents in both the locations. Altogether 29 species of AM fungi belonging to six genera were isolated in this study. Of these, 19 species were from Myristica swamps and 23 species from the Arboretum. Among them, 13 species were common to both the locations. The six species observed in the rhizosphere of seedlings in Myristica swamp were not found in the Arboretum. Similarly, the 10 species observed in the rhizosphere of seedlings of Arboretum were not found in the swamp. Sorensen's similarity index showed 61.9% similarity among the AM flora between the two locations. Glomus was found to be the dominant genus in both the locations. Season-wise, maximum spore density was observed in July (monsoon) samplings and minimum in March (summer) samplings and ischolar_main colonization was maximum in November (post-monsoon) and minimum in March (summer) in both the locations. The variations in the spore density and ischolar_main colonization were correlated with physico-chemical properties of the rhizosphere soils.