Distribution of three endangered medicinal plant species and their colonization with arbuscular mycorrhizal fungi

A field study of 12 districts of arid zones of Rajasthan was undertaken to evaluate the occurrence of three selected endangered medicinal plant species (Leptadenia reticulata, Mitragyna parvifolia, Withania coagulans), and arbuscular mycorrhizal fungal (AMF) associations with them. Five genera were identified in the rhizosphere of these selected plant species. A high diversity of AMF was observed which varied between different host plant species. Among the five genera, Glomus occurred most frequently, with ten species, Acaulospora and Scutellospora were found with three species, respectively, while Gigaspora and Paraglomus were detected with one species each. Glomus constrictum, Glomus fasciculatum, Glomus geosporum, Glomus intraradices, Glomus mosseae and Glomus rubiforme were the most dominant species. The AMF spore density was not clearly affected by the host plant suggesting that biotic factors may be relatively less important than abiotic/edaphic factors for establishing population pattern. The spore density of AMF had a strong positive correlation with soil pH and organic carbon content and a negative correlation with Olsenʹs P content of the soil. The association with AMF of these plant species native to the harsh environmental conditions of the Indian Thar Desert may play a significant role in the re-establishment and conservation of these multipurpose endangered medicinal plants.