Abstract: Ginkgo biloba is a unique relict tree species in China, whose root system can form a mutually beneficial mycorrhizal system with arbuscular mycorrhizal fungi (AM fungi). To determine the dominant indigenous AM fungi in the rhizosphere of ancient G. biloba in Shanghai, root and soil samples from ancient (about 200 years old) and adult G. biloba (about 50 years old) were collected. The infection characteristics of AM fungi in roots were determined by acetic acid ink staining with subsequent microscopic examination. The classification of genus and species and dominance analysis was carried out using morphological and molecular identification methods. The results showed that the structure of AM fungal community of roots were of intermediate type (Type I). The mycorrhizal infection rate of root system of ancient G. biloba (41.1%) was significantly lower than that of adult G. biloba (60.0%). Furthermore, 20 AM fungi species were isolated from the rhizosphere soil of ancient G. biloba, of which 8 genera and 13 species were identified morphologically. Through induced cultivation, four dominant species were obtained. Three out of the four species were molecularly identified as Claroideoglomus claroideum, Funneliformis mosseae, and Septoglomus viscosum. Our results provide a basis for promoting the application of locally dominant indigenous AM fungi of ancient G. biloba in environmental conservation, plant growth promotion and the rejuvenation of ancient trees.

Key words: ancient Ginkgo biloba, indigenous AM fungi, community diversity