Arbuscular mycorrhizal fungi associated with Festuca species in the Canadian high arctic

Root and soil samples from 13 collecting sites located in the Canadian High Arctic were harvested between July 18 and 29, 1991, and surveyed for root colonization and spore populations of arbuscular mycorrhizal fungi. Grasses of the genus Festuca (Festuca brachyphylla Schult. & Schult., Festuca baff inensis Polunin, and Festuca hyperborea Holmen ex Frederiksen) served as ta rget plants. Of the 197 plant-root systems and soil rhizospheres examined, 28% were associated with arbuscular mycorrhizae. Roots of both F: brachyphy lla and F: baffinensis were colonized, while none were detected in F. hyper borea root specimens. Five arbuscular mycorrhizal fungal species were extra cted from indigenous soils. The most frequent and abundant species was Glom us mosseae (Nicol. & Gerd.) Gerdemann & Trappe, which was isolated from 8 o f the 13 sites sampled. Other Glomales species in Arctic soils were Glomus macrocarpum Tul & Tul., Glomus fasciculatum (Thaxter sensu Gerd.) Gerd. & T rappe emend. Walker & Koske, and two other unidentified Glomus species. Tra p cultures of the indigenous soil with leek (Allium porrum L.) plants confi rmed the identity of the species previously identified from original soil a nd allowed the detection of an additional species, Glomus aggregatum Schenc k. & Smith. The novelty of these observations and the relationship between plant mycorrhizal status, fungal species, and soil disturbance are discusse d.