Mycorrhizae are common plant-fungal symbioses occurring in most land plants. Despite their ubiquity, little is known about the distribution of arbuscular mycorrhizae (AM) in extreme environments. We surveyed for the presence of AM in thermal sites in Yellowstone National Park (YNP) where soils are characterized by extreme pHs, elevated temperatures, and toxic element concentrations. Plants at 5 sites, growing in soils with rooting-zone temperatures up to 48Â°C and soil pH values as low as 3.4, were mycorrhizal (colonization levels from 4% to 34%). Soils from a sparsely vegetated thermal area and an adjacent, continuously vegetated transition area differed significantly in rooting-zone temperature (35Â°C vs. 26Â°C), acidity (pH 3.8 vs. 5.4), electrical conductivity (2.22 vs. 0.49 mmhos cm-1), Fe (181.3 vs. 48.5 mg kg-1),Mn (7.2 vs. 98.2 mg kg-1), and Zn (2.3 vs. 4.5 mg kg-1). Mycorrhizal infectivity potential (MIP) was 77% greater in the transition soils, with colonization levels of 26% and 46% in thermal and transition soils, respectively. Furthermore, colonization of Agrostis scabra, Dichanthelium lanuginosum, and Mimulus guttatus was found to be consistently high throughout the growing season (from 48% to 72%). It is possible that AM are essential for plant life on the edge of thermal areas, and that either or both symbionts are specifically adapted to their environment. Further research is required to elucidate AM function in and specific adaptations to YNP's thermal areas.
Bunn, Rebecca A. and Zabinski, Catherine A.
"Arbuscular mycorrhizae in thermal-influenced soils in Yellowstone National Park,"
Western North American Naturalist: Vol. 63
, Article 1.
Available at: http://scholarsarchive.byu.edu/wnan/vol63/iss4/1