Arbuscular mycorrhiza of Deschampsia cespitosa (Poaceae) at different soil depths in highly metal-contaminated site in southern Poland

This study presents root colonization of Deschampsia cespitosa growing in the immediate vicinity of a former Pb/Zn smelter by arbuscular mycorhizal fungi (AMF) and dark septated endophytes (DSE) at different soil depths. AMF spores and species distribution in soil profile were also assessed. Arbuscular mycorrhiza (AM) and DSE were found in D. cespitosa roots at all investigated soil levels. However, mycorrhizal colonization in topsoil was extremely low with sporadically occurring arbuscules. AM parameters: frequency of mycorrhization of root fragments (F%), intensity of root cortex colonization (M%), intensity of colonization within individual mycorrhizal roots (m%), and arbuscule abundance in the root system (A%) were markedly higher at 20–40, 40–60 cm soil levels and differed in a statistically significant manner from AM parameters from 0–10 and 10–20 cm layers. Mycorrhizal colonization was negatively correlated with bioavailable Cd, Pb and Zn concentrations. The number of AMF spores in topsoil was very low and increased with soil depth (20–40 and 40–60 cm). At the study area spores of three morphologically distinctive AMF species were found: Archaeospora trappei, Funneliformis mosseae and Scutellospora dipurpurescens. The fourth species Glomus tenue colonized roots of D. cespitosa and was observed in the root cortex at 20–40 and 40–60 soil depth, however, its spores were not found at the site.