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

This study presents root colonization of <em>Deschampsia cespitosa</em> 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 <em>D. cespitosa</em> 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 (<em>F</em>%), intensity of root cortex colonization (<em>M</em>%), intensity of colonization within individual mycorrhizal roots (<em>m</em>%), and arbuscule abundance in the root system (<em>A</em>%) 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: <em>Archaeospora trappei</em>, <em>Funneliformis mosseae</em> and <em>Scutellospora dipurpurescens</em>. The fourth species <em>Glomus tenue</em> colonized roots of <em>D. cespitosa</em> and was observed in the root cortex at 20–40 and 40–60 soil depth, however, its spores were not found at the site.

Arbuscular mycorrhiza of endemic and endangered plants from the Tatra Mts

The mycorrhizal status of 24 plant species considered as endemic, endangered in Poland and included in the IUCN Red List of Threatened Plants is reported. Selected plants and rhizosphere soil samples were collected in the Tatra Mts (Western Carpathians). Individuals of seriously threatened taxa were obtained from seeds and inoculated with available AM fungal strains under laboratory conditions. AM colonisation was found in 16 plants; 9 species were of the Arum-type, 4 - Paris and 3 taxa revealed intermediate morphology. The mycelium of the fine endophyte (<em>Glomus tenue</em>) and dark septate fungi (DSE) were observed in the material collected in the field. 20 AMF species (<em>Glomeromycota</em>) found in the rhizosphere of the investigated plants were reported for the first time from the Tatra Mts. The results provide information that might be useful for conservation and restoration programmes of these species. Application of AMF in active plant protection projects is discussed.

Colonization by arbuscular mycorrhizal and fine endophytic fungi in herbaceous vegetation in the Canadian High Arctic

The occurrence of arbuscular mycorrhizal (AM) fungi was surveyed along a latitudinal gradient in Arctic Canada including Banks Island (73°N), Devon Island (74°N), Ellesmere Island (76°N), and the Magnetic North Pole at Ellef Ringnes Island (78°N). At Banks Island, AM fungi were present and colonized at a high intensity in all specimens of Potentilla hookeriana Lehm. – Potentilla pulchella R.Br., Arnica angustifolia Vahl, and Erigeron uniflorus L. ssp. eriocephalus (Vahl ex Hornen.) Cronq. sampled. The soil collected under these plants showed a high inoculum potential when tested at greenhouse conditions using Plantago lanceolata L. as a bait plant. Occasional occurrence of AM fungi was recorded in Festuca hyperborea Holmen ex Frederiksen, Trisetum spicatum (L.) Richt., and Potentilla hookeriana – Potentilla pulchella at Devon Island. Despite the fact that potential AM plants are present, no AM was found at the two most northern sites, Ellesmere Island and Ellef Ringnes Island. There seems to be climatic or dispersal limitations to AM colonization at these northern sites. Fine endophytic fungi, formerly named Glomus tenue (Grenall) I.R. Hall, were recorded at all four sites, but most frequently at Banks Island. We thereby provide further evidence that fine endophytes are more frequent in harsh climatic conditions than AM fungi. There was a relatively high proportion of nonmycorrhizal plant species at all sites, and this proportion increased towards the north.Key words: arctic, arbuscular mycorrhiza, fine endophytes, dark septate fungi.