Mycorrhizal colonisation patterns of Tilia trees in street, nursery and forest habitats in southern Finland

Ectomycorrhizal fungi were characterised by restriction fragment length polymorphism (RFLP) and sequencing from Tilia cordata Mill root tips collected from forest, street and nursery habitats. Fungal colonisation intensity of roots was 80–90% in forest and street habitats and 60–70% at the nursery. On the whole, more Basidiomycota than Ascomycota were encountered in Tilia mycorrhizas, and soil horizons at depth of 5–10 cm contained more root tips and had higher diversity of mycorrhizal fungi than soils at depth of 20–25 cm. Healthy street trees and forest trees had the highest number of ectomycorrhizal morphotypes. Street and nursery trees did not have any common mycorrhizal fungal genera, whereas Boletus, Inocybe and Russula spp. were found from roots of both street and forest trees and Tuber spp. from roots of nursery and forest trees. Most of the genera found in this study do not have an earlier record of including Tilia root symbiotic species in Finland, although several but not all have been reported from other countries.