Mycorrhizal associations of nursery grown Scots pine (Pinus sylvestris L.) seedlings in Poland

We investigated the species richness and composition of mycorrhizal fungi naturally colonizing one- and two-year-old Pinus sylvestris L. seedlings from four bare-root nurseries in Poland. We hypothesized that both edaphic factors and seedling age would affect ectomycorrhizal (ECM) community structure. We assessed the relative abundance of mycorrhizal morphotypes and distinguished ECM fungi present on root tips using RFLP ( restriction fragment length polymorphism) of the ITS ( internal transcribed spacer) of fungal rDNA. Most of the RFLP types were identified by comparing RFLP patterns with reference data obtained from regional sporocarps and isolates of ectendomycorrhizal species. Samples of unidentified RFLP types and representatives of suilloid RFLP patterns were sequenced and compared with available sequences. Overall, we identified 13 fungal species, with species richness varying from two to eight species among nurseries. The dominant species in each examined nursery were Wilcoxina mikolae and Thelephora terrestris. Suilloid fungi were also abundant in most of the nurseries. S. variegatus was the most frequent suilloid species among the nurseries. Seedling age affected the relative abundance of ECM species to some extent. Principal component analysis (PCA) revealed a lack of apparent correlations between the relative abundances of species and edaphic factors. Factors that may contribute to the maintenance of ECM community structure are discussed.