Continuity of ectomycorrhizal fungi in self-regenerating boreal Pinus sylvestris forests studied by comparing mycobiont diversity on seedlings and mature trees. New Phytol

Swedish University of Agricultural Sciences, Uppsala, Uppsala, Sweden
New Phytologist (Impact Factor: 7.67). 03/1999; 142(1):151 - 162. DOI: 10.1046/j.1469-8137.1999.00383.x


Seedlings and old trees of Scots pine in self-regenerating, old, virgin boreal forest in northern Sweden were compared in terms of the species composition of their associated ectomycorrhizal (EM) fungi. The natural regeneration of seedlings was mimicked by annual seeding for 10 yr (1986–1995) in intact field vegetation at three sites. In 1995, all seedlings were harvested, and 171 were examined for mycorrhizas. Twenty-five soil cores were taken in order to study the mycorrhizas on the established trees. Most short roots were mycorrhizal. Using mycorrhizal morphology and restriction fragment length polymorphisms (RFLP) analysis, we were able to distinguish 43 ectomycorrhizal taxa. Fourteen of these taxa were identified using a sporocarp and mycelial culture based internal transcribed spacer (ITS)-RFLP reference database, and another three were identified by mycorrhizal morphology. Cenococcum geophilum, Piloderma croceum and Suillus variegatus were present on the seedlings, irrespective of age, as well as on the old trees. At one forest, 23 ectomycorrhizal taxa were found as mycorrhizas, of which 10 occurred on both seedlings and old trees. These 10 species accounted for 92 and 73% of the mycorrhizas on the seedlings and old trees, respectively. A 3-yr survey of ectomycorrhizal sporocarps at the same site revealed 62 EM taxa. The degree of similarity between the composition of EM species reflected by sporocarps and by mycorrhizas, was low. Ectomycorrhizal species present in our ITS-RFLP database constituted 7.5–19% of the mycorrhizas on seedlings and old trees, whereas they constituted 80–95% of the total production of epigeous sporocarps. The unidentified taxa comprised 70–87% of the mycorrhizas. Our findings support the view that the species composition of mycorrhizas colonizing naturally regenerated seedlings in forests is similar to that of mycorrhizas colonizing surrounding trees. We suggest that the concept of the mycelial network be expanded in order to embrace both the significance of interconnections between different trees as well as the continuity or perpetuation of EM fungal communities.

Download full-text


Available from: Anders Dahlberg, Sep 08, 2015
  • Source
    • "In many temperate and boreal forest ecosystems the dominant tree species present form ectomycorrhizal associations. The host–fungus symbiotic compatibility, the ease of inoculum production and the fungal ecological adaptability to the transplantation site are some important criteria to select ECM fungi for nursery mycorrhization programmes (9). Inoculation with selected ectomycorrhizal (ECM) fungi has often been identified as a promising nursery cultural practice to improve the quality of the seedling stock and its performance after out-planting (14). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Pinus densiflora seedlings were inoculated with three indigenous ectomycorrhizal fungi (Cenococcum geophilum, Rhizopogon roseolus and Russula densifolia) in single-, two-, and three-species treatments. After 8 months, the colonization rates of each ectomycorrhizal species, seedling growth and the nutrition were assessed in each treatment. P. densiflora seedlings inoculated with different ECM species composition showed an increase in height and basal diameter and improved seedling root and shoot nutrition concentrations compared to control treatment. Generally, combined inoculation had a more positive influence on the seedlings than the single inoculation. The three-species inoculation presented the highest growth and basal diameter and concentration of most nutrients except potassium. In conclusion, the results provided strong evidence for benefits of combined inoculation with the indigenous ectomycorrhizal fungi on P. densiflora seedlings under controlled conditions.
    Brazilian Journal of Microbiology 07/2011; 42(3):1197-204. DOI:10.1590/S1517-838220110003000045 · 0.59 Impact Factor
  • Source
    • "Many EM species such as P. involutus form densely packed rhizomorphs (Read, 1992), and these thickened structures have a decreased surface area:volume ratio which could make them more resistant to degradation (Langley and Hungate, 2003). In addition, despite the high levels of species richness in EM communities (Jonsson et al.,1999), they tend to be dominated by few species, with many 'rare' species present in low abundance (Erland and Taylor, 2002 "
    [Show abstract] [Hide abstract]
    ABSTRACT: The ectomycorrhizal mycelium is a large component of boreal and temperate forest soil microbial biomass and the resulting necromass is likely to be an important source of nutrients for saprotrophic microorganisms. Here we test the effects of species richness of ectomycorrhizal mycelial biomass on short-term CO2 efflux by amending forest soil with necromass from 8 fungal species added separately and in mixtures of 2, 4 and 8 species. All additions of necromass rapidly increased soil CO2 efflux compared to unamended controls but CO2 efflux increased significantly with species richness. Efflux of CO2 did not correlate with the carbon (C) or nitrogen (N) contents or the C:N ratio of the added necromass. The study demonstrates that species diversity of dead ectomycorrhizal fungal hyphae can have important consequences for soil CO2 efflux, and suggests decomposition of hyphae is regulated by specific constituents of the nutrient pools in the necromass rather than the total quantities added.
    Soil Biology and Biochemistry 06/2011; 43(6):1350-1355. DOI:10.1016/j.soilbio.2011.03.009 · 3.93 Impact Factor
  • Source
    • "The dominance of C. geophilum on the four tree species in this study may be affected by the high competitive abilities and wide ecological amplitude of this fungus (Pigott 1982; Jonsson et al. 1999; Izzo et al. 2005). Moreover, that C. geophilum reaches its highest relative abundance on Q. rubra (Table 2) rather than the other tree species studied may be of interest. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Non-native tree species have been widely planted or have become naturalized in most forested landscapes. It is not clear if native trees species collectively differ in ectomycorrhizal fungal (EMF) diversity and communities from that of non-native tree species. Alternatively, EMF species community similarity may be more determined by host plant phylogeny than by whether the plant is native or non-native. We examined these unknowns by comparing two genera, native and non-native Quercus robur and Quercus rubra and native and non-native Pinus sylvestris and Pinus nigra in a 35-year-old common garden in Poland. Using molecular and morphological approaches, we identified EMF species from ectomycorrhizal root tips and sporocarps collected in the monoculture tree plots. A total of 69 EMF species were found, with 38 species collected only as sporocarps, 18 only as ectomycorrhizas, and 13 both as ectomycorrhizas and sporocarps. The EMF species observed were all native and commonly associated with a Holarctic range in distribution. We found that native Q. robur had ca. 120% higher total EMF species richness than the non-native Q. rubra, while native P. sylvestris had ca. 25% lower total EMF species richness than non-native P. nigra. Thus, across genera, there was no evidence that native species have higher EMF species diversity than exotic species. In addition, we found a higher similarity in EMF communities between the two Pinus species than between the two Quercus species. These results support the naturalization of non-native trees by means of mutualistic associations with cosmopolitan and novel fungi.
    Mycorrhiza 05/2011; 22(2):121-34. DOI:10.1007/s00572-011-0387-x · 3.46 Impact Factor
Show more