Mycorrhizal status of invading Pseudotsuga menziesii seedlings in Nothofagus spp. forests from Patagonia, Argentina

SALGADO SALOMÓN M.E.; RAJCHENBERG M.; BARROETAVEÑA C.

Belo Horizonte, Brasil

Congreso; 6th International Conference on Mycorrhizae; 2009

ICOM, Universidade Federal de Belo Horizonte

Pseudotsuga menziesii is one of the most widely planted conifers in the Patagonian Andes region of Argentina, and its invading characteristics have been widely reported. Invasion would be strongly conditioned by its autoecology, environmental variables and the establishment of shared mycorrhizal associations. In this study, the ecto- ectendo- and endomycorrhizae present in P. menziesii seedlings growing in Nothofagus-P. menziesii matrix were evaluated and analyzed in relation to environmental parameters. Three study sites were selected and characterized. One transect along the effective recruitment area was established at each site in order to wrench 25 seedlings along with a soil sample. Colonization percentage and richness of EM, ECM and VAM associations were evaluated and pH, total N, OM %, CEC (cationic exchange capacity), electrical conductivity and available P were determined from soils. The association between variables was analyzed using PCA. It was found that invading seedlings had >75% EM and ECM mycorrhization, and morphotype richness varied between sites, although Rhizopogon, Wilcoxina vel aff. and Hebeloma morphotypes were always dominant. VAM colonization varied between 25-40%, with different proportions of Arum and Paris types between sites, but with a constant presence of dark-septate endophytes. High mycorrhizal colonization was positively associated with soil OM, total N and electrical conductivity, and negatively with precipitation and Ca.