Mycorrhizal status of invading Pseudotsuga menziesii seedling in Nothofagus spp. forest from Patagonia

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

Belo Horizonte

Congreso; 6 International Congress of Mycorrhiza; 2009

International Mycorrhiza society

Pseudotsuga menziesii is one of the most widely planted conifers in the Patagonian Andes region of Argentina, although its invading characteristics have been widely reported. Invasion would be strongly conditioned by environmental variables and the establishment of shared mycorrhizal associations. In this preliminary study, the ecto- ectendo and endomycorrhizas present in P. menziesii seedlings growing in Nothofagus-P. menziesii matrix was evaluated and analyzed in relation to environmental parameters. Three study sites were selected and characterized. One transect along the effective invasion area was established in each one to wrench 25 seedling along with a soil sample. Colonization percentage and richness of EM, ECM and VAM associations was evaluated and pH, total N, OM %, CEC, 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, Aff. Wilcoxina 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.