Arbuscular mycorrhizae of dominant plant species in the Yungas forests, Argentina.

BECERRA, A., M. CABELLO, M.R. ZAK & N. BARTOLONI.

MYCOLOGIA.

Allen Press

Año: 2009 vol. 101 p. 612 - 621

0027-5514

In Argentina, the Yungas forests are among the ecosystems most affected by human activity, with loss of biodiversity. To assess the arbuscular mycorrhizal (AM) colonization and the arbuscular mycorrhizal fungi (AMF) spore numbers in these ecosystems, the roots of the most dominant native plants (one tree: Alnus acuminata, three herbaceous: Duchesnea indica, Oxalis conorrhiza, Trifolium aff. repens, and one shrub: Sambucus peruviana) were studied throughout the year from two sites of the Yungas forests. Assessments of mycorrhizal colonization (% of root length, intraradical structures) were made by washing and staining the roots. Soil samples of each plant species were pooled and sub-samples were obtained to determine AM spore numbers. The herbaceous species formed both Arum- and Paris-type morphologies, whereas the tree and the shrub species formed single structural types of Arum- and Paris-type respectively. AM colonization, intra-radical fungi structures and AMF spore numbers displayed variation in the different species, seasons and sites. D. indica showed the highest AM colonization, whereas the highest spore numbers was observed in the rhizosphere of A. acuminata. There was no correlation between spore numbers and root length percentage colonized by AM fungi. Results of this study showed that Alnus acuminata is facultatively AM. The AM colonization, intra-radical fungi structures and AMF spore numbers varied in the different species depending on phenological, climatic and edaphic conditions.