Mónica A. Lugo

Native arbuscular mycorrhizal fungi (AMF) from mountain grassland (Córdoba, Argentina) I. Seasonal variation of fungal spore diversity

Arbuscular mycorrhizal fungi (AMF) were studied in the rhizosphere of 3 Poaceae with metabolic pathway C3 (Briza subaristata Lam., Deyeuxia hieronymi (Hack.) Türpe and Poa stuckertii (Hack.) Parodi), 2 Poaceae with C4 metabolic type (Eragrostis lugens Nees and Sorghastrum pellitum (Hack.) Parodi.), and a Rosaceae (Alchemilla pinnata Ruíz & Pav.) from a natural mountain grassland in Central Argentina (South America). Host species, their metabolic type, seasonal changes, and grazing effects over AM fungal diversity were analyzed. Seventeen mycorrhizal fungi taxa were found, widespread in all families of Glomales. Density of endomycorrhizal fungi was found to be strongly influenced with seasons and host metabolic pathway, although biodiversity (H), richness (S) and evenness (E) did not change. In most cases grazing did not affect these variables.

Taxonomic and Functional Response of Arbuscular Mycorrhizal Fungi to Land Use Change in Central Argentina

It has been predicted that land use change will pose the main threat to biodiversity worldwide (Sala et al. 2000). A recent meta-analysis shows that, at local scale, conversion and degradation of habitats promote on average a global decline of 8.1 % of species richness and 10.1 % of abundance (Newbold et al. 2015). These human-mediated changes in biodiversity strongly affect ecosystem stability (Hautier et al. 2015). Given the importance of biodiversity on ecosystem functions and services, studies on the effects of land use on species assemblages are highly relevant in current global context.

Arbuscular mycorrhizas and dark septate endophytes associated with grasses from the Argentine Puna

ABSTRACT The Andean Puna is an arid, high-elevation plateau in which plants such as grasses experience high abiotic stress and distinctive environmental conditions. We assessed colonization by arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) in the roots of 20 native grass species and examined the relationship between root-associated fungi (AMF and DSE) as a function of the elevation of study sites, the photosynthetic pathways of the grass hosts, and the hosts’ life cycles. In general, grasses were co-colonized by AMF and DSE and the colonization by AMF and DSE was not extensive. The extension of colonization of AMF and that of DSE were positively correlated, as were number of arbuscules and DSE colonization extension. The extension of AMF colonization differed among sites with different elevations, but DSE colonization was similar across sites. Overall, AMF and DSE patterns shifted as a function of elevation in most grass species, with no general trends observed with respect to host photosynthetic pathway or life cycle. In general, our observations differ from previous studies in the Northern Hemisphere. Variation among sites in AMF and DSE colonization was greater than variation that could be explained by the other factors considered here, suggesting a strong influence of environmental factors. We predict that both AMF and DSE may have established synergistic and beneficial associations with grasses in these distinctive and harsh ecosystems.

Broomeia congregata Berk., 1844 (Agaricales: Broomeiaceae): New distribution record for San Luis, Argentina

Broomeia congregata Berk. is a gasteroid fungus with a predominant African distribution. However, it has been documented twice, in 1912 and 1973, as occurring in Catamarca Province (Argentina, South America). Nearly forty years later, a new finding is reported for San Luis Province, Argentina. The report includes new morphological information based on scanning electron microscopy (SEM). In addition, some phenological, biogeographical and ecological implications concerning B. congregata are discussed.