INVESTIGADORES
SOLANS mariana
congresos y reuniones científicas
Título:
INFLUENCE OF PINUS PONDEROSA PLANTATIONS ON SAPROPHYTIC AND SYMBIOTIC SOIL ACTINOMYCETES IN NORTHWEST PATAGONIA
Autor/es:
ARANCIBIA N.B., SOLANS M., CHAIA E.E.
Lugar:
Rosario
Reunión:
Congreso; IX Congreso de Microbiología General; 2013
Institución organizadora:
SAMIGE
Resumen:
For over 50 years, large areas of steppes and scrubs in northwestern Patagonia have been replaced by plantations of exotic conifers, which in several cases have an invader effect, as it happens with Pinus ponderosa. These plant invasions modify some physical and chemical environmental factors and alter biodiversity, while their effect on the soil actinomycetes is still unknown in the region. These microorganisms are a main component in the soil microbiota and play significant roles in nutrient cycling. The aim of this study was to analize the influence of P. ponderosa plantations on the abundance and diversity of saprophytic actinomycetes, and on the abundance of the symbiotic actinomycete Frankia, which induce nitrogen fixing nodules formation in the roots of some native species belonging to the Rhamnaceae family, such as Ochetophila trinervis (sin. Discaria trinervis). Soil samples were collected in six zones which included a P. ponderosa plantation, and each respective neighbour steppe or scrub site that was considered as a control. In order to characterize saprophytic actinomycetes isolation trials were performed with the soil samples applying chemotactic and sucessive soils dilutions methods. Abundance of infective Frankia was determined by evaluating its nodulation capacity, through a plant bioassay using O. trinervis as a trap plant. A physicochemical characterization of soils was conducted, as well as a description of plant diversity in each sampling site. It appeared that soils under P. ponderosa plantations did not affect the abundance and diversity of saprophytic actinomycetes, as compared with the neighbour steppe and scrubs. However, the nodulation capacity of Frankia strains infective on O. trinervis was lower in the pine plantations. Abundance of infective Frankia was positively correlated with soils pH, while it was negatively correlated with the age of the P. ponderosa plantations. According to these results we suggest that when pine plantations are planned in the region, it should be considered not only their effects on plant diversity but also their influence on soil microbial communities.