Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Diversidad funcional de los hongos micorrizógenos arbusculares de islas de recursos del Valle del Mezquital, Hidalgo

FUNCTIONAL DIVERSITY OF ARBUSCULAR MYCORRHIZAL FUNGI OF RESOURCE ISLANDS MEZQUITAL VALLEY, HIDALGO

Auteur : García Sánchez, Rosalva.

Université de soutenance : Colegio de Postgraduados (COLPOS) Consejo Nacional de Ciencia y Tecnología (CONACYT)

Grade : Doctorado en Ciencias, especialista en Botánica 2011

Résumé
This study was conducted at the Mezquital Valley, Hidalgo. This valley is characterized by secondary and fragmented vegetation in where the presence of resources islands is common. This research assessed the effect of Prosopis laevigata and Mimosa biuncifera, together and separate, on plant diversity (shrub species) and on soil properties. This study also provides information about the richness and diversity of arbuscular mycorrhizal fungi (AMF) associated to the under canopy soil of P. laevigata and M. biuncifera collected from three xeric shrublands with different predominance of those legumes. In addition an experiment was conducted under greenhouse conditions in which AMF from three different sites were evaluated on their effectiveness for promoting the growth of both legumes. As results, there were recorded 45 species of shrubs at the Mezquital Valley, in which the plant species with high importance values were Hechtia podantha, Jatropha dioica, Lantana camara, M. biuncifera, Opuntia stenopetala and P. laevigata ; the similarity between the three conditions was 30 to 40%. The soils were rich in nutrients under the canopy of legumes. In the site 3 (Rincón) coexisted P. laevigata and M. biuncifera that result in improved soil conditions and in creating microhabitats that are occupied by different species, thus promoting both plant and AMF diversity. Twenty-six morphospecies of AMF were identified and represented 13 genera. Seasonality did not influence the richness of AMF morphospecies, but affected the spore abundance. The site 3 showed 21 morphospecies and high AMF diversity, but the greatest spore abundance was found in non-vegetated soil from the site 2 (González). The species M. biuncifera acted as an important reservoir of AMF. Regardless the origin of AMF inocula, P. laevigata and M. biuncifera showed a positive responsiveness to mycorrhizal inoculation, but M. biuncifera showed the better responses and greater mycorrhizal dependency. The AMF inocula from site 2 and site 3 significantly improved promoted better growth responses in both legumes, and both sites corresponded to those in which a high AMF-richness or spore abundance were achieved. Nevertheless, the three sites had a very good potential of native AMF to colonize P. laevigata and M. biuncifera. This finding supports the hypothesis that AMF may be an important component to understand how the two legume species maintain their dominance in the shrublands at the Mezquital Valley

Mots clés : Mezquital Valley, Abuscular mycorrhizal fungi (AMF), Prosopis laevigata, Mimosa buncifera, plant diversity, semiarid-thorny shrublands, soil nutrients.

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