Fungos micorrízicos arbusculares (Glomeromycota) em um contínuo de restinga e caatinga, na reserva de desenvolvimento sustentável Estadual Ponta do Tubarão-RN

Abstract

The coastal zone is characterized by a transition between biomes or phytophysiognomies and may present stressful environmental conditions. In Rio Grande do Norte State (Brazil), this transition occurs due to the overlap (ecotone) between restinga and caatinga, distinct phytophysiognomies, characterized by mosaic formations. In addition to the flora adaptations to this interface, another important factor for the survival of plant species is the arbuscular mycorrhizal fungi (AMF), which are important symbionts that are relevant for the stabilization of the soil-plant system. In view of its ecological importance, this work aimed to identify the diversity of the AMF community in a restinga and caatinga continuum along the Northeastern coast, in the Ponta do Tubarão Sustainable Development Reserve, in Macau / Guamaré Counties, RN, Brazil. Two soil collection were carried out, one at the end of the period after rainfall and another in the dry period for AMF species identification by spore morphology. The soil abiotic factors and their influence on the AMF community were assessed. Twenty - four species were identified, 12 of which are exclusive to restinga, one (1) to caatinga and 11 occurred in both areas. As for the seasonal dynamics, the dry period showed a greater abundance of spores, and in the rainy season sporocarpic species, with agglomerates forming bunches of spores, were frequently found. The environmental factors that most influenced the distribution of the species were salinity and pH. The salinity, as well as the other chemical aspects of the soil verified, was homogeneous, being found some specific sites more saline, which presented a low species richness. This result suggests a significant impact of one of the main economic activities of the RN, the salines, on the biodiversity of AMF in the soil.