Fungos micorrízicos arbusculares no bioma Caatinga: ecologia e caracterização da estrutura da comunidade de FMA em função da variação na fisionomia vegetal

Abstract

The Caatinga is a biome with high diversity of arbuscular mycorrhizal fungi (AMF). The variation of vegetation types within the biome, as well as seasonal effects and the chemical properties of the soil can influence the community of AMF. Aiming to associate taxonomic diversity and activity of mycorrhizal fungi to changes in vegetation cover and the chemical and physical characteristics of the soil this study was proposed. The analysis of the relationship of the production of glomalin, a protein produced only by organisms of Glomeromycota phylum, chemical and physical characteristics of soil (carbon content and watter stability aggregate); determining environmental aspects related to diversity and richness of AMF species in areas of Caatinga; to investigate the seasonal dynamics of the community of AMF and its activity and influence on the occurrence of AMF in the Araripe were also initially proposed objectives and are answered in the three chapters of the thesis. The study area is very important both to be situated in a typically brazilian biome and to be inserted into a plateau, allowing peculiarities variations in vegetation. Soil samples were collected seasonally during the period of 2011 to 2013 at the beginning and at the ending of the rainy and dry seasons. We identified the species of AMF that occured on ‘brejo de altitude’ (BA), ‘carrasco’ (CA) and ‘cerradão’ (CE) and also the seasonal variation on communities of AMF. Seasonality is an important factor to the populational dinamic of arbuscular mycorrhizal fungi. The biology, the production of glomerospores and glomalin, and the community composition were affected by the water regim. Each fisionomy has peculliarities in soil chemical proprieties and AMF community composition. The diversity of AMF was high in the Araripe plateau with 87 species identified. The genus Acaulospora and Glomus were predominant on ‘brejo de altitude’ and spores gigasporoids were dominant on ‘carrasco’ and ‘cerradão’.