ABSTRACT At the Brazilian Amazon forest, studies were carried out to estimate the community of arbuscular mycorrhizal fungi (AMF), from this it was used a bioassay of dilutions of samples collected from preserved and regenerated areas after bauxite extraction. To regenerate areas, tree species were introduced and samples were taken after 2, 6, 12, and 16 years, the spores obtained were compared to those obtained by direct extraction and the number of species recovered from the bioassay was significantly higher. Therefore, the species founded after different periods regeneration was similar to the ones from the native forest. Since the early years of revegetation, the number of rare species was high with strong dominance of G. macrocarpum. Among older communities this high dominance decreased while at the same time, there was an increase in the number of individuals from other AMF species, concluding that the number of species did not change with the age of the revegetation.

O processo de recuperação de áreas degradadas pode ser favorecido pela inoculação de plantas com fungos micorrízicos arbusculares (FMA), selecionados para efetividade e competitividade. Com o objetivo de avaliar o estabelecimento e a capacidade infectiva (CI) de fungos introduzidos em relação à comunidade de fungos autóctones (FA), foram conduzidos dois experimentos em casa-de-vegetação. No primeiro, foram cultivadas 10 espécies de plantas (três gramíneas e sete leguminosas) com três tratamentos de inoculação [controle; G. margarita (CNPAB 001); G. clarum (CNPAB 005)]. No segundo, a Cl dos FMA foi avaliada no solo após o primeiro experimento, em bioensaio com plantas-iscas repicadas semanalmente para vasos contendo solo autoclavado. O estabelecimento e a Cl dos FMA foi baseada na presença de esporos após os cultivos. Os FMA introduzidos e as espécies vegetais influenciaram de modo diferenciado a esporulação dos FMA (Acaulospora rugosa, Entrophospora colombiana, Gigaspora margarita e Glomus macrocarpum). A inoculação possibilitou o estabelecimento dos fungos inoculados em todas as plantas avaliadas. No entanto, somente G. clarum apresentou Cl frente a população de fungos autóctones. Foi constatado que a CI destes isolados não está relacionada com o número de esporos. A produção de inoculantes comerciais a partir destes fungos é discutida.

The processes of recovering degraded lands may be benefited by the inoculation of selected arbuscular mycorrhizal fungi (AMF), for effectivety and competitiveness. Two greenhouse experiments were carried out, with the aim of evaluating the establishment and infective capacity (IC) of introduced fungi in relation to community of autochthonous fungi (AF). In the first study, 10 plant species were cultivated (three grasses and seven legumes) with three inoculum treatments [control; G margarita (CNPAB 001); G clarum (CNPAB 005)]. In the second study, the IC of the AMF was evaluated in the soil after the first experiment in bioassays, with trap plants transplanted weekly to pots containing autoclaved soil. The establishment and IC of AMF were based on the presence of spores after harvest. The introduction of AMF and the plant species influenced the sporulation of AF (Acaitlospora rugosa, Entrophospora colombiana, Gigaspora margarita and Glomus macrocarpum) in a differentiated way. The inoculation made the establishment of the inoculated fungus in all tested plants possible. However, only G. clarum presented IC to compete with the autochthonous fungi. The IC of these isolates showed no relationship to number of spores. The production of commercial inoculum using these fungi is discussed.