Comparação entre as técnicas de amostragem direta em campo e cultura-armadilha para mensuração da diversidade de espécies de fungos micorrízicos arbusculares

Abstract

-(Comparation between field sampling and trap culture techniques for measuring the diversity of arbuscular mycorrhizal fungi). Knowledge of arbuscular mycorrhizal fungi (AMF) communities depends of spores, which may not be available at the moment of collection. The main objective of this paper is the determination of AMF species diversity from direct collection carried out in the field and multiplication in pots. Five soil samples from three areas under no tillage were collected in order to isolate the spores and multiply the AMF in pots. Alfa and beta diversity indexes were used. The spores were extracted from the soil by wet-sieving and centrifugation in sucrose, mounted on semi-permanent slides and identified. In areas I, II and III, 12, 17 and 15 AMF species, respectively, were verified. In the multiplication pots, six species were isolated in area I, 12 in area II and 10 in area III. It was concluded that the survey of AMF diversity is more efficient when the both techniques are associated. Key words: Glomeromycota, no-tillage, taxonomy RESUMO -(Comparação entre as técnicas de amostragem direta em campo e cultura-armadilha para mensuração da diversidade de fungos micorrízicos arbusculares). O conhecimento das comunidades de fungos micorrízicos arbusculares (FMA) depende dos esporos, que podem ou não ser recolhidos na coleta. Este trabalho teve como objetivo determinar a diversidade de espécies de FMA a partir do exame de amostras do campo e de culturas-armadilha. Foram coletadas cinco amostras de solo em três áreas, a fim de isolar os esporos e realizar a multiplicação dos FMA em vasos. Os esporos foram extraídos do solo via peneiramento úmido e centrifugação em sacarose, montados em lâminas e identificados. As comunidades de FMA foram avaliadas por meio de índices descritores de alfa e beta diversidade. Nas áreas I, II e III verificaram-se respectivamente 12, 17 e 15 espécies. Nos vasos foram isoladas seis espécies na área I, 12 na área II e 10 na área III. Constatou-se que o levantamento da diversidade de FMA é mais eficiente quando as duas técnicas são associadas. Palavras-chave: Glomeromycota, plantio direto, taxonomia

The mosaic of habitats in the high-altitude Brazilian rupestrian fields is a hotspot for arbuscular mycorrhizal fungi

“…Due to the lack of information about the diversity of AMF in this ecosystem, we opted for samples that would cover the five habitats instead of performing a more detailed evaluation for only one of them. In fact, usually not all components of the mycorrhizal community are in the form of spores in a given sampling time (Bartz et al, 2008). This study assessed the occurrence of AMF in a single seasonal period; therefore, not all of the species present in the ecosystem had sporulated at the time of sampling (dry season).…”

Arbuscular mycorrhizal communities in different tropical pastures of the brazilian northeast

“…The species belonging to the family are able to colonize roots (BRUNDRETT et al, 1996;KLIRONOMOS;HART, 2002). According to BARTZ et al, (2008), the values may be underestimated even with the use of trap cultures for estimating MPN (Most Probable Number). These authors emphasize that many species remain in the vegetative form for a long time, suggesting the MPN technique for longer periods.…”