Identificação e quantificação de fungos micorrízicos arbusculares autóctones em municípios produtores de citros no Rio Grande do Sul

Abstract

Resumo O objetivo deste trabalho foi identificar e quantificar os esporos de FMA presentes em viveiros e pomares de citros no Rio Grande do Sul. Foram coletadas amostras de solo e de raízes de dez viveiros e doze pomares de oito municípios produtores de citros, nas quais avaliaram-se conteúdo nutricional, número de esporos por 100 g de solo seco e colonização das radicelas, e determinaram-se as espécies autóctones. As espécies, em ordem decrescente de ocorrência, foram: Glomus macrocarpum > Scutellospora heterogama > Acaulospora scrobiculata = Acaulospora birreticulata > Glomus invermaium = Glomus occultum = Entrophospora colombiana > Glomus claroideum = Glomus constrictum > Scutellospora persica.Termos para indexação: Glomus, Scutellospora, Acaulospora, Entrophospora, colonização. Identification and quantification of native arbuscular mycorrhizae fungi of citrus in the State of Rio Grande do Sul, BrazilAbstract The objective of this work was to identify and quantify AMF spores present in citrus nurseries and orchards in Rio Grande do Sul, Brazil. Soil and root samples were collected at ten nurseries and twelve citrus orchards. Mineral composition of the soil samples was determined as well as the number of spores in 100 g of dry soil, root colonization and native species taxonomic identification. AMF species, in decreasing order of occurrence were: Glomus macrocarpum > Scutellospora heterogama > Acaulospora scrobiculata = Acaulospora birreticulata > Glomus invermaium = Glomus occultum = Entrophospora colombiana > Glomus claroideum = Glomus constrictum > Scutellospora persica.

Microbial Activity and Arbuscular Mycorrhizal Fungal Diversity in Conventional and Organic Citrus Orchards

“…The predominance of species of the genus Glomus was observed, in agreement with most of other studies performed on citrus (Nemec et al, 1981;Oliveira et al, 1986;Singh et al, 1992;Souza et al, 2002;Focchi et al, 2004). The exceptions were Siqueira et at.…”

“…In Brazil, orchards grafted onto 'Rangpur' lime in the states of Bahia and Sergipe and onto Poncirus trifoliata in Rio Grande do Sul showed mycorrhizal colonization between 60 and 80% (Weber & Oliveira, 1994;Souza et al, 2002). In other countries, samplings in citrus with several different rootstocks have also shown high root colonization levels: 85% in roots sampled in Basilicata, Italy (Schubert et al, 1993) and up to 90% in Florida, in the United States (Graham & Eissenstat, 1998).…”

Fungos micorrízicos arbusculares em cultivos de citros sob manejo convencional e orgânico

“…nodosa e Scutellospora pellucida foram consideradas raras, razão do baixo nú-mero de esporos identificados. Souza et al (2002), na região citrícola do Rio Grande do Sul, constataram também a predominância de espécies de Glomus, seguido de Acaulospora, Scutellospora e Entrophospora. Entretanto, esses autores identificaram dez espécies de FMA, e as mais freqüentes foram G. macrocarpum, em 95% das amostras, S. heterogama (86%), A. bireticulata e A. scrobiculata (41%) e E. colombiana (27%).…”

Arbuscular mycorrhizal fungi in papaya plantations of Espírito Santo and Bahia, Brazil

“…This is probably due to the use of subsoil, fumigated (25). But when nursery plants are grown directly in the soil, like some citrus systems, root may appear highly colonized (26). It was showed that nursery substrates mixed with more than 10% of cow manure reduce AM colonization in papaya seedlings (28).…”