Avaliação de fungos micorrízicos arbusculares e ectomicorrízicos para seleção de simbioses eficientes com leguminosas arbóreas do gênero Acacia. / Arbuscular mycorrhizal and ectomycorrhizal fungi evaluation for selection of efficient symbiosis for leguminous trees of Acacia genus.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The present research aimed the selection of FMA and isolate of fECTOs of high symbiotic efficiency for Acacia mangium, Acacia holosericea, and Acacia auriculiformis with the purpose of evaluating the best combination of inoculation among the different types of mycorrhizae. The experiments were carried on at Embrapa Agrobiologias greenhouse, in Seropédica/RJ. The soil used was classified as an Udult and it was sampled in Pinheiral municipality, RJ State. At first, three experiments were conducted for the selection of the most efficient FMAs, one for each species of Acacia. Three other experiments were conducted for the selection of isolate of fECTOs equally efficient for the same vegetal species. The experimental delineation used was of casualized blocks with 5 replicates for each treatment. The species of FMA treated were: Acaulospora laevis, Acaulospora morrowiae, Entrophospora colombiana, Entrophospora contigua, Gigaspora margarita, Glomus clarum, Scutellospora calospora, Scutellospora heterogama, Scutellospora gilmorei and Scutellospora pellucida. The isolate off ECTOS tested were: UFSC Pt116; UFSC Pt24; UFSC Pt193; O 64ITA6; UFSC Pt187 and O 40ORS 7870. Following the first results, the mycorrhizae most efficient for the vegetative growth were re-tested and the treatments for each arboreal species were: the best FMAs; best fECTOs; and the combination of these fungi and a non-inoculated reference. In all experiments the growth of plants was measured using fresh and dry weights of roots and aerial parts. The roots were evaluated by the FMAs and fECTOs colonization. The FMA spores were counted, after removed from the soil by sieving and centrifugation. The symbiotic efficiency was evaluated by comparing the responses to the reference treatment non inoculated in term of aerial dry matter. The FMAs which presented the highest values for the vegetative growth and mycorrhizae colonization for the Acacia species studied were: Acaulospora morrowiae, Scutellospora calospora and Scutellospora heterogama; proving to be the fungi with best symbiotic efficiency for these plants. In the inoculated experiments with isolates of fECTOs, none of the isolates proved to be efficient for the Acacia species tested. The O64 ITA 6 (Pisolithus tinctorius) isolate gave plants with higher mycorrhiza colonization and it was selected. In the experiments of combined inoculation, the treatments that resulted in highest vegetative growth were: A. morrowiae+S. calospora+O64ITA6; S. calospora+S. heterogama+O64ITA6; A. morrowiae+S. calospora+S. heterogama e A. morrowiae+S. calospora+S. heterogama+O64ITA6; proving to be the treatments with best symbiotic efficiency for the Acacia species tested. These combinations presented values of mycorrhiza colonization above 70%. In this sense, the mixture of FMAs and fECTOs may be considered an ideal practice for the Acacia genus, though needing a previous knowledge of the behavior of the combination, aiming the optimization of their association.

ASSUNTO(S)

co-inoculação co-inoculation mycorrhiza colonization. colonização micorrízica symbiotic efficiency eficiência simbiótica degraded lands agronomia áreas degradadas inoculante.

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