Capacidade de deterioração de cepas de Eucalyptus spp. por fungos xilófagos
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Data
2011-12-15
Autores
Silva, Luciana Ferreira da
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Universidade Federal do Espírito Santo
Resumo
On the reform of the forest stand, after the cutting of trees, the remaining strains of Eucalyptus spp. must be removed. The natural degradation of stumps of eucalypts after clear cutting is slow. The mechanical destock raises the cost of production, involves machinery traffic on the ground favoring soil compaction and hindering the growth and distribution of roots. An alternative to the withdrawal of the remaining stumps is the employment of decomposing fungi. This research aimed to collect, isolate, select and identify fungi with potential for decayed eucalypts wood, from fragments of stumps to be used in an essay of accelerated decay and perform chemical analysis of sound wood and deteriorated by fungi isolated from stumps, which have greater ability to deterioration, to verify which components of wood suffered major changes as a function of decay by fungi. Samples of stumps of eucalypts, decomposed, were collected from commercial plantations, in three municipalities, with different altitudes and microclimates and wrapped in porous paper bags and transported to the Laboratório de Ciência da Madeira (LCM), in the Departamento de Engenharia Florestal (DEF), belonging to the Centro de Ciências Agrárias (CCA) of Universidade Federal do Espírito Santo (UFES) in the municipality of Jerônimo Monteiro, ES, Brazil. In LCM wood samples were taken to perform the isolation of fungi and subsequently obtaining pure cultures in culture medium Potato-Dextrose-Agar (PDA). A total of nine pure cultures were isolated and identified, being, three belonging to the Class Basidiomycetes fungi (Basidiomycetes 1, 2 and 3), four of the genus Trichoderma, one Lasiodiplodia and one Penicillium. The cultures were selected, subcultured in Petri dish and test tubes containing PDA and stored in air-conditioned room at 25 ± 2° C and used in the trial of accelerated decay. After 12 weeks of test, conclude that fungi isolated more efficient in the deterioration of wood were those belonging to the Class Basidiomycetes (1 and 2). Chemical analysis of wood decayed by Basidiomycetes 1 and 2, showed that there was an increase in total extractives content in wood, for both the Basidiomycetes tested. For the holocelulose (cellulose more hemicelluloses), there were minor differences between the healthy woods and decayed (variations averaging around 1%). The Basidiomycete 2 caused increased degradation of lignin when compared to Basidiomycete 1.
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Decayed stumps , Pure cultures , Xylophagous fungi , Natural Resistance , Cepas apodrecidas , Culturas puras , Fungos xilófagos , Resistência natural , Eucalipto
Citação
SILVA, Luciana Ferreira da. Capacidade de deterioração de cepas de Eucalyptus spp. por fungos xilófagos. 2011. Dissertação (Mestrado em Ciências Florestais) — Universidade Federal do Espírito Santo, Centro de Ciências Agrárias, 2011.