Micromorphology of Bamboo Fibers Degraded by Brown-Rot Fungus Gloeophyllum trabeum
Kwang Ho Lee, Chang Hyun Cho, Yoon Soo Kim
The decay pattern of bamboo by brown-rot fungus was examined. In addition, the influence of polylaminate structures in bamboo fibers on the restriction of fungal decay was also investigated. The weight loss of bamboo Phyllostachys puberscens by the brown-rot fungus Gloeophyllum trabeum after 16 week incubation was about 25%. Parenchyma cells were severely degraded. Microscopical studies showed that G. trabeum removed the inner part of multi layers while the last layer in the polylaminate secondary walls, corresponding to S3 layer in the tracheids, remained essentially intact. Bamboo fiber walls were degraded at a considerable distance from fungal hyphae. Main decomposition of bamboo fiber cell wall by G. trabeum was similar to other brown-rot fungi in terms of preferential removal of inner part of secondary walls, remaining the last layer in polylaminate layer intact. Cytochemical work showed the production of hydrogen peroxide by the brown-rot fungus G. trabeum and the diffusion into the bamboo fiber walls. The effect of polylaminate structures and lignin levels at the narrow layers on restriction on fungal decay to bamboo fibers was also discussed.