Abstract:

Deterioration of culms of Phyllostachys pubescens after the treatment of ultraviolet irradiation was investigated by means of a scanning electron microscope (SEM), light microscope and colorimeter. SEM observation on the cross sections of the bamboo showed that the deterioration in the fibers started in inter-layers of secondary walls followed by the cell corners and the middle lamellae. While the deterioration in the parenchyma cells began from the cell corners followed by the middle lamellae. Consequently, all the cell walls were eroded. In terms of the colour reaction after 40 days of UV irradiation on the cross sections of bamboo surface, it was further determined that the deterioration reached a depth of 590 μm in the parenchyma and 146 μm in fiber from the surface. In addition, this study noticed that there exited sharp difference in colour and brightness after the treatment with the UV irradiation along the different directions. Finally, the mechanism of causing the structural changes was discussed as well.

Key words: Phyllostachys pubescens, Cell wall, Ultrastructure, Colour change, Ultraviolet irradiation