Study On Chemical Characterization In Tissue Cell Of Moso Bamboo (Phyllostachrs Pubescens) At Different Age

Moso bamboo(Phyllostachrs pubescens), which has wide planting area and great potential use in China, was selected as research raw materials. Chemical composition, extractives with organic solvents, phenolic acids content, cell-wall polysaccharides, distribution of lignin and crystallinity of cellulose were studied separately, in order to obtain more information about chemical characterization during growing process of moso bamboo. The main conclusions were summarized as follows.The chemical components in dichloromethane extractives were almost same in moso bamboo with four different ages.2,6-dimethoxybenzoquinone,4-((1E)-3-hydroxy-l-propenyl)-2-methoxyphenol and nonacosane were characterized in the 4 kinds of moso bamboo. Among the 4 kinds of bamboos, the contents of quinones, phenols, ester and alkanes were the highest in 7-year moso bamboo. It implies that the relative contents of the compounds increase with the bamboo age going up.The total phenolic acids contents in cell walls of moso bamboo at four different ages ranged from 0.3270μg-mL-1 to 1.6352μg-mL-1, and increased with bamboo growing. Four kinds of phenolic acids, which were gallic acid, ferulic acid, cinnanic acid and caffeic acid, existed in moso bamboo cell walls of all ages. The increases of gallic acid, ferulic acid and caffeic acid had the same trend with the lignin, to some extent, indicated tightly relationship with lignifications of moso bamboo cells.In study of cell-wall polysaccharides, the results shown that cell walls of moso bamboo consisted mainly of arabinose, galactose, glucose, xylose residues, while the contents of other four compositions were scarce, especially mannose residues. Galactose and arabinose had significantly influence on changes in side pectic chains of moso bamboo, and arabinose, glucose and xylose were contributed to the growth of moso bamboo woods.The distribution of lignin in cell walls of moso bamboo were determined using KMnO4 dyeing (Maule method) combined with TEM. With TEM, the color was observed heaviest in the cell corner (CC) and composite middle lamella (CML), lightest in secondary wall S3 layer and gradually reduced from S1 layer to S3 layer. By use of SEM-EDXA, the content of Mn element was highest in middle lamella of cell wall, and gradually decreased from second wall S1 layer to S3 layer. This indicated the middle lamella of cell wall contained largest lignin, and the content reduced from middle lamella to second walls.By means of X-ray diffraction (XRD), the powder of moso bamboo at different age was sampled and tested. The peak, crystal face of 002, was existed at 22.4°(2θ). The degree of relative crystallinity was calculated using Segal method. It indicated the relative crystallinity (CrI%) was much varied during the growth of moso bamboo. The CrI%, at top and bottom position, was decreased firstly and then increased with the moso bamboo aging. While it was increased firstly and then maintaining stability in middle position.