<正>对不同生长期的毛竹进行定期采样，应用偏振光显微镜及图像处理技术研究毛竹横截面维管束结晶区的变化规律。结果表明：毛竹生长初期，厚壁细胞结晶比例的变化呈现线性增加；进入中龄期，毛竹开始木质化，纤维素比例降低，竹材厚壁细胞壁结晶比倒减少；到了后期毛竹木质化降低，毛竹结晶比例变化趋于缓慢并基本保持不变。

The liquefaction of Salix psammophila, Caragana intermedia and Populus × Eu ramericana(Doda)Guineir cv. ’I- 214) in the presence of phenol under sulfuric catalysis was studied. The effects of reaction temperature, liquid ratio (phenol/wood ratio), reaction time and catalyst content on liquefaction were investigated. The results show: (1) Under the optimum conditions Salix. Caragana and Populus liquefaction can get reasonable results, and the liquefaction Populus is much easier than Sali.r and Caragana. (2) The reaction temperature has a greatest influence on liquefaction process, moreover, liquefaction process is affected by liquefaction ratio, reaction time and catalyst content at a certain extent. (3)The optimum condition of liquefaction for Populus is estimated as: temperature of 150℃ the reaction time of 120 rain, liquid ratio (phenol/wood ratio) of 3 and catalyst content of 7%. Under the processing parameters of temperature of 150 ℃ the reaction time of 120 rain, liquid ratio (phenol/wood ratio) of 4 and catalyst content of 7%, the residues rate of Salix and,Caragana were satisfied.