意杨三个无性系木材化学成份的变异

VARTABILITY IN THE CHEMICAL COMPOSITION OF THREE ITALIAN POPLAR CLONES

研究了意杨纸浆材三个无性系木材主要化学成份的变异规律。纤维素含量由髓心处47.57％增加到树皮附近51.74％;木素、多缩戊糖含量由髓心向外呈递减的趋势,二者分别由髓心处25.27％、24.42％减小到树皮附近23.78％、19.72％;纤维素、木素、多缩戊糖含量与生长轮年龄相关显著,呈二次抛物线关系。苯醇抽出物含量径向变化不太明显,平均值为1.17％,变动在0.16％～3.52％之间。树干轴向胸高位置向上木素含量先递减而后增加;纤维素含量在靠近髓心部分由下向上稍微递增,而树皮附近则先减小而后稍增;多缩戊糖含量在靠近髓心部位由下向上先稍增而后减小,树皮附近则呈减小的趋势;苯醇抽出物含量轴向变化与纤维素变化相似。意杨纸浆材三个无性系(I-63、69、72)间木材化学成份含量差异显著;无性系内株间化学成份仅72杨差异显著。从意杨不同伐龄全树化学成份含量来看,结合其生长特性,认为意杨纸浆材主伐林龄8～9年较好。

The variation in the chemical content value of three Italian poplars clones were reported in this paper. Cellulose content of wood in the radial direction increases from pith (47.57％) to bark (51.74％). Lignin (25.27％) and pentosan contents (24.42％) near the pith are higher than those (23.78％ and 19.72％) near the bark, their contents in the radial direction decrease outword. The content values (Y) of cellulose, lignin and pemtosan are singnificantly related to the ages (X) of growth ring, the regression model is a quadratic equation (Y=a+bx+cx^2). Variation patterns in benzen-alcohol extractive content value in the direction is not obvious. The extractive content values vary from 0.16％ to 3.52％, its mean is 1.17％. Along the trunk, lignin content from base to top first decreases, then increases. Cellulose content near the pith along the trunk, slightly increases from base to top; and that near the bark first decreases, then slinghtly increases. From base to top, pentosan content near the pith first increases, then decreases; and that near the bark decreases. Variation pattern in benzen-alcohol extractives contentalone trunk is similar to that in cellulose.Statistical analysis indicated that singnificant differences in chemical composition existed among three clones of Italian populus (I-63, I-69 and I-72). Within other clone singnificant difference in chemical composition was not found except I-72 clone. Based on variation in the whole tree's chemical composition and growth properties, harvesting of Italian populus for pulpwood at 8～9 age is good.