【作者】 解林坤；

【导师】 刘元； 吴义强；

【作者基本信息】 中南林学院 ， 木材科学与技术， 2005， 硕士

【摘要】 通过对广西东门林场五个粗皮桉(Eucalyptus pellita)家系(P4、P5、P9、P17、P18)的解剖特征、物理力学性质和化学性质的系统测试,以此为基础,进而用数理统计方法对所测粗皮桉家系在1.3m处的解剖指标(纤维长度、纤维宽度、纤维长宽比、二倍纤维径壁厚度、壁腔比、腔径比、微纤丝角)和化学性质(纤维素含量、戊聚糖含量、酸不溶木素含量、1%NaOH抽出物含量、热水抽出物含量、冷水抽出物含量、灰分含量、pH值)以及树高方向的物理力学性质(基本密度、干缩特性、抗弯弹性模量、抗弯强度、顺纹抗压强度、横纹抗压强度)进行讨论和分析,以期找出粗皮桉家系木材材性的变异规律及其材性之间的相互关系。结果表明:(1)粗皮桉家系的解剖指标、物理力学指标除差异干缩在a=0.01水平上差异不显著外,其余指标均在a=0.01水平上具有极显著差异;家系间酸不溶木素含量在a=0.01水平上达到极显著差异;1%NaOH抽提物含量在a=0.05水平上差异比较显著;纤维素含量在a=0.1水平上差异显著;多戊糖含量、热水抽出物含量、冷水抽出物含量、灰分含量和pH值在a=0.1水平上差异不显著。(2)纤维长度由髓心向外逐渐增大,到一定树龄后又开始减小,呈PanshinⅢ型;纤维宽度的径向变异与纤维长度相似,由髓心向外纤维宽度基本具有由内向外增大的规律;纤维长宽比在径向上的变异规律由髓心向外逐渐增大,到一定树龄后又开始减小或是趋于平稳:二倍纤维径壁厚度、纤维壁腔比在径向上的变异规律是由髓心向外呈逐渐增大的趋势;纤维腔径比、微纤丝角从髓心向外总的趋势是呈逐渐减小的规律。(3)弦向全干缩率沿树干高度向上的变异没有统一的规律;而基本密度、径向全干缩率和体积全干缩率沿树干高度上的变异是沿树干向上逐渐增大,到达一定高度后又开始减小;差异干缩沿树干高度向上有逐渐减小的趋势。(4)抗弯弹性模量、抗弯强度、顺纹抗压强度、横纹局部弦向抗压强度沿树高方向的变异规律是沿树高方向增大,到一定高度后又开始减小;横纹局部径向抗压强度和横纹全部径向抗压强度沿树干向上呈逐渐减小的趋势;横纹全部弦向抗压强度在家系间的变异没有统一的规律。(5)纤维素含量由心部到边部呈逐渐增大的趋势;多戊糖含量在径向上的变异没有统一的规更多还原

【Abstract】 The anatomical properties, chemical properties, physical and mechanical properties of E.pellita from five families(P4 P5 P9 P17 and P18) in Guangxi-Dongmen Forest Farm have been determined systematically through experiments. Furthermore the obtained data of one point three meters E.pellita families about anatomical index(including fiber length, fiber width, ratio of length to width, double radial wall thickness, ratio of double wall thickness to lumen diameter, ratio of lumen to cell diameter and microfibrilla angle),chemical properties(including the contents of cellulose, pentosan, lignin, 1%NaOH extractive, hot-water extractive, cold-water extractive, ash and PH value of wood) of E.pellita families on the height of one point three meters and physical and mechanical properties(including basic density, shrinkage properties, modulus of elasticity, bending strength, compression strength parallel to grain and compression strength perpendicular to the grain) with height in the tree were analyzed and discussed in details by means of mathematical statistics in order to seek the variance regularity and correlation of wood quality characters. The results indicated that: (l)The index of anatomical and the physical and mechanical of E.pellita families had extremely significant differences at 0.01 level except the variance shrinkage index. Among the six families of E.pellita, lignin contents had obvious difference at 0.01 level, 1%NaOH extractive and the contents of cellulose reached 0.05 and 0.1 level respectively. Whereas there were slight differences in the contents of pentosan, hot-water extractive, cold-water extractive, ash and PH value of wood at 0.1 level.(2)The fiber length increased gradually from pith outward, then decreased gradually at certain age showing a Panshin III variation pattern. Meanwhile the fiber width had the similar regulation to the fiber length. The ratio of length to width decreased gradually from pith outward, reached maximum at certain age, then decreased slightly or level off. From pith outward the double radial wall thickness and the ratio of double wall thickness to lumen diameter increased gradually, while the ratio of lumento cell diameter and the microfibrilla angle decreased gradually. (3) From the base upward, the tangential shrinkage of oven dried wood had no unitary regulation, whereas basic density, radial shrinkage of oven dried wood and volumetric shrinkage of oven dried wood increased gradually, then decreased gradually at certain height. Variance shrinkage decreased gradually.(4)The modulus of elasticity, bending strength, compressive strength parallel to grain and partial tangential proportional-limit of compressive strength perpendicular to the grain increased gradually from base upward, reached maximum at certain height, then decreased gradually. There existed a decreasing trend in partial and total radial proportional-limit of compressive strength perpendicular to the grain from base upward, while total tangential proportional-limit of compressive strength perpendicular to the grain had no unitary regulation.(5)From pith outward cellulose contents increased gradually, whereas the radial variance of pentosan contents had no unitary regulation. Between the families of E.pellita, there were slight differences in the contents of lignin among heart, center and edge. There existed a decreasing trend in 1%NaOH extractive form heart to edge. The center contents of hot-water extractives and cold-water extractives were all bigger than heart and edge. And the contents of ash and PH value of wood increased gradually from heart to edge. (6)Taking microfibrilla angle as independent, fiber length and width as dependent respectively made linear regression analysis. Among E.pellita families a notable negative linear regression was found between microfibrilla angle and fiber shape traits. (7) The linear regression were analyzed by taking basic density as independent, bending strength, compressive strength parallel to grain and volumetric shrinkage of oven dried wood as independent respectively. Between E.pellita families bending strength were positively correlated with basic density, the regression coefficient was above 0.619 and the effect of regression was notable except P18 family whose regression coefficient only reached 0.366.There also exited positively correlation between compressive strength parallel to grain and basic density and the regression coefficient reached above 0.8, while P5 family had weak correlation and the regression coefficient was only 0.245.更多还原