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1、Chapter 1 The Composition and Structure of Wood1Tianjin University of Science C 弦切面:垂直横切面与年轮相切的切面,又称切线切面 。Chapter 1 The Composition and Structure of Wood5Tianjin University of Science Chapter 1 The Composition and Structure of Wood39Tianjin University of Science 宽:20m。由于其长度短,直径 小,因此阔叶木浆不适于单独抄造高强度纸张。
2、 阔叶材中的纤维细胞含量低:6080。因此其制浆 造纸价值不如针叶材。 Chapter 1 The Composition and Structure of Wood91Tianjin University of Science & Technology2管 胞阔叶材中的管胞数量很少,但形态与针叶材的管胞相似,其细胞壁上的纹孔具缘纹孔,纹孔缘明显。管胞纹孔直径导管细胞的纹孔直径。Chapter 1 The Composition and Structure of Wood92Tianjin University of Science & Technology3导 管 导管是阔叶材中的水分输导组
3、织,它由一系列的导管细胞首尾相连而成; 依导管细胞壁的增厚情况不同,导管细胞可分为五种类型,其形态大小等均随木材品种而异。Chapter 1 The Composition and Structure of Wood93Tianjin University of Science & TechnologyEucalyptus VesselChapter 1 The Composition and Structure of Wood94Tianjin University of Science & TechnologyChapter 1 The Composition and Structure
4、of Wood95Tianjin University of Science & TechnologyChapter 1 The Composition and Structure of Wood96Tianjin University of Science & Technology毛白杨横切面Chapter 1 The Composition and Structure of Wood97Tianjin University of Science & Technology杨木导管Chapter 1 The Composition and Structure of Wood98Tianjin
5、University of Science & Technology尾叶桉导管Chapter 1 The Composition and Structure of Wood99Tianjin University of Science & TechnologyFigure 15. Fibers and a vessel segment of a diffuse- porous hardwood for Populus tremulaChapter 1 The Composition and Structure of Wood100Tianjin University of Science &
6、TechnologyChapter 1 The Composition and Structure of Wood101Tianjin University of Science & TechnologyFigure 16. Fibers and wide and narrow vessel segments of a ring-porous hardwood, Ulmus glabraChapter 1 The Composition and Structure of Wood102Tianjin University of Science & Technology导管细胞的类型环状导管 螺
7、旋导管 梯形导管 网状导管 纹孔导管Chapter 1 The Composition and Structure of Wood103Tianjin University of Science & Technology导管与制浆造纸的关系 导管在阔叶材中是杂细胞,其大小及分布影响 制浆过程中药液的扩散; 有时对纸页的表面性质有不良影响; 导管中常含有侵填体、晶体二氧化硅、钙盐 等。侵填体多的木材,对溶液的浸透性减弱 。Chapter 1 The Composition and Structure of Wood104Tianjin University of Science & Techno
8、logy4. 薄壁细胞及木射线薄壁细胞 木射线薄壁细胞 薄壁细胞 薄壁细胞又称为轴向薄壁细胞Chapter 1 The Composition and Structure of Wood105Tianjin University of Science & Technology薄壁细胞 识别阔叶材的重要特征的方法之一是:阔叶材木薄壁组织发达,在横切面上呈现各种类型分布,颜色比周围的基本组织浅。Chapter 1 The Composition and Structure of Wood106Tianjin University of Science & Technology木射线细胞 一般是径向
9、(成横向)排列的,称为同型射 线,也有部分阔叶树种的上、下部为直立型 的,中间为横向的,异型射线。Chapter 1 The Composition and Structure of Wood107Tianjin University of Science & Technology五、针叶材与阔叶材生物结构的区别Chapter 1 The Composition and Structure of Wood108Tianjin University of Science & Technology项 目针 叶 材阔 叶 材年轮除热带外,多数地区中年 轮界线明显除环孔材和部分半孔材 外,不明显细胞类型细胞种类少,管胞占90 95,此外仅有少量木 射线,结构简单细胞种类多,木纤维含 量低,有导管、木射线 及纵向薄壁细胞,还有 少量的管胞,结构复杂木射线特点一般为单列,且为同型木 射线部分为单列,多数为双 列甚至多列,有同型射 线和异型射线纤维形态 及纹孔较粗且长,纹孔明显又短又细,多数纤维的 纹孔不明显树脂道部分针叶材中有树脂道无树脂道纤维排列 规则性横切面中纤维排列规则性 强,木材结构较均匀受导管影响,纤维排列 规则性不如针叶材,且 不同材种的规则性差别 甚大