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    李昕, 李姗, 邓丽萍, 李仁, 殷亚方, 郑景明. 楸树木质部水分输导组织构造特征的轴向变化[J]. 北京林业大学学报, 2020, 42(1): 27-34. DOI: 10.12171/j.1000-1522.20190238
    引用本文: 李昕, 李姗, 邓丽萍, 李仁, 殷亚方, 郑景明. 楸树木质部水分输导组织构造特征的轴向变化[J]. 北京林业大学学报, 2020, 42(1): 27-34. DOI: 10.12171/j.1000-1522.20190238
    Li Xin, Li Shan, Deng Liping, Li Ren, Yin Yafang, Zheng Jingming. Axial variation of characteristics of water conducting tissue in xylem of Catalpa bungei[J]. Journal of Beijing Forestry University, 2020, 42(1): 27-34. DOI: 10.12171/j.1000-1522.20190238
    Citation: Li Xin, Li Shan, Deng Liping, Li Ren, Yin Yafang, Zheng Jingming. Axial variation of characteristics of water conducting tissue in xylem of Catalpa bungei[J]. Journal of Beijing Forestry University, 2020, 42(1): 27-34. DOI: 10.12171/j.1000-1522.20190238

    楸树木质部水分输导组织构造特征的轴向变化

    Axial variation of characteristics of water conducting tissue in xylem of Catalpa bungei

    • 摘要:
      目的本文拟探究楸树木质部边材解剖结构的轴向变化规律,为深入理解阔叶树种的水分传导机制提供参考,并为楸树人工林的栽培、中国特有温带珍贵优质用材树种的保护及木材利用提供理论依据。
      方法以3株楸树为研究对象,自基部向上采集树干0、1.3、3.8、6.3、8.8、11.3 m共6个高度处的边材样品,分别测量边材面积、制备横向及弦向显微切片,并利用光学显微镜观察测量导管腔直径、导管密度等木质部解剖结构特征,利用相关性分析、方差分析研究木质部解剖特征间的相互关系,利用线性回归分析研究木质部解剖特征的轴向变化规律。
      结果(1)早材导管腔直径、早晚材导管密度随高度变化不显著,但早材导管腔直径随取样高度增加有减小趋势,导管密度则有相反趋势。最大早晚材导管腔直径、晚材导管腔直径、纹孔膜直径随树高增加而显著减小。(2)随树高增加,边材面积与导管水力直径均显著减小。(3)边材面积、纹孔膜直径均与导管水力直径呈显著正相关。
      结论楸树木质部水分疏导组织构造特征的轴向变化主要表现在边材面积、导管特征和纹孔膜特征3个方面。楸树生长轮明显,早晚材导管腔直径差异较大,早材比晚材变异幅度更大。最大导管腔直径的轴向变化显著,导管密度的轴向变化不显著,边材面积和纹孔膜直径的轴向变化显著。综合来看,楸树基部导管相对大而疏,边材面积大,上部导管相对小而多,边材面积小。这是楸树木质部结构适应长距离输水功能的一种优化设计,以降低树木栓塞化风险,提高水分运输的效率和安全性。

       

      Abstract:
      ObjectiveThis paper intends to explore the axial variation of the anatomical structure of wood sapwood of Catalpa bungei, in order to deepen our understanding of the water conduction mechanism in broadleaved tree species, as well as to provide theoretical basis for the cultivation of C. bungei plantation, the protection of this precious tree species and the utilization of its wood.
      MethodThree trees of C. bungei were selected, sapwood samples were collected from tree height at 0, 1.3, 3.8, 6.3, 8.8 and 11.3 m, respectively. Meanwhile, sapwood area was measured, transverse and longitudinal sections of wood blocks were prepared. The anatomical traits of xylem such as vessel lumen diameter, vessel frequency were observed with light microscopy. Relationships among wood anatomical traits were tested by correlation analysis and analysis of variance, and axial changes of wood anatomical traits were analyzed by linear regression.
      Result(1) Earlywood vessel lumen diameter and vessel density do not change significantly with tree height, however, earlywood vessel lumen diameter decreased with height while vessel density had an opposite trend. Maximum vessel lumen diameter of early- and latewood, latewood vessel lumen diameter and pit membrane diameter varied significantly with tree height, which decreased with tree height. (2) Both sapwood area and hydraulic vessel diameter decreased significantly with tree height. (3) Both sapwood area and pit membrane diameter were significantly positively correlated with the hydraulic vessel diameter.
      ConclusionAxial variance of hydraulic structure of C. bungei is manifested in three aspects: sapwood area, vessel related traits and pit membrane properties. Growth ring of C. bungei was obvious, and the early and late vessel lumen diameter wood differed greatly with bigger variation of early wood than that of late wood. Axial variation of the maximum vessel lumen diameter, sapwood area and pit membrane diameter are significant for this tree species whereas axial variation of the vessel density is not significant. Taken together, wood at the base of C. bungei owned relatively large and sparse vessels and higher proportion of sapwood area compared to many small vessels and lower proportion of sapwood area in wood at the upper stem, and this architecture is an optimized structural design for the long-distance water transport function during xylem evolution, leading to reduction of embolization risk and improvement of efficiency and safety of water transport.

       

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