金丝楸木材化学成分的不均一性  

Chemical Composition Heterogeneity of Catalpa bungeana Wood

作　　者：杨昇 李改云[1] Yang Sheng;Li Gaiyun(Hunan Collaborative Innovation Center for Effective Utilizing of Wood & Bamboo Resources Research Institute of Wood Industry, CAF Beijing 100091)

机构地区：[1]中国林业科学研究院木材工业研究所木竹资源高效利用湖南省高校2011协同创新中心,北京100091

出　　处：《林业科学》2021年第1期169-177,共9页Scientia Silvae Sinicae

基　　金：中央级公益性科研院所基本科研业务费专项资金“珍贵阔叶树心边材结构与性质对加工利用的影响机制”(CAFYBB2017ZX003)。

摘　　要：【目的】研究金丝楸木材化学成分在纵向不同高度及径向心、边材中的含量和组成特点,为金丝楸木材加工利用提供科学依据。【方法】分析金丝楸木材纵向不同高度心、边材苯醇抽提物、聚糖和木质素含量,采用细胞壁全溶法结合二维异核单量子核磁共振(2D HSQC NMR)技术对相应部位的原生木质素分子结构进行表征。【结果】金丝楸木材边材苯醇抽提物含量高于心材,且心材中靠近树心部分的苯醇抽提物含量高于靠近边材部分。心、边材苯醇抽提物化学成分存在差异,但不同高度相同径向区域苯醇抽提物含量及其成分差异较小且并未随树高不同体现出特定变化规律。边材木质素含量低于心材,但心、边材木质素含量在树高方向上无明显变化规律。金丝楸木材木质素为典型G/S型木质素,纵向不同高度区域木质素大分子结构基本一致,但心材木质素分子结构中β-5′连接的相对含量高于边材。木聚糖是金丝楸木材半纤维素的主要组分。边材聚糖相对含量高于心材,但心、边材聚糖含量并未随树高不同体现出特定变化规律。【结论】金丝楸木材径向心、边材化学成分含量及相应成分分子结构具有规律性差异,边材向心材过渡过程中主要变化为木质素成分的积累和发色物质的生物合成。木材纵向不同高度相应区域中各化学成分含量也存在一定差别,但并未随树高不同发生规律性变化。木材纵向不同高度相同径向区域中各组分的化学成分和分子结构基本一致。对金丝楸木材进行加工利用时,应重点关注其径向方向的化学成分含量和性质差异。【Objective】This study was carried out with the aim to provide scientific bases for the wood processing and utilization of Catalpa bungeana wood through the characterization of the heterogeneity of chemical compositions in various heights and radial regions.【Method】The contents of benzyl alcohol extracts,polysaccharides and lignin of the heartwood and sapwood at various heights of C.bungeana wood were analyzed.The structural features of the lignin in the corresponding regions were also characterized through whole cell wall dissolving system combined with two-dimensional heteronuclear single-quantum coherence NMR technique.【Result】The contents of the benzyl alcohol extracts in sapwood of C.bungeana wood were higher than those in the heartwood.More extracts were found in the heartwood near the sapwood compared with those in the heartwood near the tree heart.There were some differences in the chemical compositions of the extracts between the sapwood and heartwood of C.bungeana.However,no relationship could be found between the extract contents and tree heights,and the differences in extract content between sapwood and heartwood at different heights were identical.The lignin content in sapwood of C.bungeana was lower than that in heartwood.However,no relationship could be found between the lignin contents and heights.The lignin of C.bungeana wood was made up of guaiacyl(G)and syringyl(S)phenylpropane units.The molecular structure of the lignin at various heights of the C.bungeana wood was similar with each other.However,moreβ-5′linkages could be found in the lignin of the heartwood as compared with the lignin of the sapwood.Xylan was the predominant polysaccharide in hemicelluloses of the C.bungeana wood.The content of the polysaccharides in sapwood was higher than that in heartwood.However,no obvious differences in the content of the polysaccharides in the wood obtained from various heights.【Conclusion】There were obvious differences in content and molecular structure of the chemical compositions be

关 键 词：金丝楸木材 化学组成 抽提物 木质素 分子结构 不均一性 

分 类 号：S781.41[农业科学—木材科学与技术]