Christiernin M
Department of Fibre and Polymer Technology, Royal Institute of Technology, KTH, 100 44 Stockholm, Sweden.
Plant Physiol Biochem. 2006 Nov-Dec;44(11-12):700-6. doi: 10.1016/j.plaphy.2006.10.012. Epub 2006 Nov 2.
The cambial tissues of a Populus balsamifera, Balsam poplar clone were studied during a growth season. The Klason and acid-soluble lignin contents were determined as well as the carbohydrate monomer distribution and the protein content. Both the phloem and the xylem sides of the cambial region were examined. The samples were analyzed by thioacidolysis and structures of dimeric products were determined by mass spectrometry after desulphuration. Chemical analysis of samples during the growth season was combined with microscopy of embedded specimens that showed the state of cell differentiation at the time of sampling. In spring and early summer, growth is very rapid and the intention was to collect tissue in which exclusively the middle lamella/primary cell wall had begun to lignify. The Klason lignin, protein content and carbohydrate monomer distribution showed that all the specimens from the cambial tissues sampled during a growth season contained predominantly middle lamella and primary walls; except for the developing xylem sampled in August where the carbohydrate composition showed that secondary walls were present. Thioacidolysis showed that the lignin from the cambial tissues had more condensed structures than the lignin from the reference balsam poplar clone wood. More guaiacyl than syringyl units were detected and mass spectrometry showed that the cambial tissues contained more lignin structures with end-groups than the reference sample. These results suggest that lignification in the cambial layer and early developing xylem may take place predominantly in a bulk fashion during the summer.
在一个生长季节中，对香脂杨（Balsam poplar）无性系的形成层组织进行了研究。测定了克拉森木质素（Klason lignin）和酸溶性木质素的含量，以及碳水化合物单体分布和蛋白质含量。对形成层区域的韧皮部和木质部两侧都进行了检查。样品通过硫代酸解进行分析，脱硫后通过质谱法测定二聚体产物的结构。将生长季节期间样品的化学分析与包埋标本的显微镜检查相结合，显微镜检查显示了采样时细胞分化的状态。在春季和初夏，生长非常迅速，目的是收集仅中层薄片/初生细胞壁开始木质化的组织。克拉森木质素、蛋白质含量和碳水化合物单体分布表明，在生长季节采集的形成层组织的所有标本主要包含中层薄片和初生壁；除了8月采集的正在发育的木质部，其碳水化合物组成表明存在次生壁。硫代酸解表明，形成层组织的木质素比参考香脂杨无性系木材的木质素具有更多的缩合结构。检测到的愈创木基单元比紫丁香基单元多，质谱分析表明，形成层组织比参考样品含有更多带有端基的木质素结构。这些结果表明，形成层和早期发育的木质部中的木质化可能在夏季主要以整体方式发生。
