Lignification in cell cultures of Pinas radiata:: activities of enzymes and lignin topochemistry
Lignification in cell cultures of Pinas radiata:: activities of enzymes and lignin topochemistry
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DOI：
10.1093/treephys/26.2.201
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发表时间：
2006-02-01
期刊：
影响因子：
4
通讯作者：
Schmitt, U
中科院分区：
文献类型：
--
作者：
Möller, R;Koch, G;Schmitt, U
对辐射松木质化过程中的酶和局部化学变化进行了研究。Don细胞培养体系诱导分化出具有木质次生细胞壁的管分子和石细胞。木质素相关酶苯丙氨酸解氨酶（PAL; EC www.example.com）和肉桂醇脱氢酶（CAD; EC www.example.com）的活性随着细胞分化而增加，表明酶活性的增加与细胞壁的木质化有关，而不是由胁迫诱导的。这一结果也表明PAL和CAD是针叶裸子植物导管分子分化的合适标记。为了进一步表征木质化在这个细胞培养系统中，细胞紫外-显微分光光度法和硫代酸解。木质素的典型的紫外吸收光谱，从次生细胞壁的导管分子和石细胞，并从化合物的中间层连接分化的细胞，并证实了木质素的存在，通过硫代酸解。导管分子细胞壁中的木质素局部化学特征与辐射松木材的细胞壁相似，如连接相邻细胞的复合中层中木质素浓度较高，次生细胞壁中木质素浓度较低。因此，辐射松细胞培养体系非常适合于研究针叶裸子植物木质部次生细胞壁的形成。
Enzymatic and topochemical aspects of lignification were studied in a Pinus radiata D. Don cell culture system that was induced to differentiate tracheary elements and sclereids with lignified secondary cell walls. The activities of the lignin-related enzymes phenylalanine ammonia lyase (PAL; EC 4.3.1.5) and cinnamyl alcohol dehydrogenase (CAD; EC 1.1.1.195) increased concomitantly with cell differentiation, indicating that the increase in enzyme activity was related to lignification of the cell walls and was not induced by stress. This result also indicates that PAL and CAD are suitable markers for tracheary element differentiation in coniferous gymnosperms. To further characterize lignification in this cell culture system, cellular UV-microspectrophotometry and thioacidolysis were employed. Typical UV-absorption spectra of lignin were obtained from the secondary cell walls of the tracheary elements and sclereids and from the compound middle lamella connecting differentiated cells, and the presence of lignin was confirmed by thioacidolysis. Certain aspects of lignin topochemistry in the cell walls of the tracheary elements were similar to cell walls of P. radiata wood, such as the high lignin concentration in the compound middle lamella connecting adjacent cells and the lower lignin concentration in the secondary cell walls. Therefore, the P. radiata cell culture system appears to be well suited to study the formation of lignified secondary cell walls in coniferous gymnosperms.