黄藤细胞壁木质素区域化学分子光谱成像研究

发布时间：2018-03-17 17:50

本文选题：木质素　切入点：微区分布　出处：《光谱学与光谱分析》2017年10期 　论文类型：期刊论文

【摘要】：整合共聚焦显微荧光和拉曼光谱成像技术系统研究了黄藤藤茎组织中不同类型细胞以及同一细胞不同形态区域的木质素区域化学特点。共聚焦荧光成像表明黄藤藤茎组织中木质素主要汇聚于初生木质部导管、次生木质部导管、维管束间的薄壁组织细胞以及纤维细胞角隅区。基于荧光光谱差异的光谱成像线性拆分结果显示纤维细胞次生壁由宽、窄层交替的同心层状结构组成,且窄层具有更高的木质化程度。比较黄藤、毛竹、芒草、毛白杨和虎皮松拉曼光谱发现黄藤材细胞壁拉曼光谱与阔叶木毛白杨类似,证实了黄藤材的化学组成更加趋近于阔叶木毛白杨。对拉曼光谱中木质素特征峰成像进一步揭示出纤维细胞中木质素不均一的分布规律:其中细胞角隅胞间层和复合胞间层的拉曼信号强度最高,表明较高的木质化程度,其次是次生壁中的窄层,而次生壁宽层中拉曼特征峰强度最低,这一分布规律与竹材纤维细胞中木质素分布规律类似。宽、窄层中木质素不仅存在浓度上的差异,而且木质素基本结构单元的比例亦不同。采取光谱去卷积的方法排除了碳水化合物的影响,发现窄层中愈创木基(G型)木质素与紫丁香基木质素(S型)比例为0.19,而在宽层中这一比值为0.14,这一结果亦解释了宽、窄层荧光光谱间的差异。该研究结果对探索黄藤细胞壁生物合成及力学响应机制研究具有重要理论指导意义。
[Abstract]:The chemical characteristics of lignin region in different types of cells in stem tissue and different morphological regions of the same cell were studied by integrating confocal fluorescence microscopy and Raman spectroscopy. Lignin in the stem tissue of rattan mainly converges in the primary xylem catheter. Secondary xylem ducts, parenchyma cells between vascular bundles and filamentous corner regions. The results of spectral imaging based on fluorescence spectrum difference showed that the secondary wall of fibroblasts was composed of concentric lamellar structures with wide and narrow layers alternately. The narrow layer has a higher degree of lignification. Compared with the raman spectra of Rattan, Phyllostachys pubescens, mango, Populus tomentosa and Poplar, it was found that the cell wall Raman spectra of the wood were similar to those of broadleaved Populus tomentosa. It is confirmed that the chemical composition of the wood is closer to that of hardwood Populus tomentosa. The distribution of lignin heterogeneity in fibroblasts is further revealed by the characteristic peak imaging of lignin in Raman spectroscopy: the intercellular layer of the cell horn and the intercellular layer of the cell. The Raman signal intensity of the composite intercellular layer was the highest. The results showed that the intensity of Raman characteristic peak in the broad layer of secondary wall was the lowest, which was similar to that of lignin distribution in bamboo fiber cells, and the distribution of lignin in secondary wall was similar to that of lignin in bamboo fiber cells, the second was narrow layer in secondary wall, and the intensity of Raman characteristic peak in broad layer of secondary wall was the lowest. The concentration of lignin in narrow layer is different, and the proportion of lignin basic structure unit is also different. The effect of carbohydrate is excluded by spectral deconvolution. It is found that the ratio of guaiacol G type) lignin to syringe lignin S type in narrow layer is 0.19, and the ratio in wide layer is 0.14. This result also explains the width. The results of this study have important theoretical significance for exploring the biosynthesis of cell wall and the mechanism of mechanical response.
【作者单位】：国际竹藤中心竹藤科学与技术重点实验室;
【基金】：国际竹藤中心基本科研业务费项目(1632015002) 国家自然科学基金项目(31500497)资助
【分类号】：O657.3;Q944.6

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