共聚焦拉曼显微光谱技术可有效用于木质纤维生物质细胞壁的区域化学研究。利用该技术探索稀酸预处理过程中奇岗纤维细胞壁木质素和羟基肉桂酸的区域化学变化规律。研究发现预处理前木质素在细胞壁各区域的浓度不同，木质素浓度较高的区域羟基肉桂酸的浓度也较高。稀酸预处理后1600 cm－1（木质素）和1170 cm－1（羟基肉桂酸）的峰值强度降低，表明二者被部分溶出，且溶出率为次生壁＞复合胞间层＞角隅胞间层。预处理过程中次生壁和复合胞间层的特征峰强度比值（I 1170／I 1600）呈现上升趋势，表明在这两个形态区域中木质素比羟基肉桂酸更易溶出；而在角隅胞间层没有明显变化，表明该形态区域对二者的溶出没有倾向性。通过本研究可以更加深入了解稀酸预处理中化学组分在亚细胞水平的变化规律，同时也进一步拓展了拉曼光谱技术在植物细胞壁研究领域的应用。%Confocal Raman microspectroscopy (CRM)represents a powerful technique that can provide insights into topochemis-try in lignocellulosic biomass cell wall.In this work,CRM was used to explore the impact of dilute acid (DA)pretreatment on the topochemistry of lignin and hydroxycinnamic acid (HCA)in the fiber cell walls of Miscanthus× giganteus internode.Raman spectra extracted from different morphological regions of untreated fiber cell walls indicated the heterogeneous concentration of lignin and HCA.There is a companied trend between them,that is,regions where there is the higher lignin concentration have the higher concentration of HCA.When treated with DA,it was found that the intensity of 16 00 cm-1 (lignin)and 1 170 cm-1 (HCA)were decreased,which could be contributed to the partially removal of lignin and HCA.The removal rate in different morphological areas followed the decreasing order:secondary cell wall (SW)> compound middle lamella (CML)> cell corner middle lamella (CCML).The increase of the Raman band intensity ratio (1 170/1 600)indicated the preferential removal of lig-nin in the SW and CML as a result of DA pretreatment,while the constant of the ratio meant there is no preference between lig-nin and HCA in the CCML.The research will provide the deep understanding of the topochemistry of lignin and HCA at sub-cel-lular level during DA pretreatment,meanwhile,it also expands the application of Raman spectra in the research area of plant cell wall.
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