天然棉纤维表面超微结构及其变化的定量分析

天然棉纤维为异质性生物大分子，其超分子结构复杂. 通过对棉纤维细胞壁横切面的微观分析，发现其结构单元主要是微纤丝，异质性棉纤维超分子结构主要是微纤丝聚集排列方式的变化造成的. 利用原子力显微镜（AFM）对棉纤维表面立体结构的直接观察分析也进一步确证微纤丝聚集排列方式的多样性. AFM获得的结构图像是三维立体的，其起伏变化的指标——表面粗糙度，能够定量地表征棉纤维表面超微结构（微纤丝交叉区与平行区）及其降解过程中的变化程度. 对比X光衍射（XRD），红外光谱（FTIR）等跟踪棉纤维结构的变化结果，AFM对表面超微结构的分析能够在更深层次上反映具体结构的变化规律，从而为解决异质性的纤维素超分子结构与酶解效率之间定量关系的研究奠定了基础.

Quantitative analysis of the ultrastructure of native cotton fibre surface and its changes——Surface roughness of ultrastructure determined by AFM

The examinations of cotton cell walls by atomic force microscopy show that the supermolecular structure is heterogeneous, and the cotton fibres contain microfibrils which are the main structural units of cell walls. These microfibrils are arranged in two fashions, one is cross fashion, and the other is parallel fashion. These arrangements are more orderly than those in the other plant cell walls. Partial hydration of cell walls indicates that the sensitivity of microfibrils to the crude cellulase differs in different arrangement fashions. The examination by AFM indicates that the inhomogeneous ultrustructure of microfibrils and the different arrangement fashions of microfibrils cause the heterogeneousness of cotton fibres. Surface roughness, a statistic parameter for whole surface structure, can be a criterion to measure and monitor the ulturastructure and their changes combining with XRD and FTIR results.