基于细胞壁多层结构结合界面弱化分析的竹材材质衰退机理研究

Bamboo has unique growth characteristics, that is fast growth and early material deterioration, which has an important influence on the cultivation and utilization of bamboo. Bamboo has no secondary growth, relying on the rapid thickening and lignification of multilayered structure to achieve rapid material generation, but what change will happen on the multilayered structure after full development of bamboo and what cause material degradation is still unclear. This project starts with the change of component accumulation and mechanical properties of multilayered structure based on the basic principle of bonding interface theory of composites, and the synergistic changes of cell wall structure, chemical composition and mechanical properties during bamboo aging will be systematically analyzed by using advanced microscopic spectroscopy (laser confocal raman microscopy, nano infrared technology) and cell wall mechanics (nanoindentation technology, nano dynamic mechanical analysis technology ) testing techniques. The degradation process of bonding interface in the multilayered structure of cell wall and its relationship with cell life activities will be explored, and the intrinsic nature of material degradation in late stage of bamboo growth will be revealed from the view of bonding interface theory and biology. The research results will deepen the understanding of the physical and chemical properties of bamboo cell wall, reveal the material degradation mechanism of bamboo, and provide theoretical reference for the rational management of bamboo forest and the high value utilization of bamboo.

竹子具有成材速度快，材质劣化早的材质生长特点，对竹林培育和竹材利用具有重要影响。竹子没有次生生长，依靠多壁层结构的快速增厚和木质化实现材质的快速生成，但已经生成的多壁层结构在竹子发育成熟以后如何变化引起材质的衰退仍不清楚。本项目借鉴复合材料结合界面理论的基本原理，从细胞壁多层结构的组分累积和力学性质变化入手，采用先进的显微光谱（激光共聚焦拉曼显微技术、纳米红外技术）和细胞壁力学（纳米压痕技术、纳米动态力学分析技术）测试手段，系统分析竹子老化过程中纤维细胞壁层结构、化学组成及力学性质的协同变化，探究细胞壁多层结构结合界面的弱化过程及其与细胞生命活动的关系，从界面结合理论以及生物学的角度揭示竹子生长后期茎秆材质衰退的内在本质。研究成果将进一步加深对竹材细胞壁多层结构理化性质的认识，揭示竹材材质的衰退机理，为实现竹林的合理经营及竹子的高值化利用提供理论参考。

竹子具有成材速度快，材质劣化早的生长特点，对竹林培育和竹材利用具有重要影响。本项目以毛竹为研究材料，深入研究了毛竹材质的衰退过程，从细胞生命活动和结合界面弱化的角度探索了毛竹材质衰退的内在机理。采用ELISA检测试剂盒技术，在组织层面上揭示了竹材细胞生物活性的变化过程。采用组织染色和木材解剖技术，揭示了竹材材质衰退过程中的细胞构造变化。利用湿化学分析法、电感耦合等离子光谱（ICP-OES）技术获得了毛竹细胞壁化学组分含量的变化规律，采用红外光谱、X射线衍射、离子色谱等方法，揭示了细胞生命活动对竹材细胞壁化学成分组成结构的影响；利用纳米压痕技术解译了竹材细胞结合界面的弱化过程；利用激光共聚焦拉曼显微光谱技术获得了竹材材质衰退过程中细胞壁结合界面化学成分的变化规律。多种手段的研究结果表明，竹材细胞的死亡是一个漫长的过程，其生命活动引起细胞结合界面的化学组成发生改变，导致界面结合性能弱化，进而引起竹材材质衰退。本项目借鉴复合材料结合界面理论和生物学的基本原理，从细胞结合界面的组分累积和力学性质变化揭示了竹材材质衰退的机理，将进一步加深了对竹材材质生长过程的认识，为竹林的合理经营及竹子的高值化利用提供理论参考。