https://scholars.lib.ntu.edu.tw/handle/123456789/633645
標題: | Wood cellulose microfibrils have a 24-chain core-shell nanostructure in seed plants | 作者: | Tai, Hwan-Ching Chang, Chih-Hui Cai, Wenjie Lin, Jer-Horng Huang, Shing-Jong Lin, Qian-Yan Yuan, Eric Chung-Yueh Li, Shu-Li YING-CHUNG LIN CHUN-CHUNG CHAN Tsao, Cheng-Si |
公開日期: | 22-六月-2023 | 出版社: | Nature Research | 卷: | 9 | 起(迄)頁: | 1154–1168 | 來源出版物: | Nature plants | 摘要: | Wood cellulose microfibril (CMF) is the most abundant organic substance on Earth but its nanostructure remains poorly understood. There are controversies regarding the glucan chain number (N) of CMFs during initial synthesis and whether they become fused afterward. Here, we combined small-angle X-ray scattering, solid-state nuclear magnetic resonance and X-ray diffraction analyses to resolve CMF nanostructures in native wood. We developed small-angle X-ray scattering measurement methods for the cross-section aspect ratio and area of the crystalline-ordered CMF core, which has a higher scattering length density than the semidisordered shell zone. The 1:1 aspect ratio suggested that CMFs remain mostly segregated, not fused. The area measurement reflected the chain number in the core zone (Ncore). To measure the ratio of ordered cellulose over total cellulose (Roc) by solid-state nuclear magnetic resonance, we developed a method termed global iterative fitting of T1ρ-edited decay (GIFTED), in addition to the conventional proton spin relaxation editing method. Using the formula N = Ncore/Roc, most wood CMFs were found to contain 24 glucan chains, conserved between gymnosperm and angiosperm trees. The average CMF has a crystalline-ordered core of ~2.2 nm diameter and a semidisordered shell of ~0.5 nm thickness. In naturally and artificially aged wood, we observed only CMF aggregation (contact without crystalline continuity) but not fusion (forming a conjoined crystalline unit). This further argued against the existence of partially fused CMFs in new wood, overturning the recently proposed 18-chain fusion hypothesis. Our findings are important for advancing wood structural knowledge and more efficient use of wood resources in sustainable bio-economies. |
URI: | https://scholars.lib.ntu.edu.tw/handle/123456789/633645 | ISSN: | 2055-0278 | DOI: | 10.1038/s41477-023-01430-z |
顯示於: | 生命科學系 |
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