micropillars reveal ultrastructural anisotropy Hygroscopic swelling and shrinkage of latewood cell wall
micropillars reveal ultrastructural anisotropy Hygroscopic swelling and shrinkage of latewood cell wall
复制标题
微柱揭示超微结构的各向异性 晚材细胞壁的吸湿膨胀和收缩
DOI：
10.1007/s10086-006-0815-2
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发表时间：
2014
影响因子：
2.9
通讯作者：
D. Derome
中科院分区：
文献类型：
--
作者：
J. Carmeliet;A. Rafsanjani;M. Stiefel;K. Jefimovs;R. Mokso;D. Derome
本研究探讨如何煮沸和干燥处理的影响，张力木材与凝胶状纤维（G-纤维）的29岁Zelkovabranch的各种物理性质。通过煮沸处理，具有大量G-纤维的拉伸木材在纵向方向上显著收缩，并且尽管在水饱和条件下，纵向杨氏模量降低。干燥处理导致绿色抗拉材和含有大量G纤维的水煮抗拉材纵向收缩，并增加了它们的纵向杨氏模量。这些特定的行为在拉伸木材中的G-纤维的比例在一个标本中高度相关，可能是由纤维素微纤丝（CMF）的凝胶层（G-层）的微观行为。由于干燥的拉伸木材的纵向收缩表明存在一个湿敏，非结晶区的CMF，这是丰富的G层。此外，在CMF的非晶区软化在煮沸处理，导致在拉伸木材的纵向杨氏模量的降低。含G纤维的受拉材在沸腾条件下的纵向收缩可能是由于绿色G层中残留的拉伸生长应力所致。然而，无论G-纤维的比例如何，煮沸和干燥处理对拉伸木材中纤维素晶体的004 d间距都没有影响。
This study examined how boiling and drying treatments influenced various physical properties of the tension wood with gelatinous fibers (G-fibers) of a 29-yearoldZelkovabranch. By boiling treatment, tension wood with numerous G-fibers contracted considerably in the longitudinal direction and the longitudinal Young’s modulus decreased in spite of the water-saturated condition. The drying treatment caused green tension wood and boiled tension wood with numerous G-fibers to shrink longitudinally and increased their longitudinal Young’s moduli. These specific behaviors in tension wood were highly correlated with the proportion of G-fibers in a specimen and were probably caused by the microscopic behavior of cellulose microfibril (CMF) in the gelatinous layers (G-layers). The longitudinal shrinkage of tension wood due to drying suggests the existence of a hygro-sensible, noncrystalline region in the CMF, which is abundant in the G-layer. Furthermore, the noncrystalline region in the CMF softens during boiling treatment, resulting in the reduction of the longitudinal Young’s modulus in tension wood. The longitudinal contraction of tension wood with G-fibers by boiling might be caused by the tensile growth stress remaining in green G-layers. However, no changes were detected in the 004d-spacing of cellulose crystal in tension wood from the boiling and drying treatments, regardless of the proportion of G-fibers.