The effect of dehydration of plant cell walls on the physical status of cellulose microfibrils (CMFs) interspersed in pectin matrices was studied. Vibrational sum frequency generation (SFG) spectroscopy analysis of cellulose revealed reversible changes in spectral features upon dehydration and rehydration of onion epidermal walls used as a model primary cell wall (PCW). Combined with microscopic imaging and indentation modulus data, such changes could be attributed to local strains in CMFs due to the collapse of the pectin matrix upon dehydration. X-ray diffraction (XRD) showed that the (200) spacing of cellulose in dried PCWs is larger than that of cellulose Iβ obtained from tunicates. Thus, the modulus of CMFs in PCWs would be lower than those of highly-crystalline cellulose Iβ and inhomogeneous local bending or strain of CMFs could occur readily during the physical collapse of pectin matrix due to dehydration.

研究了植物细胞壁脱水对散布在果胶基质中的纤维素微纤维（CMF）物理状态的影响。纤维素的振动总和频率生成（SFG）光谱分析表明，在用作模型原代细胞壁（PCW）的洋葱表皮壁脱水和再水化后，光谱特征发生了可逆变化。结合显微成像和压痕模量数据，这种变化可能归因于果胶基质在脱水后的崩塌，从而导致了CMF中的局部应变。X射线衍射（XRD）显示，干燥PCW中纤维素的（200）间距大于从被膜获得的纤维素Iβ的间距。因此，