Philippe Sully, Robert Paul, Barron Cécile, Saulnier Luc, Guillon Fabienne
Unité de Recherches Biopolymères, Interactions et Assemblages, INRA, BP 71627, 44316 Nantes, France.
J Agric Food Chem. 2006 Mar 22;54(6):2303-8. doi: 10.1021/jf052922x.
The time course and pattern deposition of the cell wall polysaccharides in the starchy endosperm of wheat (Triticum aestivum cv. Recital) during grain development was studied using Fourier transform infrared microspectroscopy (micro-FTIR). Three stages of grain development identified as key stages for cell wall construction were retained as follows: the end cellularization, the beginning of cell differentiation, and the beginning of maturation. Micro-FTIR revealed that beta-(1-->3),(1-->4) glucans and arabinoglactan proteins are the main cell wall components of endosperm at the end of the cellularization stage, whereas arabinoxylans (AX) appeared only at the cell differentiation stage. Past the differentiation stage, FTIR spectra were dominated by AX features. Cell walls at the beginning of cell differentiation and at endosperm maturation could be distinguished by spectral features that were ascribed to AX substitution. AX appeared more substituted at the beginning of cell differentiation. Moreover, a difference in the degree of AX substitution was found between peripheral and central parts of the grain at the cell differentiation stage; AX in central cells was less substituted. Thus, dramatic changes in endosperm cell wall composition were detected during wheat grain development with respect to both the relative occurrence of individual constituents and the fine structure of the AX.
利用傅里叶变换红外光谱显微镜（显微傅里叶变换红外光谱）研究了小麦（普通小麦品种Recital）籽粒发育过程中淀粉质胚乳细胞壁多糖的时间进程和沉积模式。确定了籽粒发育过程中细胞壁构建的三个关键阶段，具体如下：细胞化末期、细胞分化初期和成熟初期。显微傅里叶变换红外光谱显示，β-(1→3),(1→4)葡聚糖和阿拉伯半乳聚糖蛋白是细胞化末期胚乳细胞壁的主要成分，而阿拉伯木聚糖（AX）仅在细胞分化阶段出现。在分化阶段之后，傅里叶变换红外光谱以阿拉伯木聚糖特征为主。细胞分化初期和胚乳成熟时的细胞壁可通过归因于阿拉伯木聚糖取代的光谱特征来区分。在细胞分化初期，阿拉伯木聚糖的取代程度更高。此外，在细胞分化阶段，籽粒外周和中部的阿拉伯木聚糖取代程度存在差异；中央细胞中的阿拉伯木聚糖取代程度较低。因此，在小麦籽粒发育过程中，胚乳细胞壁组成在单个成分的相对含量和阿拉伯木聚糖的精细结构方面都发生了显著变化。
