The effect of environment on endosperm cell-wall development in Triticum aestivum during grain filling: an infrared spectroscopic imaging study

One of the major factors contributing to the failure of new wheat varieties is seasonal variability in end-use quality. Consequently, it is important to produce varieties which are robust and stable over a range of environmental conditions. Recently developed sample preparation methods have allowed the application of FT-IR spectroscopic imaging methods to the analysis of wheat endosperm cell wall composition, allowing the spatial distribution of structural components to be determined without the limitations of conventional chemical analysis. The advantages of the methods, described in this paper, are that they determine the composition of endosperm cell walls in situ and with minimal modification during preparation. Two bread-making wheat cultivars, Spark and Rialto, were selected to determine the impact of environmental conditions on the cell-wall composition of the starchy endosperm of the developing and mature grain, focusing on the period of grain filling (starting at about 14 days after anthesis). Studies carried out over two successive seasons show that the structure of the arabinoxylans in the endosperm cell walls changes from a highly branched form to a less branched form. Furthermore, during development the rate of restructuring was faster when the plants were grown at higher temperature with restricted water availability from 14 days after anthesis with differences in the rate of restructuring occurring between the two cultivars

Wheat Cell Wall Polysaccharides (Dietary Fibre)

Wheat is a major source of dietary fibre in the human diet, with whole grain containing about 11–15% fibre/g dry wt. However, in most countries wheat is most widely consumed after milling to give white flour, reducing the fibre content to less than 5%. The major dietary fibre components in white flour are the cell wall polysaccharides arabinoxylan and β-glucan. This chapter therefore focuses on these components, reviewing their structures and properties, biosynthesis, variation in amount and composition and genetic control. This provides a basis for increasing the content of wheat fibre and manipulating its properties to optimise the health benefits of wheat-based foods