The endosperm cavity of wheat grains contains a highly hydrated gel of arabinoxylan

Abstract

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Exploring the Developmental Progression of Endosperm Cavity Formation in Maize Grain and the Underlying Molecular Basis Using X-Ray Tomography and Genome Wide Association Study

“…It is worth noting that the EC described here is different from that of the EC in wheat. The latter is designated as a gap between the endosperm and the maternal tissue ( Chateigner-Boutin et al, 2021 ) from which nutrients are taken up by the filial tissues. By contrast, the EC in maize grain represents a hollow space within the basal region of the endosperm ( Figure 1A ).…”

Synchrotron Based X-ray Microtomography Reveals Cellular Morphological Features of Developing Wheat Grain

“…The only detail of the inside of cells revealed by X-rays is the presence of starch grains in the endosperm that are particularly highlighted due to their high density. The endosperm cavity, which contains water, proteins, and carbohydrates, is visible in the ventral crease region although its shape appears different than in microscopy images of grain sections where it is altered and emptied by preparation steps (Figure 5B,D) [21]. At 100 • DAA (Figure 5A), apart from pericarp tissues, fewer internal tissues are distinguished in the X-ray images probably because their developing cell walls are thinner and because the wheat grains are more highly hydrated (75% and 68% at 100 • DAA and 250 • DAA respectively).…”

“…Other imaging modalities provide information that would be of interest to relate to the ones obtained from X-ray tomography and microscopy. For example, magnetic resonance imaging gives access to local water status within the grain (e.g., for wheat [21]) but scans are very time-consuming, and spatial resolution is still low (cellular level cannot be reached). Mass-spectrometry imaging reveals chemical composition within tissues with improved discrimination power (e.g., for wheat [41]).…”

“…The acquisition by optical or electron microscopy of a large number of serial sections, followed by a registration process, can lead to the reconstruction of the 3D anatomy [15][16][17][18]. Magnetic resonance imaging is a non-destructive imaging technique that can be used to analyze both the anatomy and the functions of plant tissues at the organ scale [19][20][21]. The resolution is however limited to a few dozens of microns, making it difficult to investigate thin tissues or cell organization.…”

Exploiting Rye in Wheat Quality Breeding: The Case of Arabinoxylan Content

“…Finally, at 28 DAA, the cell walls of the entire endosperm tissue could be distinctly labelled [ 55 ]. Recent research on wheat showed that AX is also found in intracellular vesicles in various grain regions: in the apoplast between the nucellar epidermis and the endosperm tissues, and in the endosperm cavity [ 56 ]. The endosperm cavity separates the nucellar projection from the endosperm transfer cells and it is filled by a viscous, gel-like substance that persists even after desiccation [ 56 , 57 ].…”