Grain filling 11 to 16 days

Embryo sac: wall changes


The whole grain at 11days after flowering. Longitudinal section through the ventral groove. Details of the pericarp and the ventral groove can be seen in other images.
The section above viewed in polarized light to identify the presence of starch grains. Polarized light is diffracted in a special way by starch grains.
The longitudinal section of the endosperm shows compartments packed with starch granules. The aleurone cells can now be identified.
The configuration of the nucellus is changing very rapidly. This section was made from a grain at 13 days after flowering. Lipids and proteins within the endosperm stain differently to the starch grains.
The cell layers surrounding the embryo sac start to contact each other. The nucellus becomes progressively compressed as the endosperm packs with starch. This section was cut across the grain (TS) at 16 days after flowering.
This picture of the pericarp, in transverse section, shows that the nucellus has an open structure at 11days after flowering. The nucellus undergoes many changes through grain development. The Cell Layers inside the Grain are described in detail in a separate section.
A detail of the pericarp shows that the individual layers are still distinct at 11days after flowering. The aleurone is almost recognizable. The nucellus has an open structure. This area of the pericarp also has tube cells and cross cells. There are many rapid changes in the configuration of the individual layers of the pericarp at this time. The Cell Layers inside the Grain are described in detail in a separate section.
Longitudinal section through the endosperm and the layers of the pericarp furthest away from the embryo, 11days after flowering. Compare this with an image, below, of the same tissues at 16 days after flowering.
Longitudinal section through the endosperm and the layers of the pericarp furthest away from the embryo, 16 days after flowering. The groove aleurone cells and the tissues of the ventral groove are further developed when compared to the image, above, from 11 days after flowering.