Grain filling 17 to 21 days

Endosperm micrographs


Cell division ceases in the endosperm at about 21 days after flowering. The compartments produced within the endosperm will pack with starch from now until dry down. Some parts of the outer epidermis have started to make contact with the cell layers close to the endosperm.
Type 'A' and Type 'B' starch grains in the outer endosperm close to the aleurone layer. The smaller ones are the type B starch grains. They are not produced until cell division in the endosperm has stopped.
Type 'A' and Type 'B' starch grains diffract polarized light producing a characteristic 'Maltese Cross'. (This is the same section as above.)
The endosperm is now clearly divided into compartments which are rapidly packing starch grains. The aleurone layer surrounds the endosperm and the other layers start to bind together.
The aleurone cells are now firmly fixed between the starch filled cells of the outer endosperm and the thick walls of the nucellar epidermis. The Cell Layers inside the Grain are described in detail in a separate section.