Grain filling 21 to 30 days

Endosperm micrographs


The same section viewed in Darkfield shows the endosperm now packed out with starch.
TS at low power shows that the compression and adhesion of the cuticular layers is position dependant. The cheeks of the grain are the first to adhere; the dorsal surface adheres later. For more information on the layers surrounding the embryo sac go to the special section.
The cells of the aleurone layer have a granular appearance and are embedded in a firm matrix. This granular appearance is the result of the vacuoles filling with protein.
For more information on the changes in these cell layers go to the special section.
The mature endosperm packed with starch grains (viewed at high magnification in polarized light). The larger, type-A, starch granules are lens shaped; the smaller, type - B, which are added after the type- A are spherical.
Here the endosperm has filled out and now meets the surrounding maternal tissues. The prismatic endosperm cells are packed with starch. The larger, type-A, starch granules are lens shaped; the smaller, type - B, which are added after the type- A are spherical. 26 days after flowering.