Figure 1.

Light micrographs of toluidine-blue-stained sections through barley grains during endosperm differentiation. A, At 10 DAP several cell layers of maternal tissue surround the brick-like arrangement of cells distinguishing the differentiating aleurone layers from the starch-rich central endosperm. Bar = 200 μm. B, At 14 DAP a subaleurone cell layer marked by small starch granules and protein bodies lies between the aleurone cell layers and starchy endosperm. Bar = 100 μm. C, By 22 DAP the aleurone cells appear to have fully differentiated with their cell walls attaining maximum thickness whereas large endosperm cells continue to accumulate starch. Bar = 100 μm. al, Aleurone; se, starchy endosperm; sa, subaleurone.