Cereal Chem 58:61 - 69.  |  VIEW ARTICLE
Ultrastructure and Cytochemistry of Mature Oat (Avena sativa L.) Endosperm. The Aleurone Layer and Starchy Endosperm.

D. B. Bechtel and Y. Pomeranz. Copyright 1981 by the American Association of Cereal Chemists, Inc. 

The endosperm of five oat cultivars was studied with light and electron microscopy, cytochemistry, and enzymatic digestions. The aleurone was typically composed of a single layer of cells with an occasional area that was two cells thick. Aleurone grains, lipid bodies, plastids, mitochondria, endoplasmic reticulum, and a centrally located nucleus were common in the aleurone cells. Only the aleurone cells contained aleurone grains, which possessed a protein-carbohydrate body that contained inclusions. Cells in the subaleurone starchy endosperm contained numerous protein bodies and a few small starch granules, whereas cells in the central starchy endosperm were composed mostly of starch with protein bodies interspersed. The protein bodies ranged in size from 0.3 to 5 micrometers in diameter and in shape from round to angular to irregular masses. All protein bodies shared a common characteristic: they contained rounded electron-lucent inclusions embedded in a matrix. The protein bodies, particularly those from the subaleurone, were associated with densely stained regions containing ribosomes and endoplasmic reticulum. Simple and compound starch grains occurred in both regions of the starchy endosperm.