Cereal Chem 63:232-240   |  VIEW ARTICLE
A Freeze-Fracture Study of Storage Protein Accumulation in Unfixed Wheat Starchy Endosperm.

D. B. Bechtel and B. D. Barnett. Copyright 1986 by the American Association of Cereal Chemists, Inc. 

A freeze-fracture study of storage protein accumulation was conducted on developing endosperm of hard red winter wheat. Storage protein was observed in the starchy endosperm as discrete membrane-bounded protein bodies about seven days after flowering (DAF). The protein bodies fused with vacuoles and deposited the storage protein into the vacuoles. Also present in the cytoplasm at 7 DAF were numerous Golgi bodies that were apparently connected to large sheets of rough endoplasmic reticulum (RER). Protein bodies were greatly enlarged by 12 DAF and very complex with numerous vesicles associated with their periphery. The RER had changed from large sheets to small cisternal elements that were interconnected by tubular ER. Small vesicles were produced by the ER. By 17 DAF storage protein matrix was evident. The matrix, consisting of large cross-fractured areas of protein, was membrane bounded and in close association to both starch granules and cytoplasm. The matrix enlarged during maturation (19-35 DAF), as did the starch granules, and resulted in isolating the cytoplasm into small regions of the endosperm cell.