Scanning Electron Microscopy of Wheat Starch. III. Granule Development in the Endosperm

Study of A type starch granules from immature wheat endosperm with the scanning electron microscope has led to a developmental sequence being suggested. Evidence is provided which indicates that the initial minute spherical granule becomes a “nucleus” which is progressively surrounded in the equatorial plane by a continually enlarging structure which resembles two lips with a furrow between them. When the lips have completely surrounded the “nucleus” the thickness and diameter of the granule continue to increase in such a way that the furrow becomes shallower and is present in the mature biconvex structure only as a shallow score.