Three-Dimensional Reconstruction of a Dictyosome using Serial Sections

A single dictyosome from a suspension cultured sycamore cell has been reconstructed on an enlarged scale using electron micrographs obtained from a series of 12 thin sections as the basis for the moulding of profile slices. Slices were hardened and stuck together to form single cisternae, tubules and vesicles. These structural elements were joined, true-to-scale, to give a three-dimensional figure. The model thus obtained is more realistic than other well-known dictyosomal models previously presented in the literature. In contrast to these our model exhibits occasional membrane continuities between adjacent cisternae of the dictyosomal stack and entertains the possibility of similar connections between cisternae of the endoplasmic reticulum and the Golgi apparatus.