ORIGIN AND DEVELOPMENT OF SPOROPOLLENIN BODIES

This paper reports the results of a study of the first beginnings of sporopollenin granules in the cells of the tapetum. The endoplasmic reticulum was observed to be the system responsible for their production, first by the formation of electron-dense bodies (pro-Ubisch bodies). These constitute the nuclei of the sporopollenin granules upon which laminae with the characteristics observed in the exine of pollen-grains are deposited in formation of the young Ubisch bodies. The latter ultimately assume a spherical shape (adult Ubisch bodies), whereupon they seem to be carried by channels across the cytoplasm of the tapetum into the locule of the pollen-sac. The origin, development and possible function of sporopollenin granules are discussed in the light of the theories and observations of other authors and of the writers themselves. © 1969 Springer-Verlag.