The ultrastructural development of spherosomes and oil bodies in the developing embyro of Crambe abyssinica

Abstract

The development of the cotyledon cells of Crambe abyssinica was studied using the electron microscope. New evidence is presented, concerning the site of origin of the oil body. The spherosomes and oil bodies were found to be separate entities, with different sites of origin and function within the cell. The spherosomes, which were shown to be present in the cell before the onset of oil body formation, and formed from the endoplasmic reticulum, contains acid β glycerophosphatase. At least one of its functions is to supply a hydrolytic enzyme to the vacuoles in which the alcurone grains subsequently develop. Oil bodies were found to develop from small areas of particulate material in the cytoplasm 8–10 days after petal fall, and their function appears to be as sites of an oil storage product (triglyceride), which is synthesised during seed development. The development of the protein body is also briefly discussed.