The Fine Structure of the Developing Euphorbia dulcis Endosperm

Euphorbia dulcis has a nuclear type of endosperm which laterbecomes cellular. During the coenocytic period, the Golgi apparatusconsists of moderately proliferating dictyosomes. The endoplasmicreticulum is large, rough and manifests as long cisternal profileswhich are scattered singly or packed in parallel multiple arrays.The mitochondria exhibit different numbers of small cristaeand frequent outline constrictions suggesting approaching binaryfission. The plastids have only slightly structured stromataand contain little or no starch; like the mitochondria, manyof them have indented profiles. Wall formation is seen as chain-like aggregates of coalescingdictyosome vesicles with much associated endoplasmic reticulum.The latter is discussed in terms of cisternal shape, generalthree-dimensional form and probable involvement in trappingGolgi derivatives. The newly constituted cells are highly vacuolateelements having large populations of free ribosomes, many immatureplastids and relatively more numerous mitochondria. Opaque (lipid)bodies are found in the neighbourhood of the plasmalemma. Theendoplasmic reticulum is granular. The presence of a micropylar network of labyrinthine ingrowthsstudding the boundary wall of the coenocytic endosperm is alsodescribed. Euphorbia dulcis, endosperm, ultrastructure, wall ingrowths