Authors: Zehra GENÇ
Abstract: The nectaries of Euphorbia pulcherrima Willd., E. milii Des Moulins, E. fulgens Kraw., E. pseudocactus Berger, E. desmondii Keay et Milne Redhead and E. stapfii Berger are investigated using an electron microscope. There are secretory pits in the epidermis and passage cells which are covered with a thin cuticle that allows the exudation of nectar. Although the other epidermis cells have a similar fine structure, they are covered with a thick cuticle which is highly folded in some species. Golgi apparatus seems to be active only in the E. pulcherrima and less distinctly in the E. milii nectaries. In the epidermis cells of E. pulcherrima and E. fulgens, a well-developed endoplasmic reticulum is seen. In the other glands, there are no or very few structural indications of a direct participation of the nectary cells in the synthesis and active transmembrane transport of nectar components. It is concluded that the main route of prenectar is the apoplast, and that the glands of different species differ in their role during nectar secretion. Various cytoplasmic and vacuolar inclusion bodies are described.
Keywords: Euphorbia L., Nectaries, Electron microscope