Intratissular Secretion

Abstract

Idioblasts are single secretory cells. They are secretory structures of a simple type. The evolution of secretory structures is proposed (Fahn 1979) to go from scattered cells, idioblasts, to organized intratissular canals, ducts, and cavities covered by epithelial cells and to end on the glands located on the plant surface. Two main types of secretory tissues can be distinguished depending on origin and localization: secretory tissues that are located within the plant and secrete substances into the intra- or intercellular spaces of plant, and secretory structures that are located on the plant surface and secrete compounds directly out onto the plant surface. The first type of secretion will be dealt with in the present chapter and the second will be described in Chapter 3.