Ultrastructure of contact zone between epidermis and mesophyll.
TEM image of material postfixed in osmium tetroxide, embedded in SPI 812, and viewed in transverse section. Shown are the proximal ends of two epidermal cells (ec) bordering three mesophyll cells (mc) and associated intercellular spaces (is). Thickenings of Igersheim (ti) are restricted to the walls of the inner tangential walls of the epidermal cells; the thickenings may affect only certain parts of the wall. Note single plasmodesma (pd) (compare Figure 10) in the thickening of Igersheim. Vacuoles of mesophyll cells filled with numerous osmiophilic droplets.