Scanning electron microscopical observations of leaf epicuticular waxes and the stomatal complex of satsuma mandarin (Citrus unshiu Marc.).

Abstract

Morphological features of the development of epicuticular waxes and stomatal complexes of leaves in a clone of satsuma mandarin (Citrus unshiuMarc) were examined by scanning electron microscopy. By the early stages of stomatal development the epicuticular waxes in the form of sand or rodlet had already been excreted sporadically on the surface of epidermal walls. The waxes were then crystallized as amorphous platelets on the surface and thereafter the crystalline portion increased with leaf age. The solitary large-sized stomata (giant stomata), surrounded by a number of normal-sized ones were found at intervals over the surface. The density of stomata was lowest at the base of leaf, greatest at the middle, and intermediate at the tip. The substomatal chamber was continuous with the intercellular spaces in the spongy parenchyma. Several pores were observed in the bottom cell wall of the substomatal chamber.