Fig. 1 Myrciaria glomerata – (A) Branch with opposite leaves; (B) Detail of the abaxial side of the leaves and ripe fruits. Note the incurved margins. (C) Epidermal surface of the adaxial side of the leaf in OM. Note the intense sinuosity of anticlinal walls and the cover cells of the secretory cavity (darker color). (D) Surface of the adaxial side of the leaf in SEM. Note the region of the secretory cavity (clustered) and the granules of epicuticular wax (white arrows). (E) Epidermal surface of the abaxial side of the leaf, in OM, showing stomata and trichomes. (F) Epidermal surface of the abaxial side of the leaf in SEM. Note the simple trichomes, stomata (black arrow) and wax in the form of prismatic crystals and grains.
Leaf anatomy
The leaf of M. glomerata is hypostomatic and dorsiventral. The epidermis is uniseriate and presents significant thickening of the cuticle. The mesophyll has oil secretory cavities and calcium oxalate crystals in the form of druses.
In surface view, the adaxial cells of the leaf present markedly sinuous walls (Fig. 1C). The epidermal regions located over the subepidermal secretory cavities can be recognized by the pairs of cover cells or by the single one with spherical contour (Fig. 1C). The adaxial surface observed with SEM reveals granules of epicuticular wax and the aspect of a cover region of a secretory cavity (Fig. 1D). The thickness of the outer walls of the epidermal cells is uneven. Examining the epidermal surface, with OM, this cell characteristic is detected by bright and darker regions that alternate in the periphery of the periclinal walls. In cross section, this irregularity of the thickness is noted by numerous projections of the walls toward the cell (Fig. 2E). This feature also occurs in the cells of the abaxial epidermis, but in an attenuated mode. The abaxial side of the epidermis has simple and long trichomes (Fig. 1E and F) and anomocytic stomata. In SEM it is possible to note the epicuticular wax as grains and rod-shaped and the stomata (Fig. 2A). In CM, the autofluorescence of the adaxial side of the leaf blade becomes visible (Figs. 2D and 3B).