Floral Nectary Anatomy and Ultrastructure in Mycoheterotrophic Plant, Epipogium aphyllum Sw. (Orchidaceae)

Figure 4

Ultrastructure of papillae (TEM). (a) Dense cytoplasm with profuse rough or smooth endoplasmic reticulum, plentiful vesicles (bigger ones with tannin-like materials), numerous mitochondria, and dictyosomes. Notice the vesicles with tannin-like materials in contact with plasmalemma (white arrows) and structurally the same electron-dense bodies (asterisks) in cell wall. The thin layer of swelled cuticle (black arrow). (b) Dense cytoplasm of papillae with spherical mitochondria, plastids with tubular structures, and tannin-like materials. (c) Magnification of (a), vesicle with tannin-like materials in contact with plasmalemma (white arrows), the electron-dense bodies (asterisk) in cell wall, thin layer of cuticle, small vesicles present in cytoplasm and in cell wall. (d) Magnification of (a), the electron-dense body (asterisk) in cell wall. (e, f) In cytoplasm plentiful vesicles are present. (bigger ones with tannin-like materials). Notice the vesicles with tannin-like materials in contact with plasmalemma (white arrows) and structurally the same electron-dense body (black arrow) after building into plasmalemma. The ruptured, thin layer of swelled cuticle caused by pressure of gathered substances. (g) Cell wall structure with visible numerous vesicles and secretion gathered under the cuticle. (h, i) More vacuolated (va: vacuole) cells of outgrowth under the papillae with starchless plastids with tubular structures (c: cuticle, cw: cell wall, d: dictyosomes, ER: profiles of endoplasmic reticulum, m: spherical mitochondria, p: plastids, pl: plasmalemma, se: secretion, t: tannin-like materials, and ve: vesicles).