Figure 1
Inflorescence of Vigna luteola. a, in vivo, on 14 February 2011; b and c, schematic representation of an inflorescence (white semi-circles, flowers; black circles, extrafloral nectaries: b, vertical diagram, c, transverse diagram showing structures at a secondary axis; d, SEM of a secondary axis with 3 linearly arranged extrafloral nectaries (S0, S3, S2) at different stages and lateral flowers (f) removed. Scale bars = b: 15 cm; c: 3 cm; d: 500 μm.
Figure 2
LM micrographs of longitudinal sections of ontogenetic stages of extrafloral nectary of V. luteola. a, stage 1: flower bud and bracteoles, surrounded by developing ring; b, c, stage 2: b, ring completely developed, bract covering bracteoles and flower bud, flower bud with sepal primordia; c, ring, bract protecting bracteoles and flower bud under which abscission zone is visible (below this, central cells irrigated by vascular bundles); d, e, stage 3: d, central cells with dense content, in contrast to highly vacuolated cells of ring; e, detail of vascular supply and central cells; f, stage 4: general appearance of degenerated extrafloral nectary with center narrowed. Abbreviations: α, β, bracteoles; a, abscission zone; b, bract; cc, central cells; f, flower bud; r, ring; se, sepal; v, vascular bundles. Scale bars = b, d, f: 10 μm; a, e: 4 μm.
Figure 3
SEM micrographs of secretory and postsecretory stages of extrafloral nectary of V. luteola. a, c, stage 3 (secretory); d, stage 4 (postsecretory); a, central cells surrounded by a completely developed ring; b, elongated papillose central cells; c, detail of papillose central cells; d, desintegration of papillose central cells while the ring remains. Abbreviations: cc, central cells; r, ring. Scale bars = a: 200 μm; b: 50 μm; c, d: 10 μm.
Figure 4
TEM micrographs of ring cells at secretory stage of an extrafloral nectary of V. luteola. a. Detail of an epidermal cell with rough endoplasmic reticulum and vacuole, electron-dense corpuscles (arrows) between plasma membrane and external tangential wall, as well as on wall, where also secretion is observed (arrow heads); b, detail of an epidermal cell (right) and two underlying parenchyma cells (left): lipid globules, mitochondria, rough endoplasmic reticulum, vacuoles and secretion from underlying parenchyma (arrows heads); c, detail of underlying parenchyma cells with free ribosomes, mitochondria, rough endoplasmic reticulum and vacuole; d, plasmodesmata (arrows) connecting parenchyma cells, which exhibit chloroplast, dictyosomes, mitochondria and vacuoles. Note vesicle in exocytosis close to fibrillar and electron-dense content of vacuole (right, bottom). Abbreviations: cl, chloroplast; d, dictyosome; l, lipid globule; m, mitochondria; rER, rough endoplasmic reticulum; va, vacuole; ve, vesicle. Scale bars = a, b: 0.5 μm; c: 0.2 μm; d: 1 μm.
Figure 5
TEM micrographs of central cells at secretory stage of an extrafloral nectary of V. luteola. a, longitudinal section of apical portion of an elongated central cell showing amyloplasts, lipid globules and secretion outside wall (arrow heads); b, detail of wall of a papillose cell with electron-dense cuticle; c, detail of a papillose cell with vacuole, rER, dictyosome and lipid globule; d, underlying parenchyma cells with big nucleous, rough endoplasmic reticulum, plastid, mitochondria, dictyosomes, small vacuoles, invaginations along plasmalemma (white arrows), electron-dense corpuscules associated with plasmalemma (arrow heads) and plasmodesmata (black arrows). Abbreviations: a, amyloplast; cu, cuticle; d, dictyosome; l, lipidic globule; m, mitochondria; n, nucleous; p, plastid; rER, rough endoplasmic reticulum; va, vacuole. Scale bars = a, d: 1 μm; b, c: 0.1 μm.
Development and differentiation of the extrafloral nectaries from flower buds in Vigna luteola (Leguminosae, Phaseolinae)
Thumbnail
Thumbnail
Thumbnail
Thumbnail
Thumbnail
