scholarly journals Nectary structure of Ornithidium sophronitis Rchb.F. (Orchidaceae: Maxillariinae)

2012 ◽  
Vol 62 (2) ◽  
pp. 3-12 ◽  
Author(s):  
Małgorzata Stpiczyńska ◽  
Kevin L. Davis ◽  
Alan Gregg
Keyword(s):  
Food Reward ◽  
Ventral Surface ◽  
Secretory Cells ◽  
Nectary Structure ◽  
Floral Characters

Most orchids do not produce floral food-rewards. Instead, they attract pollinators by mimicry or deceit. When present, the most common floral food-reward is nectar. To date, nectary structure has been described for only two species of <i>Maxillaria sensu lato</i>, namely <i>Maxillariella anceps</i> and <i>Ornithidium coccineum</i> (formerly <i>Maxillaria anceps</i> and <i>M. coccinea</i>, respectively). Here, we describe that of a third species, <i>Ornithidium sophronitis</i> (formerly <i>Maxillaria sophronitis</i>). This species possesses floral characters concomitant with ornithophily. A 'faucet and sink' arrangement is present, with nectar secreted by a protuberance on the ventral surface of the column, collecting between column and tepal bases. The nectary of <i>O. sophronitis</i> shares many features with that of <i>O. coccineum</i>. It has a single-layered epidermis and 3- 5 layers of small, subepidermal, collenchymatous, secretory cells. Beneath these occur 2-3 layers of larger, subsecretory, parenchymatous cells supplied by phloem. Nectary cell vacuoles contain osmiophilic material and proteinaceous intravacuolar bodies. Moreover, distension of the nectary cuticle occurs as nectar accumulates between it and the secretory epidermis. Subsecretory cells, however, have thinner walls and contain flocculent, intravacuolar precipitates that may be related to the presence of flavonoids. Since the floral and nectary structure of <i>O. sophronitis</i> is very similar to that of closely related <i>Ornithidium coccineum</i>, it may have evolved in like manner in response to similar pollinator pressures.

scholarly journals Evidence for the Dual Role of Floral Secretory Cells in Bulbophyllum

2016 ◽  
Vol 58 (2) ◽  
pp. 57-69 ◽  
Author(s):  
Małgorzata Stpiczyńska ◽  
Kevin L. Davies
Keyword(s):  
Endoplasmic Reticulum ◽  
Food Reward ◽  
Smooth Endoplasmic Reticulum ◽  
Dual Role ◽  
Epidermal Cells ◽  
Secretory Cells ◽  
Oil Droplets ◽  
Cytoplasmic Inclusions ◽  
Rich Food ◽  
Protein Rich

Abstract Floral epidermal cells of most species of Bulbophyllum Thouars studied to date produce both lipid-rich food-rewards and fragrance. Since fragrances largely consist of terpenoids and have an affinity for lipophilic stains, the simultaneous presence of lipid-rich food-rewards frustrates identification of fragrance-secreting cells by conventional histochemistry. Furthermore, since both lipid-rich food-rewards and fragrances are probably synthesized by a similar complement of organelles, interpretation of TEM images can prove difficult. All members of section Racemosae Benth. & Hook. f. investigated to date, however, are unusual in their secretion of a predominantly proteinaceous food-reward, and lipids are seemingly absent. This might enable their use as models for the identification and characterization of fragrance-secreting tissues and organelles. Three members of sect. Racemosae were chosen, namely Bulbophyllum dissitiflorum Seidenf., B. lilacinum Ridl. and B. tricorne Seidenf. & Smitinand. All produced food-rewards. Of these, one (B. dissitiflorum) lacked fragrance and was used as a control, whereas the remaining two species produced fragrance. Having established that the food-reward was mainly proteinaceous in each case, and did not test positively for lipid, we undertook further histochemical investigations, as well as light microscopy, SEM and TEM. Specialized palisade-like epidermal cells of all species contained protein bodies and rough endoplasmic reticulum consistent with the production and secretion of a protein-rich food-reward. Cuticular pores were also present. In fragrant species, these cells also contained abundant smooth endoplasmic reticulum, oil droplets and many, well-developed, spherical plastids with numerous plastoglobuli, similar to those found in the osmophores (fragrance-producing structures) of other orchids. Indeterminate, osmiophilic cytoplasmic inclusions were also present. By contrast, the non-fragrant species lacked oil droplets and other osmiophilic inclusions and the plastids were scant, poorly developed, often elongate or irregular in shape and contained few plastoglobuli. Smooth endoplasmic reticulum was also less frequent. Since food-rewards tested negatively for lipid, it is probable that any oil droplets present were involved in fragrance production, especially since they were absent from the non-fragrant species. Thus, the unusual absence of lipids from the food-rewards of sect. Racemosae provided a rare opportunity, permitting, for the first time, the unraveling of these two secretory processes (food-reward and fragrance) in Bulbophyllum and clearly demonstrating the plasticity of these cells and their dual role in secretion.

scholarly journals Visibility and attractiveness of Fritillaria (Liliaceae) flowers to potential pollinators

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Katarzyna Roguz ◽  
Laurence Hill ◽  
Sebastian Koethe ◽  
Klaus Lunau ◽  
Agata Roguz ◽  
...  
Keyword(s):  
Food Reward ◽  
Potential Role ◽  
Flower Colour ◽  
Floral Traits ◽  
Nectar Guides ◽  
Flower Colours ◽  
Visual Attraction ◽  
Floral Characters ◽  
Plant Pollinator

AbstractVisual floral characters play an important role in shaping plant-pollinator interactions. The genus Fritillaria L. (Liliaceae), comprising approximately 140 species, is described as displaying a remarkable variety of flower colours and sizes. Despite this variation in visual floral traits of fritillaries, little is known about the potential role of these features in shaping plant-pollinator interactions. Here, we seek to clarify the role of visual attraction in species offering a robust food reward for pollinators early in the spring, which is the case for Fritillaria. We also searched for potential tendencies in the evolution of floral traits crucial for plant-pollinator communication. The generality of species with green and purple flowers may indicate an influence of environmental factors other than pollinators. The flowers of the studied species seem to be visible but not very visually attractive to potential pollinators. The food rewards are hidden within the nodding perianth, and both traits are conserved among fritillaries. Additionally, visual floral traits are not good predictors of nectar properties. When in the flowers, pollinators are navigated by nectar guides in the form of contrasting nectary area colouration. Flower colour does not serve as a phenotypic filter against illegitimate pollinators—red and orange bird-pollinated fritillaries are visible to bees.

The ultrastructure of acinar cells in the external orbital gland of young and old male rats

1978 ◽  
Vol 36 (2) ◽  
pp. 276-277
Author(s):  
R. Carriere
Keyword(s):  
Young Adulthood ◽  
Acinar Cells ◽  
Cell Number ◽  
Male Rats ◽  
Polyploid Cell ◽  
Secretory Cells ◽  
Age Changes ◽  
Albino Rat ◽  
Golgi Membranes ◽  
Diploid Cells

The external orbital gland of the albino rat exhibits both sexual dimorphism and histological age changes. In males, many cells attain a remarkable degree of polyploidy and an increase of polyploid cell number constitutes the major age change until young adulthood. The acini of young adults have a small lumen and are composed of tall serous cells. Subsequently, many acini acquire a larger lumen with an irregular outline while numerous vacuoles accumulate throughout the secretory cells. At the same time, vesicular acini with a large lumen surrounded by pale-staining low cuboidal diploid cells begin to appear and their number increases throughout old age. The fine structure of external orbital glands from both sexes has been explored and in considering acinar cells from males, emphasis was given to the form of the Golgi membranes and to nuclear infoldings of cytoplasmic constituents.

New Ultrastructural Observations on Injury and Regeneration of Cilia in Mammalian Conducting Airway Epithelium

1981 ◽  
Vol 39 ◽  
pp. 624-625
Author(s):  
J.L. Carson ◽  
A.M. Collier
Keyword(s):  
Respiratory Tract ◽  
Airway Epithelium ◽  
Defense Mechanisms ◽  
Normal Growth ◽  
Fetal Lung ◽  
Secretory Cells ◽  
Airway Epithelial ◽  
Ciliated Cells ◽  
Conducting Airway ◽  
Conducting Airways

The ciliated cells lining the conducting airways of mammals are integral to the defense mechanisms of the respiratory tract, functioning in coordination with secretory cells in the removal of inhaled and cellular debris. The effects of various infectious and toxic agents on the structure and function of airway epithelial cell cilia have been studied in our laboratory, both of which have been shown to affect ciliary ultrastructure.These observations have led to questions about ciliary regeneration as well as the possible induction of ciliogenesis in response to cellular injury. Classical models of ciliogenesis in the conducting airway epithelium of the mammalian respiratory tract have been based primarily on observations of the developing fetal lung. These observations provide a plausible explanation for the embryological generation of ciliary beds lining the conducting airways but do little to account for subsequent differentiation of ciliated cells and ciliogenesis during normal growth and development.

Analysis of the Anterior Secretory Cells of Onchidohs Muricata (Nudibranchia)

1981 ◽  
Vol 39 ◽  
pp. 614-615
Author(s):  
Roy Skidmore
Keyword(s):  
Endoplasmic Reticulum ◽  
Secretory Granules ◽  
Golgi Body ◽  
The Body ◽  
Secretory Cells ◽  
Secretory Vesicles ◽  
High Magnification ◽  
Large Numbers ◽  
Membrane Bound ◽  
Sole Of The Foot

The long-necked secretory cells in Onchidoris muricata are distributed in the anterior sole of the foot. These cells are interspersed among ciliated columnar and conical cells as well as short-necked secretory gland cells. The long-necked cells contribute a significant amount of mucoid materials to the slime on which the nudibranch travels. The body of these cells is found in the subepidermal tissues. A long process extends across the basal lamina and in between cells of the epidermis to the surface of the foot. The secretory granules travel along the process and their contents are expelled by exocytosis at the foot surface.The contents of the cell body include the nucleus, some endoplasmic reticulum, and an extensive Golgi body with large numbers of secretory vesicles (Fig. 1). The secretory vesicles are membrane bound and contain a fibrillar matrix. At high magnification the similarity of the contents in the Golgi saccules and the secretory vesicles becomes apparent (Fig. 2).

Scanning and Transmission Electron Microscopy of the Endometrium in Women with Ovarian Dysgenesis (Turner'S Syndrome)

1976 ◽  
Vol 34 ◽  
pp. 148-149
Author(s):  
A. González-Angulo ◽  
S. Armendares-Sagrera ◽  
I. Ruíz de Chávez ◽  
H. Marquez-Monter ◽  
R. Aznar
Keyword(s):  
Surface Epithelium ◽  
Secretory Cells ◽  
Turner's Syndrome ◽  
Ciliated Cells ◽  
Turner’S Syndrome ◽  
Exogenous Hormone ◽  
Ovarian Dysgenesis ◽  
Transmission Electron ◽  
Normal Women ◽  
Microscopy Examination

It is a well documented fact that endometrial hyperplasia and adenocarcinoma may develop in women with Turner's syndrome who had received unopposed estrogen treatment (1), as well as in normal women under contraceptive medication with the sequential regime (2). The purpose of the present study was to characterize the possible changes in surface and glandular epithelium in these women who were treated with a sequential regime for a period of between three and eight years. The aim was to find organelle modifications which may lead to the understanding of the biology of an endometrium under exogenous hormone stimulation. Light microscopy examination of endometrial biopsies of nine patients disclosed a proliferative pattern; in two of these, there was focal hyperplasia. With the scanning electron microscope the surface epithelium in all biopsies showed secretory cells with microvilli alternating with non secretory ciliated cells. Regardless of the day of the cycle all biopsies disclosed a large number of secretory cells rich in microvilli (fig.l) with long and slender projections some of which were branching (fig. 2).

Scanning electron microscopy of the integument of schistosoma rodhaini

1986 ◽  
Vol 44 ◽  
pp. 132-133
Author(s):  
P. Evers ◽  
C. Schutte ◽  
C. D. Dettman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Oral Sucker ◽  
Adult Male ◽  
Dorsal Surface ◽  
Ventral Surface ◽  
Sensory Receptors ◽  
East African ◽  
Dorsal Midline ◽  
Scanning Electron

S.rodhaini (Brumpt 1931) is a parasite of East African rodents which may possibly hybridize with the human schistosome S. mansoni. The adult male at maturity measures approximately 3mm long and possesses both oral and ventral suckers and a marked gynaecophoric canal. The oral sucker is surrounded by a ring of sensory receptors with a large number of inwardly-pointing spines set into deep sockets occupying the bulk of the ventral surface of the sucker. Numbers of scattered sensory receptors are found on both dorsal and ventral surfaces of the head (Fig. 1) together with two conspicuous rows of receptors situated symmetrically on each side of the midline. One row extends along the dorsal surface of the head midway between the dorsal midline and the lateral margin.

Ultrastructural studies of the relationship between actin filaments and secretory granules

1990 ◽  
Vol 48 (3) ◽  
pp. 458-459
Author(s):  
Ellen Holm Nielsen
Keyword(s):  
Electron Microscopy ◽  
Colloidal Gold ◽  
Actin Filaments ◽  
Secretory Granules ◽  
Secretory Cells ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Granule Membrane ◽  
Ultrathin Sections ◽  
Lowicryl K4m

In secretory cells a dense and complex network of actin filaments is seen in the subplasmalemmal space attached to the cell membrane. During exocytosis this network is undergoing a rearrangement facilitating access of granules to plasma membrane in order that fusion of the membranes can take place. A filamentous network related to secretory granules has been reported, but its structural organization and composition have not been examined, although this network may be important for exocytosis.Samples of peritoneal mast cells were frozen at -70°C and thawed at 4°C in order to rupture the cells in such a gentle way that the granule membrane is still intact. Unruptured and ruptured cells were fixed in 2% paraformaldehyde and 0.075% glutaraldehyde, dehydrated in ethanol. For TEM (transmission electron microscopy) cells were embedded in Lowicryl K4M at -35°C and for SEM (scanning electron microscopy) they were placed on copper blocks, critical point dried and coated. For immunoelectron microscopy ultrathin sections were incubated with monoclonal anti-actin and colloidal gold labelled IgM. Ruptured cells were also placed on cover glasses, prefixed, and incubated with anti-actin and colloidal gold labelled IgM.

Correlative transmission and high-resolution scanning electron microscopic studies on pituitary cells

1990 ◽  
Vol 48 (3) ◽  
pp. 20-21
Author(s):  
S. Tai
Keyword(s):  
Cell Types ◽  
Depth Of Field ◽  
Secretory Cells ◽  
Specific Cell ◽  
Pituitary Cells ◽  
Electron Microscopic ◽  
3 Dimensional ◽  
Microscopic Studies ◽  
Structure And Activity ◽  
Intracellular Structure

Extensive cytological and histological research, correlated with physiological experimental analysis, have been done on the anterior pituitaries of many different vertebrates which have provided the knowledge to create the concept that specific cell types synthesize, store and release their specific hormones. These hormones are stored in or associated with granules. Nevertheless, there are still many doubts - that need further studies, specially on the ultrastructure and physiology of these endocrine cells during the process of synthesis, transport and secretion, whereas some new methods may provide the information about the intracellular structure and activity in detail.In the present work, ultrastructural study of the hormone-secretory cells of chicken pituitaries have been done by using TEM as well as HR-SEM, to correlate the informations obtained from 2-dimensional TEM micrography with the 3-dimensional SEM topographic images, which have a continous surface with larger depth of field that - offers the adventage to interpretate some intracellular structures which were not possible to see using TEM.

The neuroscience of food reward

2010 ◽  
Author(s):  
L. N. Van der Laan ◽  
P. A. M. Smeets ◽  
M. A. Viergever ◽  
D. T. D. De Ridder
Keyword(s):  
Food Reward
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