scholarly journals Micromorphology of Sorbus intermedia Pers. nectary surface in different phases of blooming

2012 ◽  
Vol 59 (1) ◽  
pp. 49-59
Author(s):  
Elżbieta Weryszko-Chmielewska ◽  
Agata Konarska

The structure of floral nectary surface of <i>Sorbus intermedia</i> in different phases of flower development was examined using scanning electron microscopy. Nectaries in <i>S. intermedia</i> flowers represent a receptacle type. The sculpture of cuticule on nectary epidermis and overlaying cells was described. The differences in the size of striaes on the outer cell wall of epidermis during the flower development were stated. Nectarostomata were situated in small hollows. In the buds, they were closed and not fully developed. During pollen release phase, the outer ledges of the guard cells were better developed than at the beginning of blooming. Depressions on nectary epidermis cell walls were observed in the final phase of blooming.

2012 ◽  
Vol 60 (1) ◽  
pp. 35-43
Author(s):  
Agata Konarska

The study of floral nectary structures of thirteen ornamental apple cultivars examined using light microscope (MS) and scanning electron microscope (SEM) was performed. It was found that nectary glands in the selected cultivars were located in the upper part of the flower receptacle, between the ovary of the pistil and the base of stamen filaments, and they generally belonged to the epimorphic or transitoric type. The nectary surface area, its thickness, the number of glandular tissue layers, the height of epidermal cells of the nectary and the thickness of the outer wall of the epidermis, together with the cuticle, were determined by light microscope. By using SEM, the structure of the surface of nectaries in four ornamental apple cultivars was observed. The epidermis of the upper part of the nectaries was composed of elongated cells of which outer cell wall was covered with a striated cuticle. The remaining part of the nectary was characterised by cells of similar arrangement and shape, but their surface was marked by a thinner and smoother layer of cuticle. Closed or opened stomata were generally situated at the level of the epidermal cells. Their pores were often filled with granular or plate-shaped structures.


1974 ◽  
Vol 52 (9) ◽  
pp. 2033-2036 ◽  
Author(s):  
N. C. Lyon ◽  
W. C. Mueller

Leaf tissue of Phaseolus vulgaris L. and Plantago major L. was prepared by the freeze-etch technique and examined in the electron microscope for the presence of ectodesmata. No structures analagous to ectodesmata observed with light microscopy could be found in freeze-etched preparations of chemically unfixed material or in material fixed only in glutaraldehyde. Objects appearing as broad, shallow, granular areas in the epidermal cell wall beneath the cuticle were observed in leaf replicas after fixation in complete sublimate fixative, the acid components of the sublimate fixative, or mercuric chloride alone. Because of their distribution and location, these objects can be considered analagous to ectodesmata observed by light microscopists. Because these areas occur only in chemically fixed walls and are localized within the walls in discrete areas, their presence supports the contention that ectodesmata are sites in the outer cell wall with defined physicochemical characteristics.


2001 ◽  
Vol 44 (4) ◽  
pp. 405-410 ◽  
Author(s):  
Maria das Graças Sajo ◽  
Silvia Rodrigues Machado

The leaf ultrastructure of five Xyris species were examined using scanning electron microscope (SEM), transmission electron microscope (TEM) and histochemical methods. All studied leaves show some features in epidermis and mesophyll, which were of considerable adaptative significance to drought stress. Such features included the occurrence of a pectic layer on the stomatal guard cells and the presence of a network of pectic compounds in the cuticle. Pectic compunds were also in abundance in lamellated walls of the mesophyll cells and on the inner surface of the sclerified cell walls of the vascular bundle sheaths. There were also specialized chlorenchymatous "peg cells" in the mesophyll and drops of phenolic compounds inside the epidermal cells.


Botany ◽  
2019 ◽  
Vol 97 (1) ◽  
pp. 1-21
Author(s):  
Jay F. Anderson ◽  
Hema S.N. Duddu ◽  
Steven J. Shirtliffe ◽  
Arthur R. Davis

Silene latifolia Poiret of Eurasia has established in North America, prompting this structural study of its mature unisexual buds and flowers. Floral nectaries, anther and stigma changes, and vestigial reproductive structures were studied using light and scanning electron microscopy. In staminate flowers, anthers dehisced before anthesis and >90% of their pollen was liberated within 36 h. Accumulated in the tubular calyx, nectar descended an anthophore from the stomatal-bearing nectary at the stamen bases. Nectary tissue surrounded the pistillode, a central filamentous organ lacking ovules but tipped by hairs resembling stigmatic papillae. In pistillate flowers, nectar flowed into an inflated calyx. The annular nectary had 10 regularly spaced, stomatal-lined craters and was continuous with the adaxial surfaces of the infertile antisepalous and epipetalous staminodes. Key elements of entomophilous pollination leading to successful sexual reproduction of this invasive species include secondary nectar presentation from disparate floral nectaries that, for pistillate flowers, also incorporate the staminodes; rapid pollen release from anthers; and elongation of papillae by tip growth that enhances each stigma’s receptive surface. Context is also provided for future studies of floral nectary development in this model dioecious species.


2000 ◽  
Vol 78 (6) ◽  
pp. 824-831 ◽  
Author(s):  
Audrey Chapman ◽  
Anne-Sophie Blervacq ◽  
Théo Hendriks ◽  
Christian Slomianny ◽  
Jacques Vasseur ◽  
...  

In Cichorium hybrid clone 474 (C. intybus L. var. sativum × C. endivia L. var. latifolia), direct somatic embryogenesis was induced from roots. Using transmission electron microscopy, we followed the ultrastructural changes of the outer cell wall in relation to embryo developmental stage. During the transition from an embryogenic cell to a somatic embryo, the differentiation of the outer cell wall involved both deposition and rearrangement processes. During the first divisions, the cell wall of few-celled embryos still enclosed in the root tissue appeared as a large amorphous layer of cellulose, thicker than the cell walls of the root cortex cells. When the proembryo emerged from the root cells, the outer wall surface exhibited a fibrillar material designated as the supraembryonic network. As this network disappeared, the outer cell wall changed organization, and two domains were distinguished. At the torpedo stage, the outer cell wall was more compact without any gaps and the protoderm was differentiated. Immunolocalization of an epitope recognised by JIM5 antibody revealed the unesterified nature of the supraembryonic network. Such pectins were also located at the outer third of the outer cell wall of protodermal cells as well as in the intercellular spaces. Highly methylesterified pectins recognized by JIM7 antibodies were slightly present in the cell walls during the embryogenesis process. The different stages of the outer cell wall differentiation as well as the development of the transient supraembryonic network are described, and its possible roles in somatic embryogenesis are proposed.Key words: cell differentiation, cell wall, Cichorium (chicory), pectin, somatic embryogenesis, transmission electron microscopy.


Phytotaxa ◽  
2014 ◽  
Vol 167 (1) ◽  
pp. 79 ◽  
Author(s):  
JONATHAN C. TAYLOR ◽  
BALASUBRAMANIAN KARTHICK ◽  
CHRISTINE COCQUYT ◽  
PAULINE LANG

Diploneis fenestrata, a new aerophilic diatom is described from Lumangwe falls, Zambia. This novel species occurs as an epiphyte on the roots and stems of trees located within the spray zone of the falls. Its morphology was examined with both light and scanning electron microscopy. Diploneis fenestrata is distinguished from other taxa in the genus Diploneis by its prominent square openings ranging in number from 4-14 occurring within the area of the longitudinal canal only at the outer cell wall. The occurrence of these characteristic square openings found in the genus Diploneis is further discussed.


Weed Science ◽  
1992 ◽  
Vol 40 (2) ◽  
pp. 288-295 ◽  
Author(s):  
Gary F. Joye ◽  
Rex N. Paul

Infection of Hydrilla verticillata by Macrophomina phaseolina was investigated using scanning and transmission electron microscopy. Sprigs of plants in petri plates were inoculated with suspensions of fungal hyphae. Samples of inoculated and noninoculated plants were taken over time. Fungal cells attached to lower epidermal cell walls but not the upper epidermal cell walls of leaves. In less than 40 h, penetration through the cell wall was completed and colonization of host cells was observed. Penetration of upper epidermis was limited to the cell wall adjacent to a lower epidermal cell. No penetration was observed through the outer cell wall of upper epidermis. Inhibition of penetration through the outer cell wall of the upper epidermis may be attributable to an osmiophilic layer below the cell wall. Disruption of the host cell walls and subsequent host cell death was preceded by massive colonization of the host by this pathogen.


Author(s):  
P. Dayanandan ◽  
P. B. Kaufman

A three dimensional appreciation of the guard cell morphology coupled with ultrastjuctural studies should lead to a better understanding of their still obscure dynamics of movement. We have found the SEM of great value not only in studies of the surface details of stomata but also in resolving the structures and relationships that exist between the guard and subsidiary cells. We now report the isolation and SEM studies of guard cells from nine genera of plants.Guard cells were isolated from the following plants: Psilotum nudum, four species of Equisetum, Cycas revoluta, Ceratozamia sp., Pinus sylvestris, Ephedra cochuma, Welwitschia mirabilis, Euphorbia tirucalli and Allium cepa.


Author(s):  
T.A. Fassel ◽  
M.J. Schaller ◽  
C.C. Remsen

Methane, a contributor to the “greenhouse effect”, is oxidized in the natural environment by methanotrophic bacteria. As part of a comprehensive research effort, we have been examining the ultrastructure of methanotrophs. These microorganisms have complex outer cell wall structures similar to those frequently found in other chemol itho- trophic bacteria. (1,2)In our work, we have focused on the “type” strains of Methylomonas albus BG8 and Methylosinus trichosporium OB3b. Between Spurr and LR White embedding resins, we found a difference 1n the preservation of an outer cup layer of BG8 external to the peripheral membranes. Cells from the same sample embedded in Spurr consistently lacked this feature (FIG. 1). This effect was overcome by an en bloc ruthenium red (RR) protocol that resulted in successful retention of the cup layer in Spurr resin (FIG. 2). For OB3b cells, the en bloc RR protocol resulted in an exterior bead feature distinguishable in thin section (FIG. 4) that previously was seen only by SEM.


2017 ◽  
Vol 51 ◽  
pp. 274-280
Author(s):  
A. D. Potemkin ◽  
Yu. S. Mamontov ◽  
N. S. Gamova

Study of selected specimens of Gymnomitrion collected by D. G. Long in Yunnan, China, revealed a new species, G. fissum Mamontov et Potemkin, sp. nov., with a fissured leaf surface. Comparison of SEM images of the leaf surface and leaf cross sections shows that the leaf surface of G. fissum is different from that of other known species with a superficially similar leaf surface, i. e. Mylia taylorii, M. verrucosa s. l. and Trabacellula tumidula. It has fissures around the cell lumen rather than grids and perforations. Outer cell walls of Gymnomitrion fissum are much thicker than in Mylia taylorii, M. verrucosa s. l. and Trabacellula tumidula, and their outer layers tend to be partly or completely caducous. G. fissum is related to the group of species assigned to the former genus Apomarsupella.


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