scholarly journals The morphology and ultrastructure of the nectaries of marrow (Cucurbita pepo L. convar. giromontiina)

2013 ◽  
Vol 66 (3) ◽  
pp. 11-22 ◽  
Author(s):  
Marta Dmitruk ◽  
Elżbieta Weryszko-Chmielewska
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cucurbita Pepo ◽  
Female Flower ◽  
Transmission Electron ◽  
Parenchyma Cells ◽  
Male Flowers ◽  
Nectariferous Tissue ◽  
Female Flowers ◽  
Size And Structure

The present study investigated the size and structure of the nectaries in flowers of marrow – <em>Cucurbita pepo </em>convar.<em> giromontiina </em>cv. ‘Weiser Busch’. The diameter and thickness of nectariferous layer were compared in female and male flowers of this taxon. The micromorphology as well as the anatomical and ultrastructural characters of the nectary from the female flower were observed using light, scanning and transmission electron microscopy. The density and size of stomata of the nectary epidermis from both types of flowers were examined using light microscopy. The nectaries in female flowers were found to have a larger size than in male flowers. The stomata occurring in the nectary epidermis of both types of flowers have a similar size and density. We observed that nectar was released onto the surface of the nectary not only via the stomata, but also through the walls of the epidermal cells. In TEM examination, large nuclei, different-shaped plastids, ER tubules, dictyosomes, and ribosomes were observed in the nectariferous tissue cells. A large number of mitochondria accompanying the plastids were found in the parenchyma cells of the nectary. The degradation of the nectary parenchyma cells in the flowers living for about 6 hours was asynchronous.

scholarly journals Pollination and Fruit Set of Pumpkins in Growers' Fields in New York's Capital District

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 462D-462
Author(s):  
H. Chris Wien ◽  
Dale Riggs
Keyword(s):  
Apis Mellifera ◽  
Cucurbita Pepo ◽  
Fruit Set ◽  
Rating Scale ◽  
Female Flower ◽  
Stigmatic Surface ◽  
Black Light ◽  
Pollen Removal ◽  
Male Flowers ◽  
Female Flowers

Reports of sharply reduced feral bee populations (Apis mellifera) due to harsh winters and prevalence of several bee diseases have raised concerns that pollination and fruit set in pumpkin fields will be adversely affected. In 1995 and 1996, five and eight pumpkin (Cucurbita pepo) fields, respectively, were inventoried on three occasions per season for pollinator activity and percent fruit set. Pollen removal from male flowers was determined visually using a rating scale, while deposition of pollen on stigmata of female flowers was judged by rating fluorescence of pollen on the stigmatic surface under a “black light.” Samples were taken from 15 to 30 locations in each field, and female flowers tagged. These were considered set if they had enlarged to fist size within 14 days. In both years, the amount of pollen remaining on male flowers was negatively correlated with female flower fluorescence ratings. Neither pollen on male flowers nor stigma fluorescence were significantly correlated with percent fruit set. Fifty-two percent of tagged flowers set fruit in both years, with a range of 24% to 84%, and 17% to 78% in 1995 and 1996, respectively. Presence of bee hives in or near the fields had no effect on fruit set. The results indicate that the pollen removal and deposition ratings used were not reliable for predicting fruit set in farmers' fields. In these 2 years, bee hives were not needed in the sampled fields.

Tem Study of Wound-Induced Vessel Occlusions in European Ash (Fraxinus Excelsior L.)

IAWA Journal ◽  
1997 ◽  
Vol 18 (4) ◽  
pp. 401-404 ◽  
Author(s):  
Uwe Schmitt ◽  
Hans Georg Richter ◽  
Claudia Muche
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Outer Membrane ◽  
Fraxinus Excelsior ◽  
Axial Parenchyma ◽  
Transmission Electron ◽  
Parenchyma Cells ◽  
Means Of Transmission ◽  
European Ash

Vessel occlusions in branches of Fraxinus excelsior L. were investigated by means of transmission electron microscopy. The vessel occlusions are formed by exudates released from adjacent ray and axial parenchyma cells through the intact pit membranes. Initial stages mostly display balloon- like structures protruding from the pit aperture into the vessellumen. These inclusions possess a very electron dense outer membrane and dispersed exudates in their interior. Therefore, the vessel occlusions in F. excelsior do not represent true tyloses.

Phosphore, calcium, silicium et fer dans des cristaux, extraits de graines sèches de Raphanus

1984 ◽  
Vol 62 (11) ◽  
pp. 2394-2402 ◽  
Author(s):  
Louis Genevès ◽  
Jacques Rutin ◽  
Sylvain Halpern
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
Electron Probe ◽  
Average Diameter ◽  
Transmission Electron ◽  
Polymorphic Crystals ◽  
Parenchyma Cells ◽  
Ultrathin Sections ◽  
Wavelength Dispersive Spectrometer

Samples were taken from dry seeds of radish and fixed in glutaraldehyde. Ultrathin sections were observed without contrasting treatment. From cotyledonary parenchyma, it was possible to obtain powders or prints, which were observed by transmission electron microscopy. They showed several types of crystals. In the ultrathin sections of parenchyma cells, the crystals are included in globoids. Electron probe microanalysis with a wavelength dispersive spectrometer (Camebax microprobe) showed that they were rich in P, Ca, and Mg. In the powders and the prints, several polymorphic crystals, of varied sizes, were observed; these were sensitive to the electron beam. Some have relatively high ratios in Ca, lower ratios of S, and other elements, such as Si. Others possessed high ratios of Si with other elements, such as Ca and Al. The latter were less dense, more stable under the beam and their average diameter was smaller. Other crystals were smaller (some tenths of a micrometre). They were electron dense and very stable. Some of these were rich in Fe and could contain other elements (among others Si, Ca and P).

scholarly journals Ultrastructural Studies of `Kensington' Mango (Mangifera indica Linn.) Heat Injuries

HortScience ◽  
1995 ◽  
Vol 30 (1) ◽  
pp. 102-103 ◽  
Author(s):  
Keryl K. Jacobi ◽  
Don Gowanlock
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Walls ◽  
Mangifera Indica ◽  
Hot Water ◽  
Hot Water Treatment ◽  
Mango Fruit ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Parenchyma Cells

Mature green `Kensington' mango fruit were submerged in hot water at 46C until the fruit center reached 45C and then held for 30 minutes. The fruit were allowed to ripen for 7 to 10 days after the hot water treatment, and then damaged areas of skin and mesocarp tissue were prepared for observation by scanning and transmission electron microscopy. Heating-related injuries included rupturing the patterned cuticle and exocarp and exposing the underlying cells and hollow cavities (which varied in size and shape) randomly distributed within the mesocarp beneath the skin. Starch deposits still were present in the mesocarp parenchyma cells. The cell walls of damaged mesocarp parenchyma cells were convoluted and thickened in places. The injury suggested disruption of enzymes involved in carbohydrate metabolism.

Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

1971 ◽  
Vol 29 ◽  
pp. 204-205
Author(s):  
G. G. Shaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Pure Aluminum ◽  
Ion Milling ◽  
Transmission Electron ◽  
Fiber Matrix ◽  
Ion Erosion ◽  
Row Of Fibers

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

Two- or three-way observations of the identical cell elements within the same sections by LM, TEM and/or SEM

1978 ◽  
Vol 36 (2) ◽  
pp. 82-83 ◽  
Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Thin Sections ◽  
Transmission Electron ◽  
Identical Cell ◽  
Electron Microscopes ◽  
Scanning Electron

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).

Comparative Microstructures of Ion Milled and Electrochemically Thinned Composite Materials

1974 ◽  
Vol 32 ◽  
pp. 546-547
Author(s):  
R.R. Russell
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Composite Materials ◽  
Great Difficulty ◽  
Ion Milling ◽  
Transmission Electron ◽  
Ion Damage ◽  
Intermetallic Composite

Transmission electron microscopy of metallic/intermetallic composite materials is most challenging since the microscopist typically has great difficulty preparing specimens with uniform electron thin areas in adjacent phases. The application of ion milling for thinning foils from such materials has been quite effective. Although composite specimens prepared by ion milling have yielded much microstructural information, this technique has some inherent drawbacks such as the possible generation of ion damage near sample surfaces.

Maytansine-Induced Mitotic Arrest in Human Lymphoblasts

1977 ◽  
Vol 35 ◽  
pp. 460-461
Author(s):  
Tai-Te Chao ◽  
John Sullivan ◽  
Awtar Krishan
Keyword(s):  
Electron Microscopy ◽  
Cell Cycle ◽  
Transmission Electron Microscopy ◽  
Tubulin Polymerization ◽  
Vinca Alkaloids ◽  
Antimitotic Activity ◽  
Transmission Electron ◽  
Flow Microfluorometry ◽  
Brain Tubulin

Maytansine, a novel ansa macrolide (1), has potent anti-tumor and antimitotic activity (2, 3). It blocks cell cycle traverse in mitosis with resultant accumulation of metaphase cells (4). Inhibition of brain tubulin polymerization in vitro by maytansine has also been reported (3). The C-mitotic effect of this drug is similar to that of the well known Vinca- alkaloids, vinblastine and vincristine. This study was carried out to examine the effects of maytansine on the cell cycle traverse and the fine struc- I ture of human lymphoblasts.Log-phase cultures of CCRF-CEM human lymphoblasts were exposed to maytansine concentrations from 10-6 M to 10-10 M for 18 hrs. Aliquots of cells were removed for cell cycle analysis by flow microfluorometry (FMF) (5) and also processed for transmission electron microscopy (TEM). FMF analysis of cells treated with 10-8 M maytansine showed a reduction in the number of G1 cells and a corresponding build-up of cells with G2/M DNA content.

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