Cell walls in Cucurbita maxima cotyledons in relation to imbibition

1974 ◽  
Vol 52 (7) ◽  
pp. 1465-1468 ◽  
Author(s):  
John N. A. Lott
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Electron Micrographs ◽  
Propylene Oxide ◽  
Cell Walls ◽  
Scanning Electron Micrographs ◽  
Cucurbita Maxima ◽  
Glutaraldehyde Fixation ◽  
Mesophyll Cells ◽  
Scanning Electron

The scanning electron microscope and the freeze-etch technique were used to demonstrate the presence of corrugated cell walls in cotyledon mesophyll cells from dry squash seeds. These wavy cell walls straightened out during imbibition. In the scanning electron micrographs no wavy cell walls were observed in the smaller epidermal cells. Tissue imbibed for 2 h and then air-dried contained corrugated cell walls, whereas similar imbibed tissue dehydrated in ethanol and propylene oxide contained smooth cell walls. Thus the method of seed dehydration is important in determining the appearance of wavy cell walls. Glutaraldehyde fixation during the 2-h imbibition process did not alter the conditions under which wavy cell walls reappear.

scholarly journals Studies in Oberonia, 9: Lessons from excess names in Oberonia for Orchidaceae systematics, including a revision of the Oberonia Sect. Scytoxiphium

Lankesteriana ◽  
2021 ◽  
Author(s):  
Daniel L. Geiger
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Electron Micrographs ◽  
21St Century ◽  
Expert Advice ◽  
Scanning Electron Micrographs ◽  
Palabras Clave ◽  
Microscope Images ◽  
Typological Thinking ◽  
Scanning Electron

The reasons for excess names in microfloral orchids such as Oberonia Lindl. can be traced to poor scholarship (e.g., failure to review the literature, ignoring expert advice), typological thinking, and erroneous assumption of microendemism. Some extraordinarily poor descriptions, including some from the 21st century, can be termed “taxonomic vandalism”. The outdated reliance on drawings as opposed to z-stacked photographs and scanning electron micrographs poses further problems due to an abundance of demonstrable problems with drawings. The Oberonia sect. Scytoxiphium Schltr. with eight described species is reduced to one species, Oberonia heliophila Rchb.f.; it is illustrated by original drawings, live photographs and scanning electron microscope images. The distribution is extended from Java through Micronesia and Samoa. The species occurs predominantly from 0–500 m, less frequently to 900 m, and possibly to even 1900 m. It flowers throughout the year. Keywords/Palabras clave: Oberonia, Oberonia sect. Scytoxiphium, revision, revisión, synonymies, sinonimias, taxonomic vandalism, vandalismo taxonómico

An SEM study of the cephalic region, buccal cavity and male tail of the species of the genus Strongylus Müller, 1780 (Nematoda, Strongyloidea)

1984 ◽  
Vol 58 (2) ◽  
pp. 149-158 ◽  
Author(s):  
Lynda M. Gibbons
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Electron Micrographs ◽  
Buccal Cavity ◽  
Scanning Electron Micrographs ◽  
Specific Identification ◽  
Male Tail ◽  
Genital Cone ◽  
Sem Study ◽  
Scanning Electron

AbstractThe four species of the genus Strongylus Müller, 1780, namely, S. equinus, S. edentatus, S. vulgaris and S. asini were examined with the scanning electron microscope (SEM). The buccal cavity of each species was cut transversely and longitudinally and the scanning electron micrographs illustrate the shape of the buccal cavity and the dorsal gutter. The micrographs also show the presence of denticles near the oral rim of the buccal cavity of S. edentatus and the shape of the teeth in the buccal cavity of S. equinus, S. vulgaris and S. asini. The bursa of the four species has three symmetrical lobes, one dorsal and two lateral. The length of the three lobes in relation to each other varies between the species. The genital cone has a single large ventral papilla, a pair of dorsal raylets, a median dorsal cuticular appendage and a variety of cuticular appendages lateral and ventral to the cloaca. The development and arrangement of these components differs between the four species of the genus and can be used as a supportive character for specific identification.

scholarly journals Submicroscopical Features of Leaves of Xyris Species

2001 ◽  
Vol 44 (4) ◽  
pp. 405-410 ◽  
Author(s):  
Maria das Graças Sajo ◽  
Silvia Rodrigues Machado
Keyword(s):  
Electron Microscope ◽  
Cell Walls ◽  
Guard Cells ◽  
Leaf Ultrastructure ◽  
Mesophyll Cells ◽  
Transmission Electron ◽  
Inner Surface ◽  
Stomatal Guard Cells ◽  
Adaptative Significance ◽  
Scanning Electron

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.

scholarly journals Morphological and Molecular Characterization of Toxocara apodemi (Nematoda: Ascarididae) from Striped Field Mice, Apodemus agrarius, in Korea

2020 ◽  
Vol 58 (4) ◽  
pp. 403-411
Author(s):  
Hyeon Cheol Kim ◽  
Eui Ju Hong ◽  
Si Yun Ryu ◽  
Jinho Park ◽  
Jeong Gon Cho ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
18S Rrna ◽  
Rrna Gene ◽  
Scanning Electron Micrographs ◽  
Toxocara Cati ◽  
Apodemus Agrarius ◽  
Toxocara Vitulorum ◽  
Field Mice ◽  
Scanning Electron

Adult ascarid worms from the field mice, Apodemus agrarius, were observed with a light and scanning electron microscope, and molecularly analized with 18S rRNA gene. In the scanning electron microscope, 3 prominent labia were present in the anterior end of male and female worms, but the interlabia and gubernaculum were absent. Scanning electron micrographs showed cervical alae as vestigial organs that looked like a slightly uplifted superficial sewing stitch. Total 6 pairs of post-cloacal papillae were observed on the tail of the male worms. The tail of female worms was blunt and conical shape with a spine-like structure, mucron. The eggs were sub-globular, coated with the albuminous layer and 73 by 82 μm in average size. The superficial pits of T. apodemi egg (mean 8.6×6.7 μm) are obviously bigger than those of Toxocara spp. The partial sequence of 18S rRNA showed the sequence homology of Toxocara canis (99.6%), Toxocara cati (99.4%), Toxascaris leonina (99.4%), and Toxocara vitulorum (99.2%). Conclusively, it was confirmed that ascarid nematodes, Toxocara apodemi, recovered from striped field mice in Korea are taxonomically conspecific relationship with genus Toxocara and genetic divergence from other Toxocara species.

Studies in the southern African species of Justicia and Siphonoglossa (Acanthaceae): indumentum

Bothalia ◽  
1990 ◽  
Vol 20 (1) ◽  
pp. 61-66 ◽  
Author(s):  
K. Immelman
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Southern Africa ◽  
Cell Walls ◽  
African Region ◽  
African Species ◽  
Flora Of Southern Africa ◽  
Southern African Region ◽  
Trichome Types ◽  
Scanning Electron

The trichome types present on all species of Justicia and  Siphonoglossa in the southern African region (as defined by the Flora of southern Africa) were examined with the dissecting and with the Scanning Electron Microscope. Both glandular and eglandular trichomes were observed, the former comprising both sessile, peltate glands and stalked glands of various lengths. Eglandular trichomes are either straight or sharply bent (anvil-shaped), and comprise two to many cells. They are either smooth or have raised ornamentation on the cell walls. The presence and morphology of the trichomes on various organs is recorded and measured, and the range of trichomes seen was illustrated. The possible significance of trichome type and ornamentation in the taxonomy and ecology of the genera is discussed.

The microstructure of the dentition and dermal ornament of three dipnoans from the Devonian of Western Australia: a contribution towards dipnoan interrelations, and morphogenesis, growth and adaption of the skeletal tissues

1977 ◽  
Vol 281 (979) ◽  
pp. 29-72 ◽  
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Anterior Part ◽  
Polarized Light ◽  
Scanning Electron Micrographs ◽  
Dental Tissues ◽  
Functional Surfaces ◽  
Current Usage ◽  
First Time ◽  
Scanning Electron

Detailed descriptions of the microstructure, which includes both histology and ultrastructure, are given for each type of tissue in each of the three species of Australian dipnoan. Most of the tissues have not previously been recorded in this way even for other species within the same genera. The microstructure is interpreted from examination of ground sections in transmitted and polarized light, together with examination of functional, forming and fracture surfaces in the scanning electron microscope. No previous studies of dipnoan dental tissues have been published in which the histology is related to surface morphology as seen in the scanning electron microscope. The histology, microstructure, growth and distribution of buccal denticles are described in Griphognathus whitei and Holodipterus gogoensis , and their morphogenesis and adaptation to function is discussed. It is concluded that the phyletic trend towards macromerism, as shown in chondricthyans and primitive teleostomes, is illustrated in the three species of dipnoan. The continuous layer of dentine of the tooth ridges, lips and covering to the dermal snout is described and found to be similar in the three species and equivalent to the tissue described previously in other dipnoans, sometimes as a form of cosmine. A term not in current usage is suggested for this dentine, namely syndentine. Dentine terminology is reviewed and the relevance to dipnoan dental tissues is discussed with the conclusion that an older term should be reintroduced to eliminate the current anomalies in terminology. Chirodipterus australis is the only species with typical tooth plates. The histology is compared with previous accounts of tooth plates in dipnoans and found to have some similarity with those of Neoceratodus forsteri . The microstructure is reported from examination of the worn functional surfaces and acid-etched functional surfaces with the scanning electron microscope, this information has not previously been reported for dipnoan tooth plates and is presented here as a basis for comparison with other species. New features of cosmine structure are described from scanning electron micrographs of the surfaces and these are related to the probable mode of formation and the involvement of the epithelial cells. The structure is found to compare in some ways with the cosmine of osteolepids. The loss of cosmine and replacement by tubercles in Griphognathus whitei and Holodipterus gogoensis is explained as retention of an ontogenetic potential which is comparable with Ørvig’s theory of cosmine regression in the porolepids. Superpositional growth in the dermal skull bones is described for the first time in dipnoans. It is postulated that the ancestors of dipnoans had superimposed denticles beneath a cosmine covering. The information obtained from the microstructure is used to examine the hypothesis proposed by Miles (1977) in a paper on the phyletic relations within the dipnoans. This confirms that Griphognathus white i has retained a primitive dentition with separate buccal denticles and tooth ridges; Holodipterus gogoensis has retained these features, denticles and lip ridges, together with an advanced feature of tooth cusps which are a divergent specialization phyletically preceding tooth plates; Chirodipterus australis has not retained buccal denticles but has lip ridges on the snout and anterior part of the lower jaw, and the specialized tooth plates. Pleromic dentine is recorded in two of these species and discussed with other observed methods of adaptation to wear.

A scanning electron microscope study of Cucurbita maxima seed coat structure

1973 ◽  
Vol 51 (10) ◽  
pp. 1711-1714 ◽  
Author(s):  
John N. A. Lott
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Seed Coat ◽  
Three Dimensional ◽  
Deposition Process ◽  
Dimensional Structure ◽  
Cucurbita Maxima ◽  
Spongy Parenchyma ◽  
Scanning Electron Microscope Study ◽  
Scanning Electron

The examination of the seed coat of Cucurbita maxima with the scanning electron microscope provided information about the three-dimensional structure of the seed coat cells. The lumpy appearance of the spongy parenchyma cells indicated that localized wall growth must have occurred. Also of particular interest were the reticulate secondary wall thickenings in the hypodermal and spongy parenchyma regions of the seed coat. The developing squash seed coat may prove to be a good model system in which to study the cell wall deposition process.

Elemental storage in Cucurbita embryos: X-ray microanalysis of magnesium, potassium, calcium, and phosphorus within globoid crystals

1990 ◽  
Vol 68 (3) ◽  
pp. 646-650 ◽  
Author(s):  
I. Ockenden ◽  
J. N. A. Lott
Keyword(s):  
Neutron Activation Analysis ◽  
Electron Microscope ◽  
Activation Analysis ◽  
Cucurbita Maxima ◽  
Mesophyll Cells ◽  
X Ray ◽  
Reciprocal Hybrids ◽  
Calcium And Phosphorus ◽  
Total Concentrations ◽  
Scanning Electron

Embryos of Cucurbita maxima, Cucurbita andreana, and their reciprocal hybrids store phosphorus, magnesium, potassium, and calcium in distinctive globoid crystals within protein bodies found in cotyledon mesophyll cells. Samples of cotyledon tissue from each of the four kinds of embryos were cryogenically prepared and analyzed by X-ray microanalysis in the frozen state in a scanning electron microscope. The relative proportions of phosphorus, magnesium, potassium, and calcium were expressed as peak to background ratios. Total concentrations of the four elements in whole cotyledons, as measured by neutron activation analysis, were similar to the trends shown by the peak to background ratios for the same elements. This supports the concept that the bulk of the elements P, K, Mg, and Ca in seed tissues is stored in globoid crystals.

Ultrastructure and cytology of pycnia, aecia, and aeciospores of Gymnosporangium clavipes

1975 ◽  
Vol 53 (10) ◽  
pp. 972-977 ◽  
Author(s):  
Frank Kozar ◽  
Hans J. Netolitzky
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Light Microscopy ◽  
Electron Micrographs ◽  
Transmission Electron Micrographs ◽  
Dense Cytoplasm ◽  
Transmission Electron ◽  
Inner Surface ◽  
Scanning Electron

Aeciospores of Gymnosporangium clavipes Cooke & Peck have a surface characterized by a dense covering of baculate projections. Transmission electron micrographs (TEM) reveal a thick non-striated cell wall and a dense cytoplasm. Peridial cells have an inner surface studded with clavate projections. Scanning electron microscope (SEM) microgaphs confirmed earlier light microscopy studies of the existence of fiexious hyphae.

Vessel-Parenchyma Pit Membranes in Cucurbita Maxima Duch.

IAWA Journal ◽  
1986 ◽  
Vol 7 (3) ◽  
pp. 251-254
Author(s):  
María Agueda Castro
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Protective Layer ◽  
Main Character ◽  
Cucurbita Maxima ◽  
Scanning Electron

The structure of the vessel-parenchyma pit membranes of Cucurbita maxima Duch. (Lauraceae) was studied with the scanning electron microscope. The main character of these membranes is the presence of numerous pectocellulosic and non-lignified excrescences, which are considered as part of the protective layer.

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