Cytology of mucilage production in the seed coat of Candle canola (Brassica campestris)

1981 ◽  
Vol 59 (3) ◽  
pp. 292-300 ◽  
Author(s):  
L. Van Caeseele ◽  
J. T. Mills ◽  
M. Sumner ◽  
R. Gillespie
Keyword(s):  
Electron Microscopy ◽  
Seed Coat ◽  
Brassica Campestris ◽  
Light And Electron Microscopy ◽  
Epidermal Cells ◽  
Starch Grains ◽  
Golgi Bodies ◽  
Tangential Wall ◽  
Membrane Bound

The development of mucilage in the epidermal cells of canola seeds (Brassica campestris L. cv. Candle) was studied with light and electron microscopy from 5 days after pollination to maturity. During the first 17 days starch was deposited in amyloplasts. At or near the 17th day mucilage appeared between the plasmalemma and the outer tangential wall of the epidermal cells. As the volume of mucilage increased, starch grains disappeared and were totally absent by 25 days. Membrane-bound structures and Golgi bodies were visible within the cytoplasm adjacent to the site of mucilage deposition. At maturity the seed epidermal cells were totally devoid of cytoplasm and engorged with mucilage.

The Distribution of Glycogen in the Tissues of Siboglinum Atlanticum [Pogonophora]

1973 ◽  
Vol 53 (3) ◽  
pp. 665-671 ◽  
Author(s):  
Eve C. Southward
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Epidermal Cells ◽  
Peritoneal Cells ◽  
Body Regions ◽  
Three Body

Light and electron microscopy showed the same distribution of glycogen. The peritoneal cells contain large amounts in all three body regions investigated: the forepart, metameric region and postannular region. Glycogen is present in most epidermal cells and is very abundant in some, particularly in the postannular region, but the cells which secrete the chitinous and proteinaceous components of the tube are almost devoid of glycogen.

Ontogeny of Alnus rubra – Alpova diplophloeus ectomycorrhizae. II. Transmission electron microscopy

1989 ◽  
Vol 67 (1) ◽  
pp. 201-210 ◽  
Author(s):  
H. B. Massicotte ◽  
C. A. Ackerley ◽  
R. L. Peterson
Keyword(s):  
Electron Microscopy ◽  
Epidermal Cells ◽  
Root Cap ◽  
Alnus Rubra ◽  
Golgi Bodies ◽  
Hartig Net ◽  
Transmission Electron ◽  
Meristem Zone ◽  
Basal Portion ◽  
Branching System

Ultrastructural features of the two symbionts in ectomycorrhizae formed between Alnus rubra and Alpova diplophloeus change with developmental stage. In the root cap – meristem zone, hyphae penetrate between vacuolated root cap cells and become appressed to epidermal cells containing small vacuoles, plastids with starch, numerous Golgi bodies, mitochondria, and endoplasmic reticulum cisternae. In the young Hartig net zone, hyphae with few vacuoles penetrate between vacuolated epidermal cells that still contain numerous Golgi bodies but now have plastids with small starch grains. Hartig net hyphae begin to branch and eventually form a complex branching system in the mature Hartig net zone. Hartig net hyphae in the basal portion of the ectomycorrhizae synthesize lipid and finally become vacuolated.

scholarly journals The Fine Structure of the Wheat Scutellum During Germination

1972 ◽  
Vol 25 (3) ◽  
pp. 469 ◽  
Author(s):  
JG Swift ◽  
TP O'brien
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Epithelial Cells ◽  
Light And Electron Microscopy ◽  
Cell Types ◽  
Wall Material ◽  
Cytological Evidence ◽  
Starch Grains ◽  
Parenchyma Cells ◽  
Cytological Changes

The cytological changes that take place in the scutellar epithelium and parenchyma during the first 5 days of germination are described by light and electron microscopy. Within 6 hr small starch grains appear in the plastids of both cell types and the size and number of starch grains increase gradually as germination proceeds. Later in germination starch disappears again from the plastids in the epithelial cells, but large starch grains still remain in the parenchyma cells. The reserves of the protein bodies are hydrolysed and the residual vacuoles undergo extensive coales-cence. Modifications in the appearance of the wall material of the epithelial cells as these cells elongate are illustrated and possible functional bases for these changes are suggested. The cells of the scutellar epithelium show no cytological evidence for their known functions of diastase secretion and nutrient absorption.

The structure of the antennal heart of Aedes aegypti (Linnaeus)

1997 ◽  
Vol 75 (3) ◽  
pp. 444-458 ◽  
Author(s):  
B. D. Sun ◽  
J. M. Schmidt
Keyword(s):  
Electron Microscopy ◽  
Connective Tissue ◽  
Aedes Aegypti ◽  
Light And Electron Microscopy ◽  
Single Layer ◽  
Epidermal Cells ◽  
Muscle Fibres ◽  
Columnar Cells

The structure of the antennal heart of Aedes aegypti (L.) (Diptera: Culicidae) was observed using light and electron microscopy. The antennal heart consists of several distinct regions including a single layer of columnar cells, the chamber walls, the valve, the z-body, the muscle fibres, and the connective tissue filaments. The columnar cells are structurally similar to secretory and osmoregulatory cells. Features of tendinous epidermal cells typically involved in the attachment of muscles to the cuticle can be observed in various areas of the antennal heart when it is examined as a whole. A model describing the pumping mechanism of the antennal heart in A. aegypti is presented.

scholarly journals Microstructure of Soft Scald in ‘Honeycrisp’ Apples

2017 ◽  
Vol 142 (6) ◽  
pp. 464-469
Author(s):  
Yin Xu ◽  
Yizhou Ma ◽  
Nicholas P. Howard ◽  
Changbin Chen ◽  
Cindy B.S. Tong ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cross Sections ◽  
Light And Electron Microscopy ◽  
Breeding Population ◽  
Epidermal Cells ◽  
Fruit Peel ◽  
Cellular Microstructure ◽  
Apple Cultivars ◽  
Honeycrisp Apples ◽  
Soft Scald

Soft scald is an apple (Malus ×domestica Borkh.) fruit disorder that appears in response to cold storage after about 2–8 weeks. It appears as a ribbon of dark tissue on the peel of the fruit, with occasional browning into the flesh. Several apple cultivars are susceptible to it, including Honeycrisp. The objectives of this study were to examine the cellular microstructure of fruit exhibiting soft scald and determine if any aspect of the peel microstructure at harvest could be indicative of future soft scald incidence. Light and electron microscopy were used to examine the peel microstructure of ‘Honeycrisp’ fruit that were unaffected or affected by soft scald. Tissue with soft scald had brown pigmented epidermal and hypodermal cells, whereas unaffected fruit peel epidermal cells were unpigmented. Cuticular wax of unaffected peel had upright wax platelets or clumps of wax, but peel surfaces with soft scald exhibited flattened granules and were more fragile than that of unaffected fruit. Epidermal cells of fruit with soft scald were more disorganized than that of unaffected fruit. Light microscopy was used to examine peels of ‘Honeycrisp’ fruit from four growing locations and fruit from a ‘Honeycrisp’ breeding population at harvest. ‘Honeycrisp’ and ‘Honeycrisp’ progeny fruit were also stored at 0 °C for 8 weeks and scored for soft scald incidence. Cross-sections of unaffected peel of stored ‘Honeycrisp’ fruit looked similar to that of freshly harvested fruit. No significant correlations were found between soft scald incidence and measured microstructural attributes of ‘Honeycrisp’ fruit at harvest, suggesting that peel microstructure cannot be used to predict possible soft scald incidence after storage.

scholarly journals Cargo crowding contributes to sorting stringency in COPII vesicles

2020 ◽  
Vol 219 (7) ◽  
Author(s):  
Natalia Gomez-Navarro ◽  
Alejandro Melero ◽  
Xiao-Han Li ◽  
Jérôme Boulanger ◽  
Wanda Kukulski ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Secretory Pathway ◽  
Light And Electron Microscopy ◽  
Secretory Proteins ◽  
Vesicle Size ◽  
Cargo Protein ◽  
Er Retention ◽  
Biophysical Process ◽  
Membrane Bound ◽  
Copii Vesicles

Accurate maintenance of organelle identity in the secretory pathway relies on retention and retrieval of resident proteins. In the endoplasmic reticulum (ER), secretory proteins are packaged into COPII vesicles that largely exclude ER residents and misfolded proteins by mechanisms that remain unresolved. Here we combined biochemistry and genetics with correlative light and electron microscopy (CLEM) to explore how selectivity is achieved. Our data suggest that vesicle occupancy contributes to ER retention: in the absence of abundant cargo, nonspecific bulk flow increases. We demonstrate that ER leakage is influenced by vesicle size and cargo occupancy: overexpressing an inert cargo protein or reducing vesicle size restores sorting stringency. We propose that cargo recruitment into vesicles creates a crowded lumen that drives selectivity. Retention of ER residents thus derives in part from the biophysical process of cargo enrichment into a constrained spherical membrane-bound carrier.

Studies on Pogonophora. Fine structure of the tentacles

1966 ◽  
Vol 46 (2) ◽  
pp. 351-372 ◽  
Author(s):  
Brij L. Gupta ◽  
Colin Little ◽  
Ann M. Philip
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Surface Membrane ◽  
Light And Electron Microscopy ◽  
Epidermal Cells ◽  
Mucous Cells

The structure of the tentacle in two species of Pogonophora (of the genera Nereilinum and Oligobrachia) has been investigated by light- and electron-microscopy. The fine structure of the pinnules, epidermal cells and mucous cells is described. The surface membrane of the epidermal cells and the pinnules forms an elaborate system of microvilli which traverse the cuticle and often extend up to the surface particles.

Ultrastructure of laticifers in seedlings of Glaucium flavum (Papaveraceae)

1982 ◽  
Vol 60 (5) ◽  
pp. 561-567 ◽  
Author(s):  
Craig L. Nessler
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Cell Differentiation ◽  
Wall Material ◽  
Starch Grains ◽  
Perforation Site ◽  
Dense Membrane ◽  
Membrane Bound ◽  
Unknown Composition

Laticifers in seedlings of Glaucium flavum Crantz were examined by electron microscopy. Laticifer initials first apeared in procambium of the radicle adjacent to the phloem about 48–72 h after germination. Differentiation of laticifer initials was characterized by the proliferation of numerous vesicles from dilation of endoplasmic reticulum. The usual complement of organelles was present in laticifer elements including a nucleus, mitochondria, dictyosomes, and plastids. Plastids were devoid of organized lamellae and starch grains but contained electron-dense, membrane-bound inclusions. Large crystalline bodies of unknown composition were also seen in the cytoplasm of some laticifer elements. Perforations were not observed in the longitudinal walls shared by adjacent laticifer elements; thus the laticifer system in this species can be classified as nonanastomosing. Transverse walls between laticifer elements remained intact until late in cell differentiation; however, large perforations did form in these walls as a result of the gradual removal of wall material at the perforation site.

A comparison of the death induced by fungal invasion or toxic chemicals in cowpea epidermal cells. II. Responses induced by Erysiphe cichoracearum

1988 ◽  
Vol 66 (4) ◽  
pp. 624-634 ◽  
Author(s):  
Susan L. F. Meyer ◽  
Michèle C. Heath
Keyword(s):  
Electron Microscopy ◽  
Cytoplasmic Streaming ◽  
Epidermal Cells ◽  
Toxic Chemicals ◽  
Ultrastructural Changes ◽  
Powdery Mildew Fungus ◽  
Fresh Tissue ◽  
Golgi Bodies ◽  
Erysiphe Cichoracearum ◽  
Cytoplasmic Aggregate

Cowpea leaves were inoculated with the plantain powdery mildew fungus, Erysiphe cichoracearum, and fresh epidermal cells overlying veins were examined by light microscopy before being cleared or prepared for electron microscopy. Fungal appressoria usually formed a haustorium in the underlying nonhost cell, but only after what appeared to be an unsuccessful penetration attempt that induced a transient cytoplasmic aggregate, a ring of autofluorescence in the plant wall (best seen in cleared tissue), and in two examples observed ultrastructurally, a small penetration peg embedded in a callose-like papilla. The haustorium developed from a different penetration peg and elicited the death of the invaded cell. As reported for the death of cowpea epidermal cells elicited by CuCl2, cytoplasmic changes that occurred rapidly in fresh tissue after cytoplasmic streaming had stopped correlated closely with changes in ultrastructure. Compared with the CuCl2 study, microtubules and Golgi bodies disappeared faster and membranes appeared more disorganized. These data suggest that in cowpea epidermal cells, ultrastructural changes accurately predict the onset of cell death and may also reflect differences in its modes of induction.

Structure and development of the spermatozoon of the parasitic nematode, Nematospiroides dubius

Parasitology ◽  
1985 ◽  
Vol 90 (1) ◽  
pp. 179-192 ◽  
Author(s):  
E. J. Wright ◽  
R. I. Sommerville
Keyword(s):  
Electron Microscopy ◽  
Germ Cells ◽  
Parasitic Nematode ◽  
Head Shape ◽  
Profound Change ◽  
Arrow Head ◽  
Golgi Bodies ◽  
Membrane Bound ◽  
Nematospiroides Dubius

Spermatogenesis and sperm maturation in Nematospiroides dubius were studied using electron microscopy. The testis is telegonic and germ cells in the zones of mitosis, growth and meiosis are connected by a central anucleate mass of cytoplasm, the rachis. The early part of spermatogenesis is dominated by the synthesis and growth of membrane-bound vesicles called membranous organelles, which originate from RER-associated Golgi bodies. Following meiosis the spermatids separate from the rachis and their chroinatin, which is no longer bounded by a nuclear envelope, condenses into an arrow-head shape and is extruded to form a tail-like structure. After insemination spermatozoa undergo a profound change called activation. The cytoplasmic region which was previously long and cylindrical becomes spherical and the membranous organelles which lined its perimeter fuse with the plasma membrane and become confined to the posterior hemisphere of the sperm, close to the nuclear tail. The anterior half of the sperm is devoid of organelles but contains many filaments organized into clumps and chains; this region being responsible for amoeboid locomotion of the sperm.

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