scholarly journals Seed coat development in explosively dispersed seeds of Cardamine hirsuta

2019 ◽  
Vol 126 (1) ◽  
pp. 39-59
Author(s):  
Ulla Neumann ◽  
Angela Hay
Keyword(s):  
Seed Coat ◽  
Cell Walls ◽  
Outer Integument ◽  
Immunogold Labelling ◽  
Microscopical Level ◽  
Seed Surface ◽  
Electron Microscopical Level ◽  
Cell Layers ◽  
Electron Microscopical ◽  
Ballistic Dispersal

Abstract Background and Aims Seeds are dispersed by explosive coiling of the fruit valves in Cardamine hirsuta. This rapid coiling launches the small seeds on ballistic trajectories to spread over a 2 m radius around the parent plant. The seed surface interacts with both the coiling fruit valve during launch and subsequently with the air during flight. We aim to identify features of the seed surface that may contribute to these interactions by characterizing seed coat differentiation. Methods Differentiation of the outermost seed coat layers from the outer integuments of the ovule involves dramatic cellular changes that we characterize in detail at the light and electron microscopical level including immunofluorescence and immunogold labelling. Key Results We found that the two outer integument (oi) layers of the seed coat contributed differently to the topography of the seed surface in the explosively dispersed seeds of C. hirsuta vs. the related species Arabidopsis thaliana where seed dispersal is non-explosive. The surface of A. thaliana seeds is shaped by the columella and the anticlinal cell walls of the epidermal oi2 layer. In contrast, the surface of C. hirsuta seeds is shaped by a network of prominent ridges formed by the anticlinal walls of asymmetrically thickened cells of the sub-epidermal oi1 layer, especially at the seed margin. Both the oi2 and oi1 cell layers in C. hirsuta seeds are characterized by specialized, pectin-rich cell walls that are deposited asymmetrically in the cell. Conclusions The two outermost seed coat layers in C. hirsuta have distinct properties: the sub-epidermal oi1 layer determines the topography of the seed surface, while the epidermal oi2 layer accumulates mucilage. These properties are influenced by polar deposition of distinct pectin polysaccharides in the cell wall. Although the ridged seed surface formed by oi1 cell walls is associated with ballistic dispersal in C. hirsuta, it is not restricted to explosively dispersed seeds in the Brassicaceae.

Ultrastructural localization of neuropeptides in the rat brain

1978 ◽  
Vol 36 (2) ◽  
pp. 612-613
Author(s):  
F.W. Van Leeuwen
Keyword(s):  
Freeze Substitution ◽  
Ultrastructural Localization ◽  
Serial Sections ◽  
Microscopical Level ◽  
Electron Microscopical Level ◽  
Enzyme Method ◽  
Perfusion Fixation ◽  
Electron Microscopical ◽  
Unlabeled Antibody ◽  
Peroxidase Conjugate

In order to obtain specific and optimal ultrastructural localization of vasopressin and oxytocin in the hypothalamo-neurohypophyseal system of the rat, 2 staining procedures and several tissue treatments were evaluated using neurohypophyseal tissue. It appeared from these studies that post-embedding staining with the unlabeled antibody enzyme method developed by Sternberger allows greater dilution of the first antibody (anti-vasopressin, 1:4800) than the indirect procedure (1:320) using a peroxidase conjugate as second antibody. Immersion fixation with 4% formalin during 24 hours gave better results (general ultrastructure, immunoreactivity) than those obtained by perfusion fixation with 2.5% glutaraldehyde-1% paraformaldehyde or freeze substitution.Since no reliable specificity tests were performed at the electron microscopical level, tests were developed for antibodies against both vasopressin and oxytocin. For anti-vasopressin plasma neural lobes of homozygous Brattleboro rats, that are lacking vasopressin by a genet- ical defect, were used. For antibodies against both hormones serial sections were used that were alternately incubated with the antibodies.

SOME LIGHT- AND ELECTRON-MICROSCOPICAL OBSERVATIONS ON THE PARS TUBERALIS OF THE PITUITARY GLAND OF THE RABBIT

1972 ◽  
Vol 54 (3) ◽  
pp. 505-511 ◽  
Author(s):  
E. CAMERON ◽  
C. L. FOSTER
Keyword(s):  
Interstitial Cell ◽  
Secretory Granules ◽  
The Other ◽  
Neurosecretory Material ◽  
Pars Tuberalis ◽  
Nerve Fibres ◽  
Microscopical Level ◽  
Electron Microscopical Level ◽  
Irregular Nucleus ◽  
Electron Microscopical

SUMMARY The cytological appearance of the pars tuberalis both at the light- and the electron-microscopical levels is described. Two main types of cell, one, which is designated the tuberalis cell, having a rounded contour, pale cytoplasm with a few small secretory granules of about 100 nm in diameter, many polyribosomes and a relatively large ovoid nucleus; and the other, the interstitial cell, with long processes often encircling tuberalis cells, an irregular nucleus and cytoplasm with abundant microfilaments about 10 nm in diameter were seen. Beaded nerve fibres and neurosecretory material were demonstrated in the pars tuberalis with chrome alum—haematoxylin, a finding confirmed at the electron-microscopical level where nerve fibres which appeared to be making contact with tuberalis cells and containing numerous microvesicles of about 50 nm in diameter were observed.

Micromorphometric Determination of Organelles and of Storage Material in Wood Ray Cells - A Useful Method for Detecting Differentiation Within a Tissue

IAWA Journal ◽  
1989 ◽  
Vol 10 (4) ◽  
pp. 395-403 ◽  
Author(s):  
Jörg J. Sauter ◽  
Barbara van Cleve
Keyword(s):  
Individual Cell ◽  
Cell Types ◽  
Storage Material ◽  
Cell Organelles ◽  
Microscopical Level ◽  
Storage Compounds ◽  
Electron Microscopical Level ◽  
Ray Cells ◽  
Electron Microscopical

The size and distribution of individual cell organelles (plastids, mitochondria, oleosomes, protein bodies) and of the three main storage compounds (starch, fat, protein) have been studied micromorphometrically at the electron microscopical level in ray cells of poplar wood during early winter. The three cell types of the rays (contact cells, isolation cells, cells of the contact cell rows) show remarkable differences in size and distribution of organelles and of storage material which manifest an existing physiological specialisation of these cells. The micromorphometric data on storage compounds are compared with the biochemically determined amounts of starch, proteins, fat-bound glycerol, and of various sugars in the wood. At the stage investigated, a prominent protein storage, an extensive starch-sugar transition, but no indications for a starch-fat transition are found. Micromorphometry proved to be a useful tool for the detection of cell-specific differences within a tissue.

Immunocytochemical localization of dopamine in the prefrontal cortex of the rat at the light and electron microscopical level

Neuroscience ◽  
1987 ◽  
Vol 22 (3) ◽  
pp. 849-862 ◽  
Author(s):  
C.G. Van Eden ◽  
E.M.D. Hoorneman ◽  
R.M. Buijs ◽  
M.A.H. Matthijssen ◽  
M. Geffard ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Immunocytochemical Localization ◽  
Microscopical Level ◽  
Electron Microscopical Level ◽  
Electron Microscopical

Acid Phosphatase Activity in the Neutral Red Granules of Mouse Exocrine Pancreas Cells

1964 ◽  
Vol s3-105 (71) ◽  
pp. 343-348
Author(s):  
JENNIFER M. BYRNE
Keyword(s):  
Acid Phosphatase ◽  
Phosphatase Activity ◽  
Acid Phosphatase Activity ◽  
Exocrine Pancreas ◽  
Neutral Red ◽  
Pancreatic Tissue ◽  
Microscopical Level ◽  
Electron Microscopical Level ◽  
Electron Microscopical

The Gomori test for acid phosphatase was performed on pancreatic tissue from mice injected with neutral red. On an electron microscopical level, acid phosphatase activity was found to be localized in the neutral red granules. It is suggested that the neutral red granules are of lysosomal derivation.

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