Side branch formation and orientation in the caulonema of the moss,Funaria hygrometrica: Normal development and fine structure

PROTOPLASMA ◽  
1979 ◽  
Vol 100 (3-4) ◽  
pp. 367-383 ◽  
Author(s):  
G. Schmiedel ◽  
E. Schnepf
Keyword(s):  
Fine Structure ◽  
Normal Development ◽  
Side Branch ◽  
Funaria Hygrometrica ◽  
Branch Formation ◽  
Side Branch Formation

scholarly journals The Ascus Apex in Lichenized Fungi III. The Pertusaria-Type

1982 ◽  
Vol 14 (3) ◽  
pp. 205-217 ◽  
Author(s):  
Rosmarie Honegger
Keyword(s):  
Fine Structure ◽  
Side Branch ◽  
Functional Type ◽  
Electron Microscopic ◽  
Considerable Heterogeneity ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Scanning Electron Microscopic ◽  
Elongation Process ◽  
Scanning Electron

AbstractOn the basis of light microscopic (LM), scanning electron microscopic (SEM) and transmission electron microscopic (TEM) investigations the Pertusaria-type of ascus is described as a particular functional type. The functionally unitunicate Pertusaria-type is characterized by its structure, staining properties, and by its particular mode of dehiscence. Tripartite ascus walls were observed in LM and TEM. The non-amyloid ascus wall is surrounded by a thin, amyloid outer layer. Both become amorphous at maturity and partly disintegrate. An apically thickened, amyloid inner layer reaches the base of the ascus. In its fine structure this amyloid inner layer resembles the material of the amyloid dome of Lecanora-type asci. It plays an important role during dehiscence and spore discharge. An elongation process was observed prior to dehiscence, at the end of which the ascus tip is situated above the hymenial surface. Dehiscence occurs by bursting or splitting of the whole ascus tip. The Pertusaria-type might represent a side-branch of evolution from bitunicate to unitunicate forms within the Lecanorales.Pertusaria-type asci are restricted to a small number of genera within the Pertusariaceae. A considerable heterogeneity in ascus structure and staining properties was observed within the Pertusariineae sensu Henssen & Jahns (1973) and Henssen (1976).

Visualization of the endoplasmic reticulum in living buds and branches of the moss Funaria hygrometrica by confocal laser scanning microscopy

Development ◽  
1990 ◽  
Vol 109 (4) ◽  
pp. 753-764
Author(s):  
M.M. McCauley ◽  
P.K. Hepler
Keyword(s):  
Endoplasmic Reticulum ◽  
Confocal Laser Scanning Microscopy ◽  
Laser Scanning ◽  
Side Branch ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Scanning Microscopy ◽  
Confocal Laser ◽  
Funaria Hygrometrica ◽  
Bud Formation

Caulonemata of the moss Funaria hygrometrica were vitally stained with the fluorescent, lipophilic carbocyanine dye DiOC6(3) and examined via confocal laser scanning microscopy. Although DiOC6(3) stained nearly all of the organelles, cortical endoplasmic reticulum (ER) could be resolved under favorable conditions and appeared as a network of irregular polygons, interspersed with lamellar cisternae in some cell types. The pattern of cortical ER was examined first during side initial formation and then in young branches and buds. The ER network extends into the outgrowth of a developing side initial, keeping pace with elongation of the outgrowth. Prior to the cell division that cuts off the outgrowth from the underlying cell, the network in the outgrowth becomes tighter, i.e. the polygons become smaller. If the side initial develops as a branch, this somewhat tighter ER network is maintained in the tip-growing side branch. If the side initial develops as a bud, dramatic changes in both the configuration and the quantity of the ER network occur. Coincident with the apical swelling that marks the first visible sign of bud formation, the network becomes increasingly tighter until eventually the polygonal configuration is barely discernible. The increased coverage of the bud cortex by the ER network demonstrates that a significant increase in the quantity of membranes also takes place during bud formation in Funaria.

scholarly journals CHANGES IN CELL FINE STRUCTURE DURING LENS REGENERATION IN XENOPUS LAEVIS

1965 ◽  
Vol 24 (2) ◽  
pp. 211-222 ◽  
Author(s):  
Jane Overton
Keyword(s):  
Fine Structure ◽  
Xenopus Laevis ◽  
Normal Development ◽  
Low Density ◽  
Morphological Complexity ◽  
Lens Fibers ◽  
Lens Regeneration ◽  
Lens Vesicle ◽  
Rough Er ◽  
Two Phases

Changes at the level of cell fine structure have been studied during lens regeneration in the toad, Xenopus laevis, where cornea gives rise to the new lens. The transformation of these cells may be divided into three phases. (1) In the cornea, flattened cells become cuboidal and rough endoplasmic reticulum increases in amount. (2) In the new lens vesicle, cisternae of the rough ER break down into vesicles, smooth-walled vesicles and free ribosomes increase in number, and mitochondria can become enlarged and irregular, then centrally attenuated. Rudimentary cilia form. (3) As new lens fibers form, ribosomes become very numerous and low density fibrous elements and dense clumps appear in the cytoplasm. These phases are accompanied by marked nucleolar changes. The changes during the 3rd phase are similar to changes in the lens during normal development. The first two phases show an unexpected morphological complexity.

Nerve fibre regeneration after traumatic lesions of the CNS; progress and problems

1991 ◽  
Vol 331 (1261) ◽  
pp. 303-306 ◽  
Keyword(s):  
Synapse Formation ◽  
Target Recognition ◽  
Side Branch ◽  
Distal Dendrite ◽  
Long Distance ◽  
Axon Sprouting ◽  
Lower Vertebrates ◽  
Traumatic Lesions ◽  
Branch Formation ◽  
Selection Of

Four distinct phases can be distinguished in the regenerative response of a lesioned CNS axon: sprouting of the proximal axon stump, elongation, target recognition, and formation of appropriate synapses. These processes can be observed in such a way only in lower vertebrates, in particular, in the optic system. In these species and systems, both, the guidance mechanisms leading regenerating fibres to their former target areas, and the mechanisms responsible for specific synapse formation are retained throughout life. As during development, guidance crucially depends on the presence of favourable substrate molecules, and on chemotropic signals (Dodd & Jessel 1989; Tessier-Lavigne et al .1988; Harris 1989). The cell biological mechanisms responsible for target recognition including the arrest of long-distance growth, the initiation of side branch formation and terminal arborization, and the selection of specific post-synaptic partners (cell type; soma, proximal or distal dendrite, spines, axons) remain unknown up to now.

scholarly journals Fine structure of kinetin-treated protonema and kinetin-induced gametophore buds in Funaria hygrometrica

2015 ◽  
Vol 40 (4) ◽  
pp. 549-555 ◽  
Author(s):  
F. Młodzianowski ◽  
A. Szweykowska
Keyword(s):  
Fine Structure ◽  
Metabolic Activity ◽  
The Other ◽  
Funaria Hygrometrica ◽  
Other Hand ◽  
Bud Induction ◽  
Development And Differentiation ◽  
High Metabolic Activity

Besides occasional hypertrophy of grana and disintegration of stroma thylakoids occurring in some chloroplasts, no significant changes were found in ultrastructure of typical protonema cells treated for six days with kinetin. On the other hand, the fine structure of cells in kinetin--induced gametophore buds differed much from that of the protonema cells and showed characteristics of cells of with high metabolic activity and high division rates. The results indicate that cytokinins enhance development and differentiation in the protonema by activating only some of its cells, whereas the others remain unchanged or show symptoms of destruction and ageing. This is supported by the fact that in the presence of chloramphenicol, which prevents bud induction, kinetin acts synergistically with the inhibitor in producing degeneration and destruction of chloroplasts.

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