Development of the Suberized Lamella in the Mestome Sheath of Wheat Leaves

1975 ◽  
Vol 23 (5) ◽  
pp. 783 ◽  
Author(s):  
TP O'Brien ◽  
J Kuo
Keyword(s):  
Cell Walls ◽  
Tracheary Element ◽  
Tracheary Elements ◽  
Mestome Sheath ◽  
Suberized Lamella ◽  
Tangential Wall ◽  
Sieve Tubes ◽  
Wheat Leaves ◽  
Cytoplasmic Structures ◽  
Sheath Cells

The suberized lamella in the cell walls of the mestome sheath of wheat leaves developed asynchronously. The lamella formed first in the cells which were adjacent to the protophloem sieve tubes and formed last in the cells that abutted on the tracheary elements. In the latter case, the suberized lamella formed first in the outer tangential and radial walls and last in the inner tangential wall adjacent to the tracheary element. Eventually, the suberization was completed opposite the tracheary elements and the cell walls developed tertiary thickenings in all mestome sheath cells. Cytoplasmic structures that were clearly involved in suberin synthesis and the development of tertiary thickenings could not be identified.

Comparison between tracheary element lignin formation and extracellular lignin-like substance formation during the culture of isolated Zinnia elegans mesophyll cells

Biologia ◽  
2011 ◽  
Vol 66 (1) ◽  
Author(s):  
Yasushi Sato ◽  
Youko Yajima ◽  
Naohito Tokunaga ◽  
Ross Whetten
Keyword(s):  
Peroxidase Activity ◽  
Cell Walls ◽  
Vascular Plants ◽  
Culture Media ◽  
Tracheary Element ◽  
Zinnia Elegans ◽  
Tracheary Elements ◽  
Mesophyll Cells ◽  
Isolated Mesophyll Cells ◽  
Lignin Deposition

AbstractLignin is synthesized not only during morphogenesis of vascular plants but also in response to various stresses. Isolated Zinnia elegans mesophyll cells can differentiate into tracheary elements (TEs), and deposit lignin into cell walls in TE-inductive medium (D medium). Meanwhile isolated mesophyll cells cultured in hormone-free medium (Co medium) accumulate stress lignin-like substance during culture. Therefore this culture system is suitable for study of lignin and lignin-like substance formation.In D medium lignin was deposited in TEs, but in Co medium, extracellular lignin-like substance accumulated. Analysis of the culture media indicated the presence of dilignols in D culture, but not in Co culture. To investigate the fate of lignin precursors, we added coniferyl alcohol (CA) in each culture. In Co medium, CA was polymerized into dilignols rapidly but they were present only temporarily, and in D medium CA was polymerized into dilignols relatively slowly but their content increased continually.Meanwhile, in Co culture, peroxidase activity in the medium was much higher than the peroxidase activity bound ionically to the cell walls. In D culture, ionically bound peroxidase activity was higher than that in the medium. These results may suggest that lignin deposition in TEs is related to ionically bound peroxidases in D culture, and lignin-like substance deposition in the medium is related to peroxidases in the medium in Co culture.

Water Pathways in Wheat Leaves. IV. The Interpretation of Images of a Fluorescent Apoplastic Tracer

1988 ◽  
Vol 15 (4) ◽  
pp. 541 ◽  
Author(s):  
MJ Canny
Keyword(s):  
Cell Walls ◽  
Water Movement ◽  
Freeze Substitution ◽  
Sheath Cell ◽  
High Concentration ◽  
Mestome Sheath ◽  
Wheat Leaves ◽  
Apoplastic Tracer ◽  
Very High ◽  
Wall Components

Sections of wheat leaves fed with the fluorescent apoplastic tracer sulforhodamine G (SR) through the xylem were prepared by freeze-substitution and resin embedding. The distribution of fluorescence intensity (FI) of the tracer was measured by microspectrofluorometry at a resolution of 0.4 �m. SR was found to move within cell walls in restricted paths less than 200 nm wide. The name 'nanopaths' is suggested for these. The highest FI was found around the mestome-sheath / parenchyma-sheath border on the xylem side, and was shown to be due, not to binding of the tracer to wall components, but to the generation of a very high concentration of SR there by the separation of water from the solute. This separation cannot be evaporative but must be osmotic, and is presented as evidence of a major symplastic water movement starting at the parenchyma sheath cell membrane. The main resistance to water loss from the veins is at the mestome sheath and appears to be controlled by the suberised lamellae.

Occurrence of the Suberized Lamella in Leaves of Grasses of Different Photosynthetic Type. II. In Herbarium Material

1984 ◽  
Vol 32 (5) ◽  
pp. 465 ◽  
Author(s):  
PW Hattersley ◽  
S Perry
Keyword(s):  
Malic Enzyme ◽  
Cell Walls ◽  
Large Scale ◽  
Herbarium Specimens ◽  
Mestome Sheath ◽  
Carbon Reduction ◽  
Suberized Lamella ◽  
Living Material ◽  
Photosynthetic Type ◽  
Pep Carboxykinase

Dead air-dried leaves have been conventionally prepared for transmission electron microscopy to ascertain if the occurrence of a suberized lamella in cell walls can be detected. Our species sample includes representatives of all known photosynthetic types within the Poaceae (viz. C3, C4 NAD-malic enzyme type, C4 NADP-malic enzyme type and PEP carboxykinase type). Each photosynthetic type exhibits a characteristic pattern of suberized lamella occurrence in mestome sheath and/or 'photosynthetic carbon reduction' (PCR or 'Kranz') cell walls, consistent with that in fixed living material. Plasmodesmatal structure, and even on occasion chloroplast structure, is remarkably well preserved. Leaves from herbarium specimens, therefore, could be used to assign C4 species to their C4 acid decarboxylation type. This has potential application in large-scale systematic surveys for which living material may be difficult to obtain.

Structural aspects of tracheary element differentiation in suspension cultures of Zinnia elegans

1989 ◽  
Vol 47 ◽  
pp. 768-769
Author(s):  
C. H. Haigler ◽  
A. W. Roberts
Keyword(s):  
Tracheary Element ◽  
Vesicle Fusion ◽  
Zinnia Elegans ◽  
Cellulose Synthesis ◽  
Tracheary Elements ◽  
Animal Cells ◽  
Mesophyll Cells ◽  
Fixation Techniques ◽  
Localized Patterns ◽  
Structural Aspects

Tracheary elements, the water-conducting cells in plants, are characterized by their reinforced walls that became thickened in localized patterns during differentiation (Fig. 1). The synthesis of this localized wall involves abundant secretion of Golgi vesicles that export preformed matrix polysaccharides and putative proteins involved in cellulose synthesis. Since the cells are not growing, some kind of endocytotic process must also occur. Many researchers have commented on where exocytosis occurs in relation to the thickenings (for example, see), but they based their interpretations on chemical fixation techniques that are not likely to provide reliable information about rapid processes such as vesicle fusion. We have used rapid freezing to more accurately assess patterns of vesicle fusion in tracheary elements. We have also determined the localization of calcium, which is known to regulate vesicle fusion in plant and animal cells.Mesophyll cells were obtained from immature first leaves of Zinnia elegans var. Envy (Park Seed Co., Greenwood, S.C.) and cultured as described previously with the following exceptions: (a) concentration of benzylaminopurine in the culture medium was reduced to 0.2 mg/l and myoinositol was eliminated; and (b) 1.75ml cultures were incubated in 22 x 90mm shell vials with 112rpm rotary shaking. Cells that were actively involved in differentiation were harvested and frozen in solidifying Freon as described previously. Fractures occurred preferentially at the cell/planchet interface, which allowed us to find some excellently-preserved cells in the replicas. Other differentiating cells were incubated for 20-30 min in 10(μM CTC (Sigma), an antibiotic that fluoresces in the presence of membrane-sequestered calcium. They were observed in an Olympus BH-2 microscope equipped for epi-fluorescence (violet filter package and additional Zeiss KP560 barrier filter to block chlorophyll autofluorescence).

Lipid polymers accumulate in the epidermis and mestome sheath cell walls during low temperature development of winter rye leaves

PROTOPLASMA ◽  
1985 ◽  
Vol 125 (1-2) ◽  
pp. 53-64 ◽  
Author(s):  
Marilyn Griffith ◽  
N. P. A. Huner ◽  
K. E. Espelie ◽  
P. E. Kolattukudy
Keyword(s):  
Low Temperature ◽  
Cell Walls ◽  
Winter Rye ◽  
Sheath Cell ◽  
Mestome Sheath ◽  
Temperature Development

Comparison of photosynthetic carbon reduction (Kranz) cells having different ontogenetic origins in the C4 NADP – malic enzyme grass Arundinella hirta

1990 ◽  
Vol 68 (6) ◽  
pp. 1222-1232 ◽  
Author(s):  
Nancy G. Dengler ◽  
Ronald E. Dengler ◽  
Douglas J. Grenville
Keyword(s):  
Cell Walls ◽  
Vascular Tissue ◽  
Cell Types ◽  
Bundle Sheath ◽  
Carbon Reduction ◽  
Bundle Sheath Cells ◽  
Photosynthetic Carbon ◽  
Arundinella Hirta ◽  
Photosynthetic Carbon Reduction ◽  
Sheath Cells

The C4 grass Arundinella hirta is characterized by unusual leaf blade anatomy: photosynthetic carbon reduction takes place both within the chlorenchymatous bundle sheath cells of the longitudinal veins and within longitudinal strands of "distinctive cells" that form part of the leaf mesophyll and are often completely isolated from vascular tissue. Although they are equivalent physiologically, these two cell types have different ontogenetic origins: bundle sheath cells are delimited from procambium early in leaf development, whereas distinctive cells differentiate from ground meristem at a later developmental stage. Although the two cell types share numerous cytological features (large chloroplasts with reduced grana, thick cell walls with a suberin lamella), we also found significant differences in cell lengths, length to width ratios, cell cross-sectional areas, organelle numbers per cell cross section, phenol content of the cell walls, and numbers of pit fields in the longitudinal cell walls. The size and shape of bundle sheath cells are likely a direct consequence of procambial origin. The thicker walls of bundle sheath cells (in major veins) and their greater lignification may reflect the inductive effect of cell differentiation in the proximity of sclerenchyma and vascular tissues. Differences between major and minor vein bundle sheath cells may reflect differences in the timing of initiation of procambial strands. Our analysis of cell wall characteristics has also shown the presence of numerous primary pit fields in the transverse walls between adjacent distinctive cells in a file; plasmodesmata in these pit fields form a pathway for longitudinal symplastic transport not previously known to exist.

Maturation of the tracheary elements in the roots of Pinus banksiana and Eucalyptus grandis

2001 ◽  
Vol 79 (7) ◽  
pp. 844-849
Author(s):  
J H Taylor ◽  
C A Peterson
Keyword(s):  
Growth Rate ◽  
Root Growth ◽  
Pinus Banksiana ◽  
Eucalyptus Grandis ◽  
Tracheary Element ◽  
Reliable Indicator ◽  
Root Tip ◽  
Tracheary Elements ◽  
Fluorescent Tracer ◽  
Root Growth Rate

Tracheary elements of the xylem are responsible for the longitudinal (axial) transport of water and ions that have moved radially across the root. These vessel members and (or) tracheids mature some distance behind the root tip, and it is generally believed that this distance is directly related to root growth rate. To test this idea, the distances behind the root tip at which tracheary elements of pouch-grown Pinus banksiana Lamb. and Eucalyptus grandis W. Hill ex Maiden mature were examined. From each species, three root tip types (white, brown, and ectomycorrhizal short lateral) were assessed. Unlike previous studies of this topic, two methods of testing tracheary element maturity were employed concurrently. The first was anatomical and involved visualizing the deposition of lignin in the walls of the tracheids or vessel members. The second was functional and consisted of determining the capability of the tracheary elements to conduct a fluorescent, tracer dye. The distance behind the root tip at which the conductive xylem cells mature varied from 0.16 to 1.6 mm and was highly dependent on species and root type. No significant correlation was found between growth rate and proximity of tracheary element maturation to the tip for white roots. The presence of lignin in the tracheary element wall was not a reliable indicator of the cell's functional maturity.Key words: conductivity, development, roots, tracheary elements, xylem.

scholarly journals Nectar secretion in a dry habitat: structure of the nectary in two endangered Mexican species of Barkeria (Orchidaceae)

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11874
Author(s):  
Małgorzata Stpiczyńska ◽  
Magdalena Kamińska ◽  
Kevin L. Davies
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Habitat Structure ◽  
Nectar Secretion ◽  
Micro Channels ◽  
Tangential Wall ◽  
Secretory Tissue ◽  
Floral Nectaries ◽  
Structural Adaptations ◽  
Mexican Species

Barkeria scandens and B. whartoniana are endangered, endemic taxa from Mexico. They are epiphytes adapted to dry habitats. Since these plants are xerophytic, their flowers were investigated for structural adaptations to nectar secretion. The flowers of both species are structurally similar, and contrary to most claims for the genus, have functional floral nectaries comprising a nectary chamber and a narrow tubular cuniculus. Nectar is present in both these structures, and contains sugars and lipid-like compounds. The nectary tissue is composed of a single-layered epidermis overlying 1–2 layers of subepidermal secretory parenchyma. The outer tangential wall of the epidermal cells is thick and multi-layered, whereas the cuticle, which often shows blistering, is lamellate and possesses micro-channels. Lipid-like material occurs both between the microfibrils of the cell wall and in the micro-channels. Robust secretory tissue, thick cell walls, and lipid-like nectar components limit nectar evaporation. Moreover, the rigidity of the nectary potentially makes it possible for red-flowered B. scandens to switch from entomophily to ornithophily.

Sign in / Sign up

Export Citation Format

Share Document