The morphogenesis of substomatal structures in Polypodium vulgare

1977 ◽  
Vol 55 (23) ◽  
pp. 2873-2878 ◽  
Author(s):  
R. A. Stevens ◽  
E. S. Martin
Keyword(s):  
Functional Capacity ◽  
Guard Cell ◽  
Early Stage ◽  
Guard Cells ◽  
Cell Complex ◽  
Stomatal Development ◽  
Stomatal Complex

The development of substomatal sacs and the capacity of the underlying ion-adsorbent sites to accumulate potassium is examined in relation to the ontogeny of the stomatal complex and mature guard cells of the fern, Polypodium vulgare. It is suggested that while the substomatal structures are formed at an early stage of stomatal development, their functional capacity may not be fully realised until the guard cell complex is fully matured.

Stomatal ontogeny and morphology in Phaseolus vulgaris in relation to infection structure initiation by Uromyces appendiculatus

1991 ◽  
Vol 69 (3) ◽  
pp. 477-484 ◽  
Author(s):  
B. T. Terhune ◽  
E. A. Allen ◽  
H. C. Hoch ◽  
W. P. Wergin ◽  
E. F. Erbe
Keyword(s):  
Electron Microscopy ◽  
Phaseolus Vulgaris ◽  
Guard Cells ◽  
Uromyces Appendiculatus ◽  
Stomatal Development ◽  
Appressorium Formation ◽  
Stomatal Complex ◽  
Thin Sections ◽  
Transmission Electron ◽  
Stomatal Guard Cells

The development and morphology of the stomatal complex in Phaseolus vulgaris was examined by light microscopy, scanning electron microscopy, and transmission electron microscopy (TEM). The outer aperture formed between the stomatal guard cells was bordered by cuticular ledges, 1.2–5.3 μm wide. These were composed of a matrix of electron-dense fibrils supporting an autofluorescent amorphous outer layer, homologous to the cuticle. This layer of cuticle lined the ventral walls of the guard cells and extended into the substomatal chamber. During stomatal development, as the guard cells separated, the outer cuticular layer covering the incipient aperture stretched and split, forming stomatal lips. These lips, 0.2–1.4 μm wide, were oriented horizontally, upright, and folded back from the ledge in TEM thin sections. In cryopreserved stomata, the lips were generally oriented upright regardless of whether the outer aperture was open or closed. Previous studies have implicated that stomatal lips may function to signal appressorium formation in urediniospore germlings of Uromyces appendiculatus. This study indicated that dimensions of the lips were within the parameters required to induce appressorium formation on artificial membranes. Other components of the stomatal architecture may also be involved in the induction of appressorium formation. Key words: Uromyces appendiculatus, Phaseolus vulgaris, stomata, cuticle, appressoria.

Characterization of stomatal development in Dianthus chinensis

1988 ◽  
Vol 66 (1) ◽  
pp. 142-149 ◽  
Author(s):  
Thalia Pappas ◽  
Patricia McManus ◽  
Peter Vanderveer ◽  
Judith Croxdale
Keyword(s):  
Leaf Blade ◽  
Leaf Surface ◽  
Guard Cells ◽  
Stomatal Development ◽  
Stomatal Frequency ◽  
Stomatal Complex ◽  
Adaxial Surface ◽  
Abaxial Leaf Surface ◽  
Area Basis

Stomatal differentiation in Dianthus chinensis leaves was characterized structurally and functionally using plants of the seventh plastochron. Development of stomata was followed using scanning electron microscopy. The maturity of the stomatal complex, the existence of an open stomatal pore, and the localization of K+ within guard cells were used as indicators of stomatal function. The results showed that stomatal development spanned a 10- to 12-day period, which began on the fourth youngest pair of leaves and was completed in the middle of the blade of the sixth youngest leaf pair where stomatal function was acquired. Stomatal frequency on an area basis decreased from the base to the tip of the leaf blade and from the abaxial to the adaxial surface of the leaf. There was a 10-fold decline in the frequency of stomata during leaf maturation; frequency on the abaxial leaf surface was about twice that on the adaxial surface. Dimensions of the antechamber aperture changed during development but at maturity exhibited a range of lengths and widths that was independent of stomatal location on the leaf. The localization of K+ in guard cells occurred only in the later stages of differentiation and was absent in stomata of senescing leaves.

Microtubule Orientation During Stomatal Differentiation in Grasses

1989 ◽  
Vol 92 (4) ◽  
pp. 581-594
Author(s):  
SOON-OK CHO ◽  
SUSAN M. WICK
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Guard Cell ◽  
Mother Cell ◽  
Early Stage ◽  
Preprophase Band ◽  
Subsidiary Cell ◽  
Stomatal Complex ◽  
Face View ◽  
Mother Cells

The changing orientation of microtubules (MTs) during formation of the stomatal complex in grasses was observed by immunofluorescence microscopy, beginning with the asymmetrical division of the cell that gives rise to the guard cell mother cell, i.e. the guard cell grandmother cell. The asymmetrically placed preprophase band (PPB) of guard cell grandmother cells and hair cell mother cells is always laid down parallel to the distal end wall even when this wall is oblique to the long axis of the cell. The first step in formation of the PPB of a subsidiary cell mother cell appears to be establishment of an incomplete band of MTs. Whereas the mature PPB forms a curved line in a face view of a subsidiary cell mother cell, in this early stage MTs form fan-shaped arrays that focus on two points along the edge of the subsidiary cell mother cell. Replacement of the transversely oriented interphase microtubule band of the guard cell mother cell with the longitudinally oriented PPB involves several distinctive stages: (1) appearance of MTs directed toward the centre of the periclinal surface along the entire length of the lateral walls. (2) Appearance of another set of MTs along the entire width of both end walls, likewise focused toward the centre of the periclinal surface. Together these two groups of MTs form a cross with broadened tips in face view of the leaf. (3) Disappearance of the first set of MTs, and formation of an increasingly narrow band from the latter at the site of future cytokinesis. Although the anaphase spindles of guard cell grandmother cells, hair cell mother cells and guard cell mother cells are usually diagonally oriented relative to the site occupied previously by the PPB, the line connecting the centres of the spindle poles that are established at prophase is perpendicular to the persisting PPBs. Unlike the situation in certain other hair cells, MTs in leaf hair cells are transversely oriented even when the cells are highly elongated.

Osmocytosis and Vacuolar Fragmentation in Guard Cell Protoplasts: Their Relevance to Osmotically-lnduced Volume Changes in Guard Cells

1993 ◽  
Vol 44 (10) ◽  
pp. 1569-1577 ◽  
Author(s):  
WILFRIED DIEKMANN ◽  
RAINER HEDRICH ◽  
KLAUS RASCHKE ◽  
DAVID G. ROBINSON
Keyword(s):  
Guard Cell ◽  
Guard Cells ◽  
Volume Changes ◽  
Guard Cell Protoplasts

Abstract 6262: Obesity in Childhood is Associated With an Impaired Regenerative Capacity of Circulating Progenitor Cells and Vascular Dysfunction

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Sandra Erbs ◽  
Robert Höllriegel ◽  
Axel Linke ◽  
Agnieszka Burman ◽  
Daniela Friebe ◽  
...  
Keyword(s):  
Childhood Obesity ◽  
Progenitor Cells ◽  
Functional Capacity ◽  
Early Stage ◽  
Serum Insulin ◽  
Reactive Hyperemia ◽  
Oral Glucose ◽  
Obese Children ◽  
Regenerative Capacity ◽  
Lean Children

The raising prevalence of obesity in childhood appears to preceed the development of atherosclerosis and the increased incidence of cardiovascular diseases in adulthood. This might be related to the fact that already in children, obesity is associated with classical risk factors for coronary disease, like hypertension, hyperlipidemia, or diabetes. Therefore, aim of the present study was to evaluate, whether obese children (compared to lean controls) are characterized by vascular damages and altered regenerative capacity of circulating endothelial progenitor cells (CPCs) as an early indicator of developing atherosclerosis. Methods: In 30 obese (11±3 years of age, BMI 28.1±1.3) and 30 lean control children (12±3 years of age, BMI 17.5±0.4) insulin sensitivity was evaluated by oral glucose tolerance testing (OGT). Peripheral flow-mediated dilatation (FMD) and intima media thickness (IMT) of the carotid artery were assessed as measures of vascular integrity. The number of CD34/KDR+ CPCs was quantified using FACS analysis and the functional capacity of CPCs was determined by migration assay. Results: Obesity in early childhood is associated with peripheral insulin resistance as an early manifestation of diabetes (serum insulin in OGT after 120 min: 543±102 pmol/L in obese vs. 275±39 pmol/L in lean, p<0.05). FMD was significantly impaired in obese compared to lean children (reactive hyperemia index 1.25±0.05 vs. 1.55±0.08, p<0.05). Already in childhood, obesity was accompanied by a gain in IMT (0.40±0.01 mm vs. 0.30±0.01 mm in lean, p<0.05). Obese children had significantly reduced numbers of circulating CPCs compared to lean children (70±7 vs. 119±13 cells/mL blood, p<0.05). There was an inverse correlation between the number of CPCs and the extent of obesity as determined by BMI-SDS (r=−0.27, p<0.05). Additionally, functional capacity of CPCs was significantly reduced in obese children (migration following a SDF-1 gradient: 170±31 CPCs/1000 plated CPCs in obese vs. 258±37 CPCs/1000 plated CPCs in lean, p<0.05). Conclusion: Already in childhood, obesity is associated with an impaired endogenous regenerative capacity, which might result in generalized vascular damage as an early stage of atherosclerosis.

scholarly journals Stomatal Development in Aerial Axes of Psilotum nudum (Psilotaceae)

2012 ◽  
Vol 128 (3-4) ◽  
pp. 95-99 ◽  
Author(s):  
James E. Mickle ◽  
Maria Rosaria Barone Lumaga ◽  
Paolo De Luca
Keyword(s):  
Electron Microscopy ◽  
Guard Cells ◽  
Cytoplasmic Protein ◽  
Stomatal Development ◽  
Wax Deposition ◽  
Psilotum Nudum ◽  
Pd Alloy ◽  
Entire Cell ◽  
Mother Cells ◽  
Scanning Electron

Abstract Apical regions of developing aerial shoots of Psilotum nudum (L.) Beauv. were studied using both scanning electron microscopy (SEM) and light microscopy (LM) with the aim of improving our understanding of early stages in stomatal and epidermal ontogenesis. SEM samples were fixed in gluteraldehyde, critical point dried, and coated with an Au-Pd alloy. LM samples were fixed in FAA and embedded in paraffin. LM sections were stained with 0.05% toluidine blue for protein. SEM shows that P. nudum stomata develop from 20 µm-long domed meristemoid cells into guard cell mother cells (GMCs). A furrow dividing guard cells develops at 30 µm long, and wax deposition that will cover the entire cell begins at 70 µm long. LM longitudinal sections of GMCs show a cytoplasmic protein net that organizes into radial fibers, similar to reports of actin fibers in stomata of angiosperms. This study provides additional details of stomatal development in Psilotum and is the first report of an actin-like protein net in Psilotum.

scholarly journals Guard Cell Microfilament Analyzer Facilitates the Analysis of the Organization and Dynamics of Actin Filaments in Arabidopsis Guard Cells

2019 ◽  
Vol 20 (11) ◽  
pp. 2753
Author(s):  
Xin Li ◽  
Min Diao ◽  
Yanan Zhang ◽  
Guanlin Chen ◽  
Shanjin Huang ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Dynamic Behavior ◽  
Guard Cell ◽  
Actin Filaments ◽  
De Novo ◽  
Guard Cells ◽  
Stomatal Movement ◽  
Selection Of

The actin cytoskeleton is involved in regulating stomatal movement, which forms distinct actin arrays within guard cells of stomata with different apertures. How those actin arrays are formed and maintained remains largely unexplored. Elucidation of the dynamic behavior of differently oriented actin filaments in guard cells will enhance our understanding in this regard. Here, we initially developed a program called ‘guard cell microfilament analyzer’ (GCMA) that enables the selection of individual actin filaments and analysis of their orientations semiautomatically in guard cells. We next traced the dynamics of individual actin filaments and performed careful quantification in open and closed stomata. We found that de novo nucleation of actin filaments occurs at both dorsal and ventral sides of guard cells from open and closed stomata. Interestingly, most of the nucleated actin filaments elongate radially and longitudinally in open and closed stomata, respectively. Strikingly, radial filaments tend to form bundles whereas longitudinal filaments tend to be removed by severing and depolymerization in open stomata. By contrast, longitudinal filaments tend to form bundles that are severed less frequently in closed stomata. These observations provide insights into the formation and maintenance of distinct actin arrays in guard cells in stomata of different apertures.

scholarly journals Preparation of Rolled Epidermis of Vicia Faba L. So That Stomata are the Only Viable Cells: Analysis of Guard Cell Potassium by Flame Photometry

1973 ◽  
Vol 26 (2) ◽  
pp. 309 ◽  
Author(s):  
WG Allaway ◽  
TC Hsiao
Keyword(s):  
Vicia Faba ◽  
Guard Cell ◽  
Guard Cells ◽  
Flame Photometry ◽  
Viable Cells ◽  
Rolling Technique ◽  
Vicia Faba L

A rolling technique is described with which cells in epidermal strips of V. faba were differentially broken so that only guard cells remained alive and functional. In rolled epidermis potassium was retained only in live guard cells, as judged by staining with cobaltinitrite.

The occurrence of functional non-chlorophyllous guard cells in Paphiopedilum spp.

1975 ◽  
Vol 53 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Sherman D. Nelson ◽  
James M. Mayo
Keyword(s):  
Fluorescence Microscopy ◽  
Blue Light ◽  
Guard Cell ◽  
Direct Evidence ◽  
Light Response ◽  
Guard Cells ◽  
Epidermal Cells ◽  
Stomatal Response ◽  
Intact Leaves ◽  
Stomatal Functioning

Hypostomatous lady slipper orchids, Paphiopedilum spp., were found to have non-chlorophyllous epidermal cells, including guard cells. The lack of chlorophyll within the guard cells was demonstrated by fluorescence microscopy. A "normal" chlorophyllous mesophyll was present. The leaf resistances of intact leaves were about 5–10 s cm−1 in the light and were greater than 100 s cm−1 in the dark, indicating light opening and dark closure of the stomata. A CO2-dependent stomatal response (i.e., a tendency to close at elevated CO2 levels) was demonstrated, as was a CO2-independent light response (i.e., greater opening in blue light than in red). This provides direct evidence to support the idea that guard cell chlorophyll is not necessary for stomatal functioning.

Ultrastructural observations on guard cells of Vicia faba and Allium porrum

1972 ◽  
Vol 50 (6) ◽  
pp. 1405-1413 ◽  
Author(s):  
W. G. Allaway ◽  
George Setterfield
Keyword(s):  
Vicia Faba ◽  
Small Groups ◽  
Guard Cell ◽  
Cell Walls ◽  
Guard Cells ◽  
Cell Physiology ◽  
Allium Porrum ◽  
Starch Granules ◽  
Mesophyll Cells ◽  
Guard Cell Chloroplasts

Stomata of Vicia faba and Allium porrum were examined in thin section with the electron microscope. Guard cells contained numerous mitochondria, few plastids, and relatively small vacuoles traversed by many strands of cytoplasm. Spherosomes were often observed but were variable in occurrence. Endoplasmic reticulum and dictyosomes were present, although not well developed. Scattered microtubules were present at the periphery of the cells. Microbodies were very rarely observed in guard cells and no plasmodesmata were ever seen in the guard cell walls. Plastids were small and irregular in outline in guard cells of both species. Guard cell plastids of V. faba contained abundant large starch granules. In both species thylakoids were few and grana were small in comparison with mesophyll plastids. The inner of the two bounding membranes of guard cell chloroplasts was extensively invaginated, forming a peripheral reticulum. This was not observed in mesophyll plastids of these species. Small groups of microtubule-like structures were often observed in V. faba guard cell plastids; microtubule-like structures were less frequent in A. porrum plastids, and were not in groups. The structures described are compared with those of other epidermal cells and mesophyll cells, and are discussed in relation to guard cell physiology.

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