Formation of the oblique spindle in dividing guard mother cells ofAllium

PROTOPLASMA ◽  
1988 ◽  
Vol 147 (2-3) ◽  
pp. 200-203 ◽  
Author(s):  
Y. Mineyuki ◽  
J. Marc ◽  
B. A. Palevitz
Keyword(s):  
Guard Mother Cells ◽  
Mother Cells

Comparative effects of phalloidin and cytochalasin B on motility and morphogenesis in Allium

1980 ◽  
Vol 58 (7) ◽  
pp. 773-785 ◽  
Author(s):  
Barry A. Palevitz
Keyword(s):  
Cytochalasin B ◽  
Cell Plate ◽  
Wall Thickening ◽  
Animal Cells ◽  
Host Fungus ◽  
Guard Mother Cells ◽  
Mother Cells ◽  
Chromosome Motion

Cytochalasin B (CB), thought to disaggregate F-actin in animal cells, and phalloidin (Phal), known to stabilize F-actin in vivo and in vitro, have nearly identical effects on cotyledon epidermal cells of Allium cepa. Both drugs rapidly induce cessation of streaming and both, by preventing normal telophase reorientation movement, lead to abnormal division planes in dividing guard mother cells. Neither, however, prevents normal microtubule deposition, wall thickening, and cellulose orientation during guard cell differentiation. Furthermore, both drugs have no effect on spindle formation and anaphase chromosome motion. Examination of Nitella and Chara cells, in which streaming had been stopped by either agent, shows that microfilament cables are still present. With both drugs, the minimum effective concentrations were routinely used (CB, 2 μM; Phal, 100–200 μM). Our results are discussed in terms of the mode of action of these drugs and their possible role in host-fungus interactions. Implications for the mechanisms underlying cell plate alignment, cellulose orientation, and cytoplasmic streaming are discussed.

Establishment of division plane and mitosis in monoplastidic guard mother cells ofSelaginella

1992 ◽  
Vol 23 (2) ◽  
pp. 89-101 ◽  
Author(s):  
Ann L. Cleary ◽  
Roy C. Brown ◽  
Betty E. Lemmon
Keyword(s):  
Division Plane ◽  
Guard Mother Cells ◽  
Mother Cells

Development of the preprophase band from random cytoplasmic microtubules in guard mother cells of Allium cepa L.

Planta ◽  
1989 ◽  
Vol 178 (3) ◽  
pp. 291-296 ◽  
Author(s):  
Y. Mineyuki ◽  
J. Marc ◽  
B. A. Palevitz
Keyword(s):  
Allium Cepa ◽  
Preprophase Band ◽  
Allium Cepa L ◽  
Cytoplasmic Microtubules ◽  
Guard Mother Cells ◽  
Mother Cells

Blue light-induced, intrinsic vacuolar fluorescence in onion guard cells

1979 ◽  
Vol 37 (1) ◽  
pp. 1-10
Author(s):  
E. Zeiger ◽  
P.K. Hepler
Keyword(s):  
Blue Light ◽  
Single Cells ◽  
Broad Band ◽  
Guard Cells ◽  
Emission Peak ◽  
Blue Light Receptor ◽  
Guard Cell Protoplasts ◽  
Guard Mother Cells ◽  
Mother Cells ◽  
Eleven Species

Guard cells of onion irradiated with broad-band blue light display a green intrinsic fluorescence. The fluorescence has been found in eleven species of Allium, but it has not been observed in any other monocot or dicot examined. The fluorescence occurs only in guard cells and is absent in neighbouring epidermal cells. During development it is first apparent in guard mother cells soon after the asymmetric division. Microscopic observation reveals that the fluorescence is associated with the vacuole and examination of vacuoles isolated from guard cell protoplasts suggests that it may be localized on the tonoplast. Microspectrophotometric analysis of single cells reveals an emission peak at around 520 nm. Our results are consistent with the view that this blue light receptor is a flavin or flavoprotein and that it might be related to the blue light-enhanced stomatal opening observed in onion.

Microtubule reorganization accompanying preprophase band formation in guard mother cells ofAvena sativa L.

PROTOPLASMA ◽  
1989 ◽  
Vol 149 (2-3) ◽  
pp. 89-94 ◽  
Author(s):  
J. B. Mullinax ◽  
B. A. Palevitz
Keyword(s):  
Preprophase Band ◽  
Band Formation ◽  
Guard Mother Cells ◽  
Mother Cells

The subcellular organization of stomatal initials in sugarcane leaves: the guard and subsidiary mother cells

1977 ◽  
Vol 55 (22) ◽  
pp. 2801-2809 ◽  
Author(s):  
A. P. Singh
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Close Association ◽  
Preprophase Band ◽  
Central Position ◽  
Guard Mother Cell ◽  
Subcellular Organization ◽  
Guard Mother Cells ◽  
Mother Cells ◽  
Preprophase Bands

The subcellular organization of guard and subsidiary mother cells in sugarcane leaves was examined by electron microscopy. Guard and subsidiary mother cells assume a characteristic shape before mitosis and contain variable numbers of mitochondria, proplastids, dictyosomes, and cisternae of rough endoplasmic reticulum. In guard mother cells, the nucleus occupies a central position, whereas in subsidiary mother cells, the nucleus is located toward one end of the cell, near the guard mother cell. Microtubules are found in both guard and subsidiary mother cells and are either closely grouped to form defined preprophase bands or randomly dispersed between the nucleus and the preprophase bands. Many of the dispersed microtubules occur in close association with the nucleus in both guard and subsidiary mother cells. Possible functions for these preprophase microtubules are discussed in relation to their organization in the preprophase band, their orientation, and their distribution within guard and subsidiary mother cells.

scholarly journals Arabidopsis EGY1 Is Critical for Chloroplast Development in Leaf Epidermal Guard Cells

Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1254
Author(s):  
Alvin Sanjaya ◽  
Ryohsuke Muramatsu ◽  
Shiho Sato ◽  
Mao Suzuki ◽  
Shun Sasaki ◽  
...  
Keyword(s):  
Chloroplast Development ◽  
Fluorescent Proteins ◽  
Guard Cells ◽  
Cell Types ◽  
Mesophyll Cells ◽  
Pavement Cells ◽  
Normal Number ◽  
Chloroplast Formation ◽  
Guard Mother Cells ◽  
Mother Cells

In Arabidopsis thaliana, the Ethylene-dependent Gravitropism-deficient and Yellow-green 1 (EGY1) gene encodes a thylakoid membrane-localized protease involved in chloroplast development in leaf mesophyll cells. Recently, EGY1 was also found to be crucial for the maintenance of grana in mesophyll chloroplasts. To further explore the function of EGY1 in leaf tissues, we examined the phenotype of chloroplasts in the leaf epidermal guard cells and pavement cells of two 40Ar17+ irradiation-derived mutants, Ar50-33-pg1 and egy1-4. Fluorescence microscopy revealed that fully expanded leaves of both egy1 mutants showed severe chlorophyll deficiency in both epidermal cell types. Guard cells in the egy1 mutant exhibited permanent defects in chloroplast formation during leaf expansion. Labeling of plastids with CaMV35S or Protodermal Factor1 (PDF1) promoter-driven stroma-targeted fluorescent proteins revealed that egy1 guard cells contained the normal number of plastids, but with moderately reduced size, compared with wild-type guard cells. Transmission electron microscopy further revealed that the development of thylakoids was impaired in the plastids of egy1 mutant guard mother cells, guard cells, and pavement cells. Collectively, these observations demonstrate that EGY1 is involved in chloroplast formation in the leaf epidermis and is particularly critical for chloroplast differentiation in guard cells.

scholarly journals Metabolic inhibitors block anaphase A in vivo.

1986 ◽  
Vol 102 (6) ◽  
pp. 1995-2005 ◽  
Author(s):  
P K Hepler ◽  
B A Palevitz
Keyword(s):  
Metabolic Inhibitors ◽  
Pole Motion ◽  
Carbonyl Cyanide ◽  
Transport Inhibitors ◽  
Spindle Microtubules ◽  
Guard Mother Cells ◽  
Mother Cells ◽  
Anaphase B ◽  
Chromosome Motion

Anaphase in dividing guard mother cells of Allium cepa and stamen hair cells of Tradescantia virginiana consists almost entirely of chromosome-to-pole motion, or anaphase A. Little or no separation of the poles (anaphase B) occurs. Anaphase is reversibly blocked at any point by azide or dinitrophenol, with chromosome motion ceasing 1-10 min after application of the drugs. Motion can be stopped and restarted several times in the same cell. Prometaphase, metaphase, and cytoplasmic streaming are also arrested. Carbonyl cyanide m-chlorophenyl hydrazone also stops anaphase, but its effects are not reversible. Whereas the spindle collapses in the presence of colchicine, the chromosomes seem to "freeze" in place when cells are exposed to respiratory inhibitors. Electron microscope examination of dividing guard mother cells fixed during azide and dinitrophenol treatment reveals that spindle microtubules are still present. Our results show that chromosome-to-pole motion in these cells is sensitive to proton ionophores and electron transport inhibitors. They therefore disagree with recent reports that anaphase A does not require a continuous supply of energy. It is possible, however, that anaphase does not directly use ATP but instead depends on the energy of chemical and/or electrical gradients generated by cellular membranes.

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