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.

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 Guard cells control hypocotyl elongation through HXK1, HY5, and PIF4

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Gilor Kelly ◽  
Danja Brandsma ◽  
Aiman Egbaria ◽  
Ofer Stein ◽  
Adi Doron-Faigenboim ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Blue Light ◽  
Opposite Effect ◽  
Red Light ◽  
Guard Cells ◽  
Cell Types ◽  
Hypocotyl Elongation ◽  
Sugar Production ◽  
Effect Of Light

AbstractThe hypocotyls of germinating seedlings elongate in a search for light to enable autotrophic sugar production. Upon exposure to light, photoreceptors that are activated by blue and red light halt elongation by preventing the degradation of the hypocotyl-elongation inhibitor HY5 and by inhibiting the activity of the elongation-promoting transcription factors PIFs. The question of how sugar affects hypocotyl elongation and which cell types stimulate and stop that elongation remains unresolved. We found that overexpression of a sugar sensor, Arabidopsis hexokinase 1 (HXK1), in guard cells promotes hypocotyl elongation under white and blue light through PIF4. Furthermore, expression of PIF4 in guard cells is sufficient to promote hypocotyl elongation in the light, while expression of HY5 in guard cells is sufficient to inhibit the elongation of the hy5 mutant and the elongation stimulated by HXK1. HY5 exits the guard cells and inhibits hypocotyl elongation, but is degraded in the dark. We also show that the inhibition of hypocotyl elongation by guard cells’ HY5 involves auto-activation of HY5 expression in other tissues. It appears that guard cells are capable of coordinating hypocotyl elongation and that sugar and HXK1 have the opposite effect of light on hypocotyl elongation, converging at PIF4.

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

Light-dependent suppression of COP1 multimeric complex formation is determined by the blue-light receptor FKF1 in Arabidopsis

2019 ◽  
Vol 508 (1) ◽  
pp. 191-197 ◽  
Author(s):  
Byoung-Doo Lee ◽  
Joon-Yung Cha ◽  
Mi Ri Kim ◽  
Gyeong-Im Shin ◽  
Nam-Chon Paek ◽  
...  
Keyword(s):  
Complex Formation ◽  
Blue Light ◽  
Blue Light Receptor ◽  
Multimeric Complex ◽  
Light Receptor

TETRAPLOID TARAXACUM KOK-SAGHYZ: I. CHARACTERS OF THE LEAVES AND INFLORESCENCES IN THE PARENTAL COLCHICINE-INDUCED GENERATION

1945 ◽  
Vol 23c (4) ◽  
pp. 131-143 ◽  
Author(s):  
M. W. Bannan
Keyword(s):  
Guard Cells ◽  
Stages Of Development ◽  
Pollen Mother Cells ◽  
Mother Cells

Seedlings at different stages of development were treated with colchicine. Successive selections on the aspect of the seedlings soon after treatment, on size of the guard cells at the time of repotting, and finally, after overwintering, on counts of the chromosomes in the pollen mother cells yielded a few hundred plants with tetraploid crowns. These plants bore fewer, broader leaves and fewer, bigger inflorescences with larger achenes than did selected large-celled diploids given the same treatment, but in general the plants were no bigger. A few of the tetraploids were self-fertile (if not apomictic) early in the spring, but later all tested plants proved self-sterile.

Effects of Charge Compensators on Structure and Luminescent Properties of Microwave Synthesized CaMoO4:Eu3+ Red Phosphors

2017 ◽  
Vol 727 ◽  
pp. 592-597
Author(s):  
Ying Han ◽  
Zhi Lin Li ◽  
Wan Zhang ◽  
Yan Jie Yin ◽  
Yan Mei Li ◽  
...  
Keyword(s):  
Broad Band ◽  
Luminescent Properties ◽  
Emission Peak ◽  
Luminous Intensity ◽  
Main Peak ◽  
Doping Amount ◽  
X Ray ◽  
Red Phosphors ◽  
Charge Compensator ◽  
Pure Phase

Red phosphors CaMoO4:Eu3+ were synthesized by microwave method with MnO2 as microwave absorbent. The phase structure and luminescent properties of the as-synthesized phosphors were investigated by X-ray powder diffraction and Fluorescence spectrophotometer. The results show that when the reaction time was 40 min, microwave power was medium-high fire (~560 W), we got the tetragonal CaMoO4:Eu3+ pure phase. The excitation spectrum of CaMoO4:Eu3+ was composed by a broad band between 200 nm and 350 nm and a series of peaks from 350 nm to 500 nm. The main peak was at 305 nm. The emission spectrum was composed of a series of peaks in the range of 550~750 nm and the main peak was at 617 nm due to the 5D0→7F2 transition of Eu3+. Doping charge compensator Li+, Na+ or K+ could improve the luminous intensity of the sample. When the doping amount of Li+, Na+ or K+ were 8 mol%, the luminous intensity of the sample reached the maximum. The intensity of the emission peak at 617 nm was 4.04, 3.42, 3.48 times of sample without doping charge compensator.

scholarly journals A Simple and Low-Cost Strategy to Improve Conidial Yield and Stress Resistance of Trichoderma guizhouense through Optimizing Illumination Conditions

2022 ◽  
Vol 8 (1) ◽  
pp. 50
Author(s):  
Yifan Li ◽  
Xiya Meng ◽  
Degang Guo ◽  
Jia Gao ◽  
Qiwei Huang ◽  
...  
Keyword(s):  
Blue Light ◽  
Stress Responses ◽  
Stress Resistance ◽  
Low Cost ◽  
Hog Pathway ◽  
Precise Control ◽  
Blue Light Receptor ◽  
Expression Of Genes ◽  
Low Cost Strategy ◽  
Stress Related Genes

Light is perceived by photoreceptors in fungi and further integrated into the stress-activated MAPK HOG pathway, and thereby potentially activates the expression of genes for stress responses. This indicates that the precise control of light conditions can likely improve the conidial yield and stress resistance to guarantee the low cost and long shelf life of Trichoderma-based biocontrol agents and biofertilizers. In this study, effects of wavelengths and intensities of light on conidial yield and stress tolerance to osmotic, oxidative and pH stresses in Trichoderma guizhouense were investigated. We found that 2 μmol photons/(m2 × s) of blue light increased the conidial yield more than 1000 folds as compared to dark condition and simultaneously enhanced conidial stress resistance. The enhanced conidial stress resistance is probably due to the upregulated stress-related genes in blue light, which is under the control of the blue light receptor BLR1 and the MAP kinase HOG1.

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.

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