Blue and red light effects on stomatal oscillations

The response of stomata to red and blue light was investigated using small fibre optics (66µm diameter) to control light levels on a single pair of guard cells without affecting the surrounding tissue. Low intensity red light (50µmolm–2s–1) applied to the entire leaf caused stomata to oscillate continuously for several hours with no apparent decrease in amplitude with time. Adding low intensity blue light (50µmolm–2s–1) caused stomata to stop oscillating, but oscillations resumed when the blue light was removed. Adding the same intensity of red light to an oscillating leaf changed the amplitude of the oscillations but did not stop them. When blue light was added to a single guard cell pair (using a fibre optic) in a red-light-illuminated leaf, the stoma formed by that pair stopped oscillating, but adjacent stomata did not. Red light added to a single guard cell pair did not stop oscillations. Finally, blue light applied through a fibre optic to areas of leaf without stomata caused proximal stomata to stop oscillating, but distal stomata continued to oscillate. The data suggest that blue light affects stomata via direct effects on guard cells as well as by indirect effects on other cells in the leaf.

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

Communications Biology ◽

10.1038/s42003-021-02283-y ◽

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.

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

Canadian Journal of Botany ◽

10.1139/b75-001 ◽

1975 ◽

Vol 53 (1) ◽

pp. 1-7 ◽

Cited By ~ 46

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.

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Blue light response of stomata with starch-containing (Vicia faba) and starch-deficient (Allium cepa) guard cells under background illumination with red light

Plant Science Letters ◽

10.1016/0304-4211(81)90131-0 ◽

1981 ◽

Vol 22 (2) ◽

pp. 103-108 ◽

Cited By ~ 19

Author(s):

Teruo Ogawa

Keyword(s):

Vicia Faba ◽

Blue Light ◽

Allium Cepa ◽

Red Light ◽

Light Response ◽

Guard Cells ◽

Background Illumination ◽

Blue Light Response

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Effect of blue and red radiation on cycling stomata of bean.

Netherlands Journal of Agricultural Science ◽

10.18174/njas.v21i2.17255 ◽

1973 ◽

Vol 21 (2) ◽

pp. 117-123

Author(s):

P.A.M. Hopmans

Keyword(s):

Blue Light ◽

Red Light ◽

Guard Cells ◽

Radiant Flux ◽

Stomatal Behaviour ◽

Blue Radiation ◽

Quantum Flux ◽

Permeability For Water ◽

Red Radiation ◽

Blue And Red Radiation

Differences in the effect of blue and red radiation of low radiant flux density on sustained stomatal cycling were studied in Phaseolus vulgaris cv. Vroege Wagenaar. Stomatal behaviour in a constant environment was observed indirectly by recording the differences between leaf and air temperature. In radiation with equal radiant flux densities of 1.75 W/m2 and with equal estimated absorbed quantum flux densities of 0.73 nE/cm2 s of both colours, cycling was more rapid and peak-to-trough differences were smaller in red than in blue radiation. Blue radiation from below caused more rapid cycling with larger peak-to-trough differences than radiation from above. In red radiation the direction of radiation had a much smaller influence on period and peak-to-trough difference. To explain these qualitatively different effects of both colours on cycling stomata, the hypothesis is proposed that blue light increases the osmotic pressure in the guard cells more effectively than red light. In blue light the permeability for water transport of the guard cell membranes is lower than in red light. (Abstract retrieved from CAB Abstracts by CABI’s permission)

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Fast Fluorescence Quenching from Isolated Guard Cell Chloroplasts of Vicia faba Is Induced by Blue Light and Not by Red Light

PLANT PHYSIOLOGY ◽

10.1104/pp.100.3.1562 ◽

1992 ◽

Vol 100 (3) ◽

pp. 1562-1566 ◽

Cited By ~ 6

Author(s):

Alaka Srivastava ◽

Eduardo Zeiger

Keyword(s):

Fluorescence Quenching ◽

Vicia Faba ◽

Blue Light ◽

Guard Cell ◽

Red Light ◽

Guard Cell Chloroplasts

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Phototropin 1 and dim-blue light modulate the red light de-etiolation response

Plant Signaling & Behavior ◽

10.4161/15592324.2014.976158 ◽

2014 ◽

Vol 9 (11) ◽

pp. e976158

Author(s):

Yihai Wang ◽

Kevin M Folta

Keyword(s):

Blue Light ◽

Red Light

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Single Wavelengths of LED Light Supplement Promote the Biosynthesis of Major Cyclic Monoterpenes in Japanese Mint

Plants ◽

10.3390/plants10071420 ◽

2021 ◽

Vol 10 (7) ◽

pp. 1420

Author(s):

Takahiro Ueda ◽

Miki Murata ◽

Ken Yokawa

Keyword(s):

Blue Light ◽

Solid Phase ◽

Glandular Trichomes ◽

Red Light ◽

Glandular Trichome ◽

Pulse Amplitude ◽

Light Treatment ◽

Led Light ◽

Trichome Formation ◽

Japanese Mint

Environmental light conditions influence the biosynthesis of monoterpenes in the mint plant. Cyclic terpenes, such as menthol, menthone, pulegone, and menthofuran, are major odor components synthesized in mint leaves. However, it is unclear how light for cultivation affects the contents of these compounds. Artificial lighting using light-emitting diodes (LEDs) for plant cultivation has the advantage of preferential wavelength control. Here, we monitored monoterpene contents in hydroponically cultivated Japanese mint leaves under blue, red, or far-red wavelengths of LED light supplements. Volatile cyclic monoterpenes, pulegone, menthone, menthol, and menthofuran were quantified using the head-space solid phase microextraction method. As a result, all light wavelengths promoted the biosynthesis of the compounds. Remarkably, two weeks of blue-light supplement increased all compounds: pulegone (362% increase compared to the control), menthofuran (285%), menthone (223%), and menthol (389%). Red light slightly promoted pulegone (256%), menthofuran (178%), and menthol (197%). Interestingly, the accumulation of menthone (229%) or menthofuran (339%) was observed with far-red light treatment. The quantification of glandular trichomes density revealed that no increase under light supplement was confirmed. Blue light treatment even suppressed the glandular trichome formation. No promotion of photosynthesis was observed by pulse-amplitude-modulation (PAM) fluorometry. The present result indicates that light supplements directly promoted the biosynthetic pathways of cyclic monoterpenes.

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The Preferences of Different Cultivars of Lettuce Seedlings (Lactuca sativa L.) for the Spectral Composition of Light

Agronomy ◽

10.3390/agronomy11061211 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1211

Author(s):

Barbara Frąszczak ◽

Monika Kula-Maximenko

Keyword(s):

Chlorophyll Content ◽

Blue Light ◽

White Light ◽

Leaf Shape ◽

Red Light ◽

Spectral Composition ◽

Fresh Weight ◽

Light Spectrum ◽

Dark Green ◽

Relative Chlorophyll Content

The spectrum of light significantly influences the growth of plants cultivated in closed systems. Five lettuce cultivars with different leaf colours were grown under white light (W, 170 μmol m−2 s−1) and under white light with the addition of red (W + R) or blue light (W + B) (230 μmol m−2 s−1). The plants were grown until they reached the seedling phase (30 days). Each cultivar reacted differently to the light spectrum applied. The red-leaved cultivar exhibited the strongest plasticity in response to the spectrum. The blue light stimulated the growth of the leaf surface in all the plants. The red light negatively influenced the length of leaves in the cultivars, but it positively affected their number in red and dark-green lettuce. It also increased the relative chlorophyll content and fresh weight gain in the cultivars containing anthocyanins. When the cultivars were grown under white light, they had longer leaves and higher value of the leaf shape index. The light-green cultivars had a greater fresh weight. Both the addition of blue and red light significantly increased the relative chlorophyll content in the dark-green cultivar. The spectrum enhanced with blue light had positive influence on most of the parameters under analysis in butter lettuce cultivars. These cultivars were also characterised by the highest absorbance of blue light.

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