The spectral sensitivity of Hydra carnea L. Agassiz (1850)

1970 ◽  
Vol 48 (1) ◽  
pp. 63-68 ◽  
Author(s):  
Virginia L. Ellis
Keyword(s):  
Growth Rate ◽  
Reaction Time ◽  
Spectral Sensitivity ◽  
White Light ◽  
Red Light ◽  
Action Spectrum ◽  
Green Light ◽  
Reaction Times ◽  
Light Stimuli ◽  
Hydra Carnea

The spectral sensitivity of Hydra carnea was investigated by growth rate and action spectrum studies. The rate of asexual growth was measured over a 40-day period for animals cultured under white, blue, green, and red lights of equal intensity. The growth rate was greatest under red light and slowest under blue; the rate under white light was similar to that under green light. The action spectrum, measured as the reaction times to light stimuli of various wavelengths, varied according to the light under which the animals were cultured. For H. carnea that had been cultured in the dark, the reaction time was shortest at 650 nm and longest at 450 nm when lights of equal intensity were used. This differs from the results of an earlier study with H. pirardi, which showed maximum sensitivity to blue light. Animals cultured under blue, green, and red lights showed a decreased sensitivity, indicated by an increased reaction time, to the light under which they were cultured as compared to animals cultured in the dark.

Light-evoked contraction of red absorbing cones in the Xenopus retina is maximally sensitive to green light

1992 ◽  
Vol 8 (3) ◽  
pp. 243-249 ◽  
Author(s):  
Joseph C. Besharse ◽  
Paul Witkovsky
Keyword(s):  
Xenopus Laevis ◽  
Spectral Sensitivity ◽  
Red Light ◽  
Green Light ◽  
Sensitivity Function ◽  
Direct Mechanism ◽  
Sensitivity Experiments ◽  
Light Stimuli ◽  
The Difference ◽  
Spectral Sensitivity Function

AbstractTo test the hypothesis that light-evoked cone contraction in eye cups from Xenopus laevis is controlled through a direct mechanism initiated by the cone's own photopigment, we conducted spectral-sensitivity experiments. We estimate that initiation of contraction of red absorbing cones (611 nm) is 1.5 log units more sensitive to green (533 nm) than red (650 nm) light stimuli. The difference is comparable to that predicted from the spectral-sensitivity function of the green absorbing, principal rod (523 nm). Furthermore, 480-nm and 580-nm stimuli which are absorbed nearly equally by the principal rod have indistinguishable effects on cone contraction. We also found that light blockade of nighttime cone elongation is much more sensitive to green than to red light stimuli. Our observations are inconsistent with the hypothesis tested, and suggest that light-regulated cone motility is controlled through an indirect mechanism initiated primarily by the green absorbing, principal rod.

Underwater light climate and the growth and pigmentation of planktonic blue-green algae (Cyanobacteria) II. The influence of light quality

1986 ◽  
Vol 227 (1248) ◽  
pp. 381-393 ◽  
Keyword(s):  
Growth Rate ◽  
Flux Density ◽  
Green Algae ◽  
White Light ◽  
Light Quality ◽  
Red Light ◽  
Green Light ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Blue Green Algae

The influence of light quality on the growth and chlorophyll and phycobiliprotein composition of eight strains of planktonic blue-green algae has been investigated. Growth rate in chromatic (red, green, blue) light (12 μE m -2 s -1 ) (1 μE = 6 × 10 17 photons) is a general function of the light absorption capacity of the cell. In all strains examined growth rate is enhanced in red light, and in Oscillatoria redekei and Gloeotrichia echinulata CC1 it exceeds the maximum growth rate possible in white light of a higher photon flux density under otherwise similar experimental conditions. In green light the growth rate of six phycocyanin-rich strains is approximately 60–75% of that in white light (12 μE m -2 s -1 ), but growth rate is enhanced in O. agardhii 7821 and G. echinulata CC1, which synthesize the green-light-absorbing phycobiliprotein, phycoerythrin. With the exception of these two phycoerythrin-producing strains, incubation in blue light results in a pronounced reduction in growth rate, which in the majority of strains is associated with a specific decline in cell chlorophyll concentrations. In all strains cell chlorophyll and phycobiliprotein content is similar in both white and green light. Associated with the enhancement of growth rate in red light there is a general decline in cell pigment concentrations. An increase in the cell chlorophyll: phycobiliprotein ratio also occurs in a number of strains in red light. This qualitative variation in pigmentation occurs where growth rate is at or near its maximum rate and in Gloeotrichia echinulata CC1 is the result of a specific reduction in the rate of phycoerythrin synthesis. In contrast to other blue-green algae capable of chromatic adaptation, the modulation of phycoerythrin synthesis in this strain is influenced considerably by the photon flux density of red light.

Presence of Both Hemidiscoidal and Hemiellipsoidal Phycobilisomes in a Phormidium Species (Cyanobacteria)

1993 ◽  
Vol 48 (1-2) ◽  
pp. 28-34 ◽  
Author(s):  
Martin Westermann ◽  
Wolfgang Reuter ◽  
Christine Schimek ◽  
Werner Wehrmeyer
Keyword(s):  
White Light ◽  
Red Light ◽  
Green Light ◽  
Pigment Ratios ◽  
Light Cells ◽  
Sedimentation Value ◽  
In Cells

Hemidiscoidal and hemiellipsoidal phycobilisomes have been determined in cells of the complementary chromatically adapting cyanobacterium Phormidium sp. C86 . They could be isolated from red and green light-adapted cells, respectively. Hemidiscoidal red light phycobilisomes show molar pigment ratios of allophycocyanin: phycocyanin of 1:4.5 with phycoerythrin lacking. Hemiellipsoidal phycobilisomes induced by green light present allophycocyanin: phycocyanin: phycoerythrin ratios of 1:1:6.8. The differences between the two phycobilisome types could additionally be demonstrated by their ultrastructure and sedimentation values. Isolated red light phycobilisomes have six rods, show dimensions of 70×30×15nm and a sedimentation value of 66 S whereas green light phycobilisomes are nearly twice larger. They contain ten rods and present dimensions of 70×40×25nm and a sedimentation value of 98 S. The number of phycobilisomes in red light cells is almost twice as large as in green light cells. There is evidence that cells grown under white light contain both types as well as “intermediate” forms.

Relationships of Auditory and Visual Reaction Times to Reading Achievement

1968 ◽  
Vol 27 (2) ◽  
pp. 447-450 ◽  
Author(s):  
Walter A. Busby ◽  
Donald E. Hurd
Keyword(s):  
Reaction Time ◽  
Reading Achievement ◽  
Single Channel ◽  
Visual Stimuli ◽  
Green Light ◽  
Reaction Times ◽  
Perceptual Field ◽  
Visual Channel ◽  
Visual Reaction ◽  
Low Tone

To determine the relationship between reading achievement and the reaction time of an individual responding to auditory and visual stimuli present in his perceptual field Ss were selected at random from Grades 2, 4 and 6. S lifted his finger from a key as rapidly as possible at the onset of any one of four stimuli (red or green light, high or low tone). Shifting reaction time was not independent of reaction time in either the auditory or visual channel. Hence, the possibility that relative perceptual difficulties could exist in shifting behavior while no defect existed in either single channel was not supported. Perception defined as the reaction time of an individual responding to auditory and visual stimuli was not significantly related to reading achievement.

scholarly journals The influence of light quality on the shoot proliferation and rooting of Gerbera jamesonii in vitro

2013 ◽  
Vol 48 (2) ◽  
pp. 105-111 ◽  
Author(s):  
Eleonora Gabryszewska ◽  
Ryszard Rudnicki
Keyword(s):  
White Light ◽  
Light Quality ◽  
Red Light ◽  
Green Light ◽  
Shoot Proliferation ◽  
Gerbera Jamesonii ◽  
Fresh Weight ◽  
Axillary Shoots ◽  
The Media

The effect of white, blue, green, red and UV + white light on the growth and development of shoots and roots of Gerbera jamesonii cv. Queen Rebecca in relation to the presence of kinetin or IAA were investigated. The highest number of axillary shoots was obtained in red and green light on the medium with 5 mg l<sup>-1</sup> kinetin. Also, green and red light markedly increased the number of leaves developed on the plantlets on the medium supplemented with kinetin. Light quality and IAA added to culture medium variously affected the development of root system: roots were regenerated under all light treatments, higher root number was recorded under red light when 5 mg l<sup>-1</sup> IAA was added to the media, the shortest roots were found in red light on the medium supplemented with IAA. The greatest fresh weight of shoots was found under white light on the medium with kinetin. Red light markedly decreased shoot fresh weight on hormone-free medium. Blue and white light caused increase in fresh weight of roots.

scholarly journals Transcriptomic and Metabolomic Profiling Reveals the Effect of LED Light Quality on Fruit Ripening and Anthocyanin Accumulation in Cabernet Sauvignon Grape

2021 ◽  
Vol 8 ◽  
Author(s):  
Peian Zhang ◽  
Suwen Lu ◽  
Zhongjie Liu ◽  
Ting Zheng ◽  
Tianyu Dong ◽  
...  
Keyword(s):  
Blue Light ◽  
White Light ◽  
Plant Traits ◽  
Soluble Sugars ◽  
Red Light ◽  
Green Light ◽  
Grape Berries ◽  
Light Spectra ◽  
Metabolomic Profiling ◽  
Highly Expressed Genes

Different light qualities have various impacts on the formation of fruit quality. The present study explored the influence of different visible light spectra (red, green, blue, and white) on the formation of quality traits and their metabolic pathways in grape berries. We found that blue light and red light had different effects on the berries. Compared with white light, blue light significantly increased the anthocyanins (malvidin-3-O-glucoside and peonidin-3-O-glucoside), volatile substances (alcohols and phenols), and soluble sugars (glucose and fructose), reduced the organic acids (citric acid and malic acid), whereas red light achieved the opposite effect. Transcriptomics and metabolomics analyses revealed that 2707, 2547, 2145, and 2583 differentially expressed genes (DEGs) and (221, 19), (254, 22), (189, 17), and (234, 80) significantly changed metabolites (SCMs) were filtered in the dark vs. blue light, green light, red light, and white light, respectively. According to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, most of the DEGs identified were involved in photosynthesis and biosynthesis of flavonoids and flavonols. Using weighted gene co-expression network analysis (WGCNA) of 23410 highly expressed genes, two modules significantly related to anthocyanins and soluble sugars were screened out. The anthocyanins accumulation is significantly associated with increased expression of transcription factors (VvHY5, VvMYB90, VvMYB86) and anthocyanin structural genes (VvC4H, Vv4CL, VvCHS3, VvCHI1, VvCHI2, VvDFR), while significantly negatively correlated with VvPIF4. VvISA1, VvISA2, VvAMY1, VvCWINV, VvβGLU12, and VvFK12 were all related to starch and sucrose metabolism. These findings help elucidate the characteristics of different light qualities on the formation of plant traits and can inform the use of supplemental light in the field and after harvest to improve the overall quality of fruit.

Enhanced Microalgal Lipid Production in Internally Illuminated Airlift Photobioreactor

2019 ◽  
Vol 53 (2) ◽  
pp. 38-45
Author(s):  
Irem Deniz ◽  
Zeliha Demirel ◽  
Esra Imamoglu ◽  
Meltem Conk Dalay
Keyword(s):  
Fatty Acids ◽  
Growth Rate ◽  
Blue Light ◽  
Lipid Content ◽  
White Light ◽  
Lipid Production ◽  
Red Light ◽  
Light Spectrum ◽  
Light Supply ◽  
Total Fatty Acids

AbstractInternal illumination systems are being considered for use as an alternative light supply technique in microalgal products. The main goal of the study was to analyze the roles of different light wavelengths in internally illuminated airlift photobioreactors (PBRs) providing the light energy in an efficient way for the biomass production, lipid yield, and fatty acid composition of Amphora capitellata. The maximum chlorophyll-a concentration per unit biomass (2.62 ± 0.16 mg L−1) was obtained under red light, which was only 14% higher than under blue light in internally illuminated airlift PBR, whereas low chlorophyll-a content was found under white light. Maximum specific growth rate of 0.317 day−1, which corresponded to a doubling time of 2.185 days, was obtained under red light for A. capitellata. It was found that lipid content increased with decreasing growth rate for A. capitellata. Palmitic acid (C16:0) and palmitoleic acid (C16:1) were the principal fatty acids accounting for between 31%‐33% and 31%‐32% of total fatty acids, respectively. It is important to underline that red and blue light spectrum ranges contribute to improved biomass growth, whereas white light has the potential to support lipid content of diatoms.

scholarly journals Green Light Drives Leaf Photosynthesis More Efficiently than Red Light in Strong White Light: Revisiting the Enigmatic Question of Why Leaves are Green

2009 ◽  
Vol 50 (4) ◽  
pp. 684-697 ◽  
Author(s):  
Ichiro Terashima ◽  
Takashi Fujita ◽  
Takeshi Inoue ◽  
Wah Soon Chow ◽  
Riichi Oguchi
Keyword(s):  
White Light ◽  
Red Light ◽  
Green Light ◽  
Leaf Photosynthesis

scholarly journals Dual and Multi-Emission Hybrid Micelles Realized through Coordination-Driven Self-Assembly

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 440
Author(s):  
Youxiong Zheng ◽  
Yan Tang ◽  
Jianwei Yu ◽  
Lan Xie ◽  
Huiyou Dong ◽  
...  
Keyword(s):  
Blue Light ◽  
White Light ◽  
Self Assembly ◽  
Light Emission ◽  
Raft Polymerization ◽  
Red Light ◽  
Green Light ◽  
Assembly Process ◽  
Blue Light Emission ◽  
Dual Emission

Building novel functional nanomaterials with a polymer is one of the most dynamic research fields at present. Here, three amphiphilic block copolymers of 8-hydroxyquinoline derivative motifs (MQ) with excellent coordination function were synthesized by Reversible Addition-Fragmentation Chain Transfer Polymerization (RAFT) polymerization. The coordination micelles were prepared through the self-assembly process, which the MQ motifs were dispersed in the hydrophobic polystyrene (PSt) blocks and hydrophilic Poly(N-isopropylacrylamide (PNIPAM)) blocks, respectively. The dual-emission micelles including the intrinsic red light emission of quantum dots (QDs) and the coordination green light emission of Zn2+-MQ complexes were built by introducing the CdSe/ZnS and CdTe/ZnS QDs in the core and shell precisely in the coordination micelles through the coordination-driven self-assembly process. Furthermore, based on the principle of three primary colors that produce white light emission, vinyl carbazole units (Polyvinyl Carbazole, PVK) with blue light emission were introduced into the hydrophilic PNIPAM blocks to construct the white light micelles that possess special multi-emission properties in which the intrinsic red light emission of QDs, the coordination green light of Zn2+-MQ complexes, and the blue light emission of PVK were synergized. The dual and multi-emission hybrid micelles have great application prospects in ratiometric fluorescent probes and biomarkers.

scholarly journals Effect of colour of light on the opening of inflorescence buds and post-harvest longevity of pot chrysanthemums (Chrysanthemum × grandiflorum (Ramat.) Kitam)

2012 ◽  
Vol 64 (3) ◽  
pp. 13-18 ◽  
Author(s):  
Marek Jerzy ◽  
Piotr Zakrzewski ◽  
Anita Schroeter-Zakrzewska
Keyword(s):  
Blue Light ◽  
Significant Influence ◽  
White Light ◽  
Red Light ◽  
Green Light ◽  
Fluorescent Light ◽  
Yellow Light ◽  
Post Harvest ◽  
Growth Room

The pot cultivar of <i>Chrysanthemum</i> × <i>grandiflorum</i> 'Leticia Time Yellow' was cultivated and stored in a growth room under fluorescent light of white, blue, green, yellow and red colour. Quantum irradiance was 30 μmol · m<sup>-2</sup> × s<sup>-1</sup>. The colour of light exerted a significant influence on the opening of closed inflorescence buds and on post-harvest longevity of pot chrysanthemums grown earlier in an unheated plastic tunnel. Under florescent lamps emitting blue light at a wavelength of 400-580 nm, inflorescence buds opened and coloured the earliest. The number of developed flower heads was the greatest under blue and white light. Flower heads developing in blue light were bigger than flower heads developing in white and green light. In red light at a wavelength of 600-700 nm, plants flowered latest and they produced the smallest flower heads. Post-harvest longevity was preserved longest in chrysanthemums kept under blue, white and green light. In red and yellow light, the flowers were overblown earliest.

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