The Effect of Light Quality on the Germination of Eight Species From Sandy Habitats in Western Australia.

1993 ◽  
Vol 41 (3) ◽  
pp. 321 ◽  
Author(s):  
DT Bell
Keyword(s):  
Western Australia ◽  
Light Quality ◽  
Red Light ◽  
Monochromatic Light ◽  
Coastal Dunes ◽  
High Energy ◽  
Germination Percentage ◽  
Light Conditions ◽  
Light Inhibition ◽  
Effect Of Light

The impacts of darkness and a range of monochromatic light conditions on germination was documented for eight native and naturalized species growing in sandy habitats in Western Australia. Four lake-margin species, Juncus articulatus, J. microcephalus, J. pallidus and Isolepis prolifera, germinated under red (c. 520-640 nm) light, but remained dormant in the dark or when illuminated with far-red (720 nm) or blue (430-490 nm) light. Sunlight-stimulated germination could be beneficial to these very small seeded species, which may not have sufficient reserves for seedlings to establish following deep burial. Oenothera stricta, a short-lived ruderal species, was also stimulated by red light, a response possibly related to germination following disturbance of overlying vegetation. Trachyandra divaricata, a dune inhabiting species, was inhibited by red light. Inhibition by the wavelengths of light dominant in full sunlight was thought to be a response beneficial to species of blowing sand habitats where germination on the dry surface could prove detrimental. Oenothera drummorndii , also a species of coastal dunes was inhibited under high energy light (430-490 nm) but showed no percentage gemination differences in light of wavelengths between 520 and 720 nm and under dark conditions. Asphodelus fistulosus, a species of similar life-fonn characteristics to Trachyarndra divaricata, showed no effect on germination percentage of varying light quality.

Factors controlling seed dormancy and germination response of Brachypodium hybridum growing in the hot arid mountains of the Arabian Desert

Botany ◽  
2019 ◽  
Vol 97 (7) ◽  
pp. 371-379 ◽  
Author(s):  
Masarra Elgabra ◽  
Ali El-Keblawy ◽  
Kareem A. Mosa ◽  
Sameh Soliman
Keyword(s):  
Seed Dormancy ◽  
Light Quality ◽  
Genetic Model ◽  
Germination Rate ◽  
Red Light ◽  
Germination Percentage ◽  
Light Conditions ◽  
One Year ◽  
Native And Introduced Ranges ◽  
Seed Dormancy And Germination

Seed dormancy and germination have been studied in the genetic model Brachypodium species complex in cooler, moist higher latitudes. Studying environmental factors in arid mountains affecting dormancy and germination in Brachypodium complex could determine the factors controlling these processes. This study assesses the impacts of temperature during seed maturation, seed after-ripening, drought, photoperiod, and thermoperiod on final germination and germination rate index of B. hybridum in the Arabian Desert. Seeds were germinated under dark or light conditions and under different ratios of red:far-red light, with three diurnal thermoperiods. The final germination percentage was significantly greater at 15/25 °C and 20/30 °C than at 25/35 °C and in light rather than in darkness. Seeds that reached maturity at 15/25 °C attained greater germination rates and faster germination than those that reached maturity at 20/30 °C. One-year after-ripening enhanced the final germination percentage and reduced photoperiod requirements. Light quality did not affect final germination percentage. The seeds tolerated drought of up to –0.8 MPa polyethylene glycol. The tolerance of B. hybridum seeds produced at higher thermoperiods to moderate levels of osmotic stress and their higher dormancy indicate that this species has the potential to survive the projected global warming in its native and introduced ranges.

scholarly journals (402) Effect of Light Quality on Growth and Essential Oil Composition in Rosemary

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1062C-1062
Author(s):  
Giuliana Mulas ◽  
Lyle E. Craker
Keyword(s):  
Essential Oil ◽  
Light Quality ◽  
Biomass Yield ◽  
Red Light ◽  
Plant Morphology ◽  
Essential Oil Composition ◽  
Light Conditions ◽  
Oil Composition ◽  
Number Of Leaves ◽  
Effect Of Light

Variation in light quality is known to modify plant morphology, growth, and chemical constituency in plants. In the present study, the effect of light quality on growth and essential oil composition in rosemary (Rosmarinus officinalis L.) was investigated by comparing plants receiving supplemental red (660 nm) and far-red (730 nm) with each other and with control plants not receiving supplemental light. Except for the supplemental light treatments, all plants were grown under natural light conditions in a greenhouse and received full daylight, averaging 9.23 h/day during the study. The red and far-red light treatments, given as day extensions, started daily 15 min before sunset and continued for 4 h each evening for 4 weeks. No significant differences were observed in biomass yield from the different light treatments, but far-red light caused elongation of internodes and a reduction in the number of leaves in comparison with control and red-light treated plants. Essential oil production was highest in plants grown under far-red light treatments.

scholarly journals Interactive Effects of Light Quality and Temperature on Arabidopsis Growth and Immunity

2020 ◽  
Vol 61 (5) ◽  
pp. 933-941
Author(s):  
Xiaoying Liu ◽  
Chunmei Xue ◽  
Le Kong ◽  
Ruining Li ◽  
Zhigang Xu ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Blue Light ◽  
Light Quality ◽  
Red Light ◽  
Complex Interaction ◽  
Hypocotyl Elongation ◽  
Interactive Effects ◽  
Phytochrome B ◽  
Light Conditions ◽  
Effects Of Temperature

Abstract We report here the interactive effects of three light qualities (white, red and blue) and three growth temperatures (16�C, 22�C and 28�C) on rosette growth, hypocotyl elongation and disease resistance in Arabidopsis thaliana. While an increase in temperature promotes hypocotyl elongation irrespective of light quality, the effects of temperature on rosette growth and disease resistance are dependent on light quality. Maximum rosette growth rate under white, red and blue light are observed at 28�C, 16�C and 22�C, respectively. The highest disease resistance is observed at 16�C under all three light conditions, but the highest susceptibility is observed at 28�C for white light and 22�C for red and blue light. Interestingly, rosette growth is inhibited by phytochrome B (PHYB) under blue light at 28�C and by cryptochromes (CRYs) under red light at 16�C. In addition, disease resistance is inhibited by PHYB under blue light and promoted by CRYs under red light. Therefore, this study reveals a complex interaction between light and temperature in modulating rosette growth and disease resistance as well as the contribution of PHYB and CRY to disease resistance.

Chromatic adaptation in lichen phyco- and photobionts

Biologia ◽  
2010 ◽  
Vol 65 (4) ◽  
Author(s):  
Bazyli Czeczuga ◽  
Ewa Czeczuga-Semeniuk ◽  
Adrianna Semeniuk
Keyword(s):  
Photosynthetic Pigments ◽  
Light Quality ◽  
Red Light ◽  
Green Light ◽  
Total Content ◽  
Chromatic Adaptation ◽  
Xanthoria Parietina ◽  
Flavoparmelia Caperata ◽  
Peltigera Canina ◽  
Effect Of Light

AbstractThe effect of light quality on the photosynthetic pigments as chromatic adaptation in 8 species of lichens were examined. The chlorophylls, carotenoids in 5 species with green algae as phycobionts (Cladonia mitis, Hypogymnia physodes, H. tubulosa var. tubulosa and subtilis, Flavoparmelia caperata, Xanthoria parietina) and the chlorophyll a, carotenoids and phycobiliprotein pigments in 3 species with cyanobacteria as photobionts (Peltigera canina, P. polydactyla, P. rufescens) were determined. The total content of photosynthetic pigments was calculated according to the formule and particular pigments were determined by means CC, TLC, HPLC and IEC chromatography. The total content of the photosynthetic pigments (chlorophylls, carotenoids) in the thalli was highest in red light (genus Peltigera), yellow light (Xanthoria parietina), green light (Cladonia mitis) and at blue light (Flavoparmelia caperata and both species of Hypogymnia). The biggest content of the biliprotein pigments at red and blue lights was observed. The concentration of C-phycocyanin increased at red light, whereas C-phycoerythrin at green light.In Trebouxia phycobiont of Hypogymnia and Nostoc photobiont of Peltigera species the presence of the phytochromes was observed.

scholarly journals Environment and Sporulation in Phytopathogenic Fungi IV. The Effect of Light on the- Formation of Conidia of Peronospora Tabacina Adam

1963 ◽  
Vol 16 (1) ◽  
pp. 88 ◽  
Author(s):  
IAM Cruickshank
Keyword(s):  
Light Source ◽  
Monochromatic Light ◽  
Continuous Light ◽  
Visible Spectrum ◽  
Phytopathogenic Fungi ◽  
Time Of Day ◽  
Light Conditions ◽  
Low Light ◽  
Maximal Inhibition ◽  
Effect Of Light

Using a leaf�disk technique, an analysis of the effect of light on the sporulation intensity of P. tabacina was carried out. The following points were demonstrated: (I) Under conditions of continuous light, sporulation of P. tabacina is sensitive to very low light intensities. ED5!1 for inhibition of sporulation was 16 ftvV cm- 2 for incandescent light (4 f,c.), and 0�58 p.W cm-2 for a monochromatic light source (469 mpo) in the region of maximum effectiveness. (2) Dark treatments induced sporulation under otherwise continuous light conditions. The response was directly proportional to the length of the exposure to darkness over the period 1�5-7 hr. (3) The time of day at which sporulation occurred could be modified by adjustment of the time of day at which darkness was initiated. (4) Within the visible spectrum, the region exerting maximal inhibition on sporulation occurred at 450-525 mJL.

scholarly journals Influence of light quality on Chlorella growth, photosynthetic pigments and high-valued products accumulation in coastal saline-alkali leachate

2021 ◽  
Author(s):  
Xiao-ya Liu ◽  
Yu Hong ◽  
Wen-ping Gu
Keyword(s):  
Blue Light ◽  
Photosynthetic Pigments ◽  
Lipid Content ◽  
Light Quality ◽  
Specific Growth ◽  
Starch Content ◽  
Red Light ◽  
Monochromatic Light ◽  
Algal Density ◽  
Chlorella Sp

Abstract Using saline-alkali leachate to cultivate microalgae is an effective way to realize the utilization of wastewater and alleviate the shortage of water resources. Light source is usually used as an optimized parameter to further improve the cultivation efficiency of microalgae. In this work, the influence of light qualities on the growth and high-valued substances accumulation of Chlorella sp. HQ in coastal saline-alkali leachate were investigated. The specific growth rate of Chlorella in coastal saline-alkali leachate was 0.27–0.60 d−1. At the end of cultivation, the algal density under blue light reached 8.71 ± 0.15 × 107 cells·mL−1, which was significantly higher than the other light groups. The lipid content in the biomass was 29.31–62.95%, and the highest lipid content and TAGs content were obtained under red light and blue-white mixed light, respectively. Percentages of total chlorophylls (0.81–1.70%) and carotenoids (0.08–0.25%) were obtained in the final biomass of the coastal saline-alkali leachate. In addition, the contents of photosynthetic pigments and three high-valued products under mixed light were higher than those of monochromatic light, and the protein, total sugar and starch content under blue-red mixed light was 1.52–3.76 times, 1.54–3.68 times and 1.06–3.35 times of monochromatic blue light and red light, respectively.

scholarly journals The Role of Leaves in Photocontrol of Flower Bud Abscission in Hibiscus rosa-sinensis L. `Nairobi'

2000 ◽  
Vol 125 (1) ◽  
pp. 31-35 ◽  
Author(s):  
Uulke van Meeteren ◽  
Annie van Gelder
Keyword(s):  
Light Quality ◽  
Light Exposure ◽  
Red Light ◽  
Light Conditions ◽  
Flower Bud ◽  
Light Emitting ◽  
Hibiscus Rosa Sinensis ◽  
Number Of Leaves ◽  
Whole Plants

When compared with exposure to darkness, exposing Hibiscus rosa-sinensis L. `Nairobi' plants to red light (635 to 685 nm, 2.9 μmol·m-2·s-1) delayed flower bud abscission, while exposure to far-red light (705 to 755 nm, 1.7 μmol·m-2·s-1) accelerated this process. Flower bud abscission in response to light quality appears to be controlled partly by the presence of leaves. The delay of bud abscission was positively correlated to the number of leaves being exposed to red light. Excluding the flower buds from exposure to red or far-red light, while exposing the remaining parts of the plants to these light conditions, did not influence the effects of the light exposure on bud abscission. Exposing only the buds to red light by the use of red light-emitting diodes (0.8 μmol·m-2·s-1) did not prevent dark-induced flower bud abscission. Exposing the whole plants, darkness or far-red light could only induce flower bud abscission when leaves were present; bud abscission was totally absent when all leaves were removed. To prevent flower bud abscission, leaves had to be removed before, or at the start of, the far-red light treatment. These results suggest that in darkness or far-red light, a flower bud abscission-promoting signal from the leaves may be involved.

scholarly journals Effect of light quality on the cultivation of chlorella pyrenoidosa

2020 ◽  
Vol 143 ◽  
pp. 02033
Author(s):  
Hancheng Guo ◽  
Zhiguo Fang
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Blue Light ◽  
Optical Density ◽  
Light Quality ◽  
Specific Growth ◽  
Red Light ◽  
Total Lipid Content ◽  
Chlorella Pyrenoidosa ◽  
Effect Of Light

Effect of light quality, including red light, blue light, white light, red and blue mixing light with 8:1, 8:2 and 8:3, on the growth characteristics and metabolite accumulation of chlorella pyrenoidosa was conducted based on light emitting diode (LED). Results showed that chlorella pyrenoidosa grew best under blue light, and the optical density, specific growth rate and biomass of chlorella pyrenoidosa was about 2.4, 0.10 d-1 and 6.4 g·L-1, respectively, while the optical density of chlorella pyrenoidosa was between 1.0 and 1.7, specific growth rate was between 0.06-0.10 d-1 and biomass was between 2.7 and 3.8 g·L-1 under other light quality after 30 days of cultivation. The optical density, specific growth rate and biomass of chlorella pyrenoidosa was approximately 2.05 times, 1.33 times and 2.06 times under blue light than red light, respectively. Moreover, Red and blue mixing light was conducive to the synthesis of chlorophyll a and carotenoids of chlorella pyrenoidosa, and blue light could promote the synthesis of chlorophyll b. Chlorophyll a and carotenoids content of chlorella pyrenoidosa was 13.5 mg·g-1and 5.8 mg·g-1 respectively under red and blue mixing light with 8:1, while it was 8.4 mg·g-1 and 3.6 mg·g-1 respectively under blue light. Red and blue mixing light was more conducive to protein and total lipid content per dry cell of chlorella pyrenoidosa. Protein and total lipid content was 489.3 mg·g-1 and 311.2 mg·g-1 under red and blue mixing light with 8:3, while it was 400.9 mg·g-1 and 231.9 mg·g-1 respectively under blue light.

scholarly journals Growth and Bioactive Compound Synthesis in Cultivated Lettuce Subject to Light-quality Changes

HortScience ◽  
2017 ◽  
Vol 52 (4) ◽  
pp. 584-591 ◽  
Author(s):  
Ki-Ho Son ◽  
Jin-Hui Lee ◽  
Youngjae Oh ◽  
Daeil Kim ◽  
Myung-Min Oh ◽  
...  
Keyword(s):  
Blue Light ◽  
Bioactive Compounds ◽  
Light Quality ◽  
Red Light ◽  
Monochromatic Light ◽  
Bioactive Compound ◽  
Light Emitting ◽  
Compound Synthesis ◽  
Plant Factory ◽  
Ferulic Acids

This study aimed to determine the effect of changes in light quality on the improvement of growth and bioactive compound synthesis in red-leaf lettuce (Lactuca sativa L. ‘Sunmang’) grown in a plant factory with electrical lighting. Lettuce seedlings were subjected to 12 light treatments combining five lighting sources: red (R; 655 nm), blue (B; 456 nm), and different ratios of red and blue light combined with three light-emitting diodes [LEDs (R9B1, R8B2, and R6B4)]. Treatments were divided into control (continuous irradiation of each light source for 4 weeks), monochromatic (changing from R to B at 1, 2, or 3 weeks after the onset of the experiments), and combined (changing from R9B1 to R8B2 or R6B4 at 2 or 3 weeks after the onset of the experiments). Growth and photosynthetic rates of lettuce increased with increasing ratios of red light, whereas chlorophyll and antioxidant phenolic content decreased with increasing ratios of red light. Individual phenolic compounds, including chlorogenic, caffeic, chicoric, and ferulic acids, and kaempferol, showed a similar trend to that of total phenolics. Moreover, transcript levels of phenylalanine ammonia-lyase (PAL) and chalcone synthase (CHS) genes were rapidly upregulated by changing light quality from red to blue. Although the concentration of bioactive compounds in lettuce leaves enhanced with blue light, their contents per lettuce plant were more directly affected by red light, suggesting that biomass as well as bioactive compounds’ accumulation should be considered to enhance phytochemical production. In addition, results suggested that growth and antioxidant phenolic compound synthesis were more sensitive to monochromatic light than to combined light variations. In conclusion, the adjustment of light quality at a specific growth stage should be considered as a strategic tool for improving crop yield, nutritional quality, or both in a plant factory with electrical lighting.

scholarly journals Effect of light quality and quantity on productivity and phycoerythrin concentration in the cryptophyte Rhodomonas sp.

2021 ◽  
Author(s):  
Christos Latsos ◽  
Jasper van Houcke ◽  
Lander Blommaert ◽  
Gabrielle P. Verbeeke ◽  
Jacco Kromkamp ◽  
...  
Keyword(s):  
Light Quality ◽  
Incident Light ◽  
Red Light ◽  
Green Light ◽  
Dry Weight ◽  
Continuous Illumination ◽  
Light Illumination ◽  
Initial Growth ◽  
Light Conditions ◽  
Significant Difference

AbstractThe cryptophyte Rhodomonas sp. is a potential feed source for aquaculture live feed and resource for phycoerythrin (PE) production. This research investigates the influence of light, both quality and quantity, on the biomass productivity, composition and growth rate of Rhodomonas sp. The incident light intensity used in the experiments was 50 μmolphotons m−2 s−1, irrespective of the colour of the light, and cultivation took place in lab-scale flat-panel photobioreactors in turbidostat mode. The highest productivity in volumetric biomass (0.20 gdry weight L−1 day−1), measured under continuous illumination, was observed under green light conditions. Blue and red light illumination resulted in lower productivities, 0.11 gdry weight L−1 day−1 and 0.02 g L−1 day−1 respectively. The differences in production are ascribed to increased absorption of green and blue wavelength by phycoerythrin, chlorophyll and carotenoids, causing higher photosynthetically usable radiation (PUR) from equal photosynthetically absorbed irradiance (PAR). Moreover, phycoerythrin concentration (281.16 mg gDW−1) was stimulated under red light illumination. Because photosystem II (PSII) absorbs poorly red light, the algae had to induce more pigments in order to negate the lower absorption per unit pigment of the incident available photons. The results of this study indicate that green light can be used in the initial growth of Rhodomonas sp. to produce more biomass and, at a later stage, red light could be implemented to stimulate the synthesis of PE. Fourier-transform infrared spectroscopy (FTIR) analysis demonstrated a significant difference between the cells under different light quality, with higher contents of proteins for samples of Rhodomonas sp. cultivated under green light conditions. In comparison, higher carbohydrate contents were observed for cells that were grown under red and blue light.

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