Light quality and sun tracking in Malva neglecta

F J. F. Fisher; D. L. Ehret; G. R. Lister; J. Hollingdale

doi:10.1139/b89-072

Light quality and sun tracking in Malva neglecta

Canadian Journal of Botany ◽

10.1139/b89-072 ◽

1989 ◽

Vol 67 (2) ◽

pp. 515-520 ◽

Cited By ~ 13

Author(s):

F J. F. Fisher ◽

D. L. Ehret ◽

G. R. Lister ◽

J. Hollingdale

Keyword(s):

Active Component ◽

Light Quality ◽

Light Treatment ◽

Spectral Quality ◽

Solar Tracking ◽

Spectral Components ◽

Additional Radiation ◽

Direction Of Movement ◽

Quantum Flux ◽

Tracking Movements

Two distinct spectral components were found to be necessary to produce solar-tracking movements of the leaves of Malva neglecta: a small blue vectorial component with a quantum flux as low as 10 μmol∙m−2∙s−1 was found to be sufficient to determine the direction of movement, but responses do not take place unless additional radiation (regardless of spectral quality or direction) raise the total photosynthetically active component above the current light compensation point (70 μmol∙m−2∙s−1). This additional radiation could be given simultaneously or in an immediately preceding light treatment.

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Improving Cannabis Bud Quality and Yield with Subcanopy Lighting

HortScience ◽

10.21273/hortsci13173-18 ◽

2018 ◽

Vol 53 (11) ◽

pp. 1593-1599 ◽

Cited By ~ 4

Author(s):

Dave Hawley ◽

Thomas Graham ◽

Michael Stasiak ◽

Mike Dixon

Keyword(s):

Significant Variation ◽

Light Quality ◽

Cannabis Sativa ◽

Control Treatment ◽

Plant Canopy ◽

Specific Production ◽

Spectral Quality ◽

Terpene Content ◽

Light Spectral Quality ◽

Lower Plant

The influence of light spectral quality on cannabis (Cannabis sativa L.) development is not well defined. It stands to reason that tailoring light quality to the specific needs of cannabis may increase bud quality, consistency, and yield. In this study, C. sativa L. ‘WP:Med (Wappa)’ plants were grown with either no supplemental subcanopy lighting (SCL) (control), or with red/blue (“Red-Blue”) or red-green-blue (“RGB”) supplemental SCL. Both Red-Blue and RGB SCL significantly increased yield and concentration of total Δ9-tetrahydrocannabinol (Δ9-THC) in bud tissue from the lower plant canopy. In the lower canopy, RGB SCL significantly increased concentrations of α-pinine and borneol, whereas both Red-Blue and RGB SCL increased concentrations of cis-nerolidol compared with the control treatment. In the upper canopy, concentrations of α-pinine, limonene, myrcene, and linalool were significantly greater with RGB SCL than the control, and cis-nerolidol concentration was significantly greater in both Red-Blue and RGB SCL treated plants relative to the control. Red-Blue SCL yielded a consistently more stable metabolome profile between the upper and lower canopy than RGB or control treated plants, which had significant variation in cannabigerolic acid (CBGA) concentrations between the upper and lower canopies. Overall, both Red-Blue and RGB SCL treatments significantly increased yield more than the control treatment, RGB SCL had the greatest impact on modifying terpene content, and Red-Blue produced a more homogenous bud cannabinoid and terpene profile throughout the canopy. These findings will help to inform growers in selecting a production light quality to best help them meet their specific production goals.

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The pattern of vascular deployment near the pulvinus of the solar-tracking leaf of Lavatera cretica (Malvaceae)

Canadian Journal of Botany ◽

10.1139/b87-290 ◽

1987 ◽

Vol 65 (10) ◽

pp. 2109-2117 ◽

Cited By ~ 8

Author(s):

F. J. F. Fisher ◽

D. L. Ehret ◽

J. Hollingdale

Keyword(s):

Outer Cylinder ◽

Vascular Pattern ◽

First Order ◽

Flexible Tube ◽

Solar Tracking ◽

Tracking Movements ◽

Lateral Branches ◽

Subsequent Splitting ◽

Coaxial Tube

Distinguishable files of xylem and phloem elements that originate in first-order branches of the seven palmate major veins of Lavatera cretica leaves become separated from files unique to the radially aligned sections of the same veins before entering the pulvinus at the distal end of the petiole. The major veins initially merge to form a double coaxial tube: the outer cylinder comprises files unique to the major veins and the inner cylinder comprises files from lateral branches. Subsequent splitting, unfolding, and recombining of these cylinders results in the single narrow flexible tube constituting the hinge of the pulvinus. Proximal to this point, in L. cretica, the files reseparate into six alternately large and small petiolar bundles. The observed vascular pattern offers a means whereby signals from the lamina that elicit sun-tracking movements by the pulvinus can be integrated.

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Interactive Effects of Light Quality during Day Extension and Temperature on Bud Set, Bud Burst and PaFTL2, PaCOL1-2 and PaSOC1 Expression in Norway Spruce (Picea abies (L.) Karst.)

Forests ◽

10.3390/f12030337 ◽

2021 ◽

Vol 12 (3) ◽

pp. 337

Author(s):

Camilo Chiang ◽

Marcos Viejo ◽

Oda Toresdatter Aas ◽

Katharina T. Hobrak ◽

Christian Bianchi Strømme ◽

...

Keyword(s):

Norway Spruce ◽

Light Quality ◽

Shoot Elongation ◽

Light Treatment ◽

Interactive Effects ◽

Tree Seedlings ◽

Bud Burst ◽

Transcript Levels ◽

Bud Set ◽

Lower Temperature

Light and temperature are crucial factors for the annual growth rhythm of tree seedlings of the boreal and temperate zone. Dormant, vegetative winter buds are formed under short days (SD) and altered light quality. In the conifer Norway spruce, expression of FTL2 increases and PaCOL1-2 and PaSOC1 decrease under light regimes, inducing bud set. Although temperature is known to modulate the timing of bud set, information about combined effects of light climate and temperature on bud phenology and gene expression is limited. We studied the interactive effects of temperature (18, 22/24 °C) and day extension with blue (B), red (R) or far-red (FR) light or different R:FR ratios compared to SD on growth–dormancy cycling and expression of FTL2, PaCOL1-2 and PaSOC1 in Norway spruce seedlings. Day-extension with B light and all treatments involving FR light sustained shoot elongation, with increased growth at higher temperature. The R light treatment resulted in delayed/prevented bud set compared to SD, with more delay/prevented bud set at 24 °C than 18 °C. This was associated with lower PaFTL2-transcript levels at 24 °C and more rapid subsequent bud burst. For the growth-sustaining treatments (long days, FR and B light), the PaFTL2-transcript levels were generally lower and those of PaCO1-2 and PaSOC1 higher compared with SD and R light. In conclusion, our results demonstrate more reduced/prevented bud set and faster bud burst with increased temperature under day extension with R light, indicating less deep dormancy than at lower temperature. Also, sustained shoot elongation under the B light treatment (27 µmol m−2 s−1) in contrast to the lower B light-irradiances tested previously (≤13 µmol m−2 s−1), demonstrates an irradiance-dependent effect of day extension with B light.

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Analysis on light quantity and quality based on diverse cloud conditions

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprsarchives-xl-7-203-2014 ◽

2014 ◽

Vol XL-7 ◽

pp. 203-208

Author(s):

M. Yamashita ◽

M. Yoshimura

Keyword(s):

Cloud Cover ◽

Light Quality ◽

Incident Light ◽

Ground Surface ◽

Light Environment ◽

The Sun ◽

Spectral Components ◽

Light Quantity ◽

The Difference ◽

Light Components

Photosynthetic active radiation (PAR) is the source of incident light energy for the photosynthetic activity of plants. PAR additionally characterizes the light environment on the surface of the Earth. The light environment is an important factor for estimating quantities such as carbon exchange and the productivities of forests and agriculture. The incident PAR on the ground surface has the characteristics of light quantity consists of direct and diffuse components, and of light quality consists of spectral components such blue, green and red lights. These light quantity and quality are also important light environmental factors in the photosynthetic activities of plants under the natural environment. However, the light environment including direct and diffuse components and spectral components is easily affected by cloud conditions especially cloud cover and its movements. In this paper, we focus on the characteristics of the light quantity and quality under diverse cloud conditions, and analyse the observational data, which are the global- and diffuse- spectral irradiances from 400 to 700 nm with quantum and energy units and the cloud conditions derived from whole-sky images taken during summer in Kyoto city. As for the comparisons with light quality and cloud conditions, we use the Normalized Difference PAR Spectral Index (NDPSI) which shows the difference of red- and blue-light components and we use cloud cover and the Sun appearance ratio derived from the wholesky images to define the cloud conditions. As the results of these analyses, we confirmed that there are the clear relationships between cloud cover and diffuse ratio, between the Sun appearance ratio and the normalized global PAR as the light quantity, between cloud cover and NDPSI in diffuse component, and between the Sun appearance ratio and NDPSI in direct component as the light quality.

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Effects of spectral light quality on the growth, productivity, and elemental ratios in differently pigmented marine phytoplankton species

10.1101/2020.04.09.034504 ◽

2020 ◽

Author(s):

T. L. Bercel ◽

S. A. Kranz

Keyword(s):

Light Quality ◽

Light Emitting Diode ◽

Marine Phytoplankton ◽

Phytoplankton Species ◽

Spectral Quality ◽

Elemental Ratios ◽

Light Emitting ◽

Light Spectra ◽

Synechococcus Sp ◽

Pigment Ratios

AbstractEffects of light quality on the growth, productivity, and cellular composition of three uniquely pigmented marine phytoplankton species were characterized. To accomplish this, cultures of Prochlorococcus marinus, Synechococcus sp., and Thalassiosira weissflogii were grown under three commercially available LEDs as well as a fluorescent growth light. Despite having equal photosynthetically active radiation, light quality and thus photosynthetically usable radiation differed between the treatments. Growth was unaffected in all species tested, yet primary productivity was affected in P. marinus and Synechococcus sp. All species regulated cellular carbon and nitrogen quotas as a direct response to light spectra, while cellular chlorophyll a was regulated in Synechococcus sp. and T. weissflogii only. Analysis of pigment ratios revealed minor acclimations in some of the cultures and photophysiological analysis indicated changes in the photoacclimation state between different light environments. These results show that while the species used in our experiment are able to maintain growth when exposed to lights of varying quality, underlying cellular metabolism and biochemistry can be affected. The data presented here highlight the importance of carefully choosing a lighting environment with a defined spectral quality when designing laboratory-based experiments or setting up bioreactors for biomass generation.HighlightWith light emitting diode-based growth lights becoming available to researchers, it is important to consider the spectral quality of light when designing experiments to understand responses of phytoplankton to environmental conditions.

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Stable Reference Gene Selection for qRT-PCR Normalization in Strawberry (Fragaria × ananassa) Leaves under Different Stress and Light-Quality Conditions

Horticulturae ◽

10.3390/horticulturae7110452 ◽

2021 ◽

Vol 7 (11) ◽

pp. 452

Author(s):

Yuntian Ye ◽

Yang Lu ◽

Guangyi Wang ◽

Yongqiang Liu ◽

Yunting Zhang ◽

...

Keyword(s):

Reference Gene ◽

White Light ◽

Reference Genes ◽

Light Quality ◽

Red Light ◽

Light Treatment ◽

Data Normalization ◽

Fragaria Ananassa ◽

Expression Stability ◽

Qrt Pcr

Selecting an appropriate reference gene is of crucial importance for improving the accuracy of qRT-PCR analyses. In this study, strawberry (Fragaria ananassa) seedlings were subjected to different environmental conditions including heat, cold, drought, salt, white-light, blue-light, and red-light treatments. The expression levels of seven candidate reference genes, including Fa18S, FaGAPDH, FaPIRUV, FaDBP, FaHISTH4, FaACTIN1, and FaACTIN2, in the strawberry leaves were measured by qRT-PCR. Then, four programs (geNorm, NormFinder, BestKeeper, and RefFinder) were employed as tools to evaluate the expression stability of the candidate reference genes. The results showed that the expression stability of the reference genes varied under different conditions. For the cold stress and white-light treatments, FaACTIN2 was evaluated to be the most stable reference gene. FaGAPDH should be used as the reference gene under salt-stress condition and red-light treatment. For the data normalization under drought-stress treatment, FaDBP is the recommended reference gene with the highest expression stability. FaHISTH4 was observed to be the best reference gene for data normalization under heat stress and blue-light treatment. This work provides information on selecting reference genes for accurate gene expression analyses of target genes in strawberry leaves under various abiotic stress and light-quality conditions.

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Plant Responses to Light: A Potential Tool for Weed Management

Weed Science ◽

10.1017/s0043174500081509 ◽

1995 ◽

Vol 43 (3) ◽

pp. 474-482 ◽

Cited By ~ 97

Author(s):

Jodie S. Holt

Keyword(s):

Plant Growth ◽

Weed Management ◽

Light Quality ◽

Cropping Systems ◽

Crop Productivity ◽

Plant Responses ◽

Spectral Quality ◽

Plant Canopies ◽

Fluctuating Light ◽

Narrow Row

Light regulates many facets of plant growth and development through the effects of quantity of total energy and of photons, spectral quality, duration, and photoperiod. Numerous techniques and types of equipment are available for quantifying light in plant canopies. The effect of total quantity of light on weed and crop productivity has been described for many cropping systems. Recent work has focused on other aspects of light, in particular, spectral distribution of light (quality), transient light (sunflecks), and plant adaptation to changing light environments. The altered spectral quality of light in a plant canopy affects plant growth and morphology, which in turn affect competition for light. Dynamic plant response to transient light is also important to canopy photosynthesis and productivity. Plant physiological and morphological adaptation to fluctuating light is another potential factor regulating weed/crop interactions. Current cropping practices such as using smother crops and narrow row spacing exploit plant light responses to promote crop growth and suppress weed growth. A better understanding of plant responses to light quality, transient light, and fluctuating light environments will lead to a better understanding of how to manipulate the light environment in crop canopies to improve weed management.

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EFFECTS OF LIGHT SPECTRAL QUALITY ON NUTRIENT UPTAKE BY TOMATO

Canadian Journal of Plant Science ◽

10.4141/cjps88-036 ◽

1988 ◽

Vol 68 (1) ◽

pp. 287-289 ◽

Cited By ~ 3

Author(s):

N. TREMBLAY ◽

M.-C. GASIA ◽

M.-Th. FERAUGE ◽

A. GOSSELIN ◽

M. J. TRUDEL

Keyword(s):

High Pressure ◽

Calcium Uptake ◽

Light Quality ◽

Controlled Environment ◽

Light Sources ◽

Spectral Quality ◽

Mineral Uptake ◽

Tomato Plants ◽

Light Spectral Quality ◽

Nutrient Solutions

Young tomato plants (Lycopersicon esculentum Mill. ’Duranto’) were grown in a controlled environment under three light sources. The plants were fertilized with nutrient solutions containing either 45Ca, 86Rb, 59Fe or 54Mn. Calcium uptake increased significantly under white deluxe and grow-lux lamps as compared to high-pressure sodium, while Rb uptake was higher under gro-lux lamps. No significant differences in uptake were obtained for Fe or Mn among light sources.Key words: Tomato, Isotope, Mineral uptake, Light quality

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