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Author Son, K.-H.; Jeon, Y.-M.; Oh, M.-M. url  doi
openurl 
  Title Application of supplementary white and pulsed light-emitting diodes to lettuce grown in a plant factory with artificial lighting Type Journal Article
  Year 2016 Publication Horticulture, Environment, and Biotechnology Abbreviated Journal Hortic. Environ. Biotechnol.  
  Volume 57 Issue (up) 6 Pages 560-572  
  Keywords Plants  
  Abstract Light-emitting diodes (LEDs) are currently undergoing rapid development as plant growth light sources in a plant factory with artificial lighting (PFAL). However, little is known about the effects of supplementary light and pulsed LEDs on plant growth, bioactive compound productions, and energy efficiency in lettuce. In this study, we aimed to determine the effects of supplementary white LEDs (study I) and pulsed LEDs (study II) on red leaf lettuce (Lactuca sativa L. ‘Sunmang’). In study I, six LED sources were used to determine the effects of supplementary white LEDs (RGB 7:1:1, 7:1:2, RWB 7:1:2, 7:2:1, 8:1:1, 8:2:0 [based on chip number] on lettuce). Fluorescent lamps were used as the control. In study II, pulsed RWB 7:2:1 LED treatments (30, 10, 1 kHz with a 50 or 75% duty ratio) were applied to lettuce. In study I, the application of red and blue fractions improved plant growth characteristics and the accumulation of antioxidant phenolic compounds, respectively. In addition, the application of green light increased plant growth, including the fresh and dry weights of shoots and roots, as well as leaf area. However, the substitution of green LEDs with white LEDs induced approximately 3.4-times higher light and energy use efficiency. In study II, the growth characteristics and photosynthesis of lettuce were affected by various combinations of duty ratio and frequency. In particular, biomass under a 1 kHz 75% duty ratio of pulsed LEDs was not significantly different from that of the control (continuous LEDs). Moreover, no significant difference in leaf photosynthetic rate was observed between any pulsed LED treatment utilizing a 75% duty ratio versus continuous LEDs. However, some pulsed LED treatments may potentially improve light and energy use efficiency compared to continuous LEDs. These results suggest that the fraction of red, blue, and green wavelengths of LEDs is an important factor for plant growth and the biosynthesis of bioactive compounds in lettuce and that supplementary white LEDs (based on a combination of red and blue LEDs) might be more suitable as a commercial lighting source than green LEDs. In addition, the use of suitable pulses of LEDs might save energy while inducing plant growth similar to that under continuous LEDs. Our findings provide important basic information for designing optimal light sources for use in a PFAL.  
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  ISSN 2211-3452 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number LoNNe @ kyba @ Serial 1615  
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Author Patel, J.S.; Radetsky, L.; Rea, M.S. url  doi
openurl 
  Title The Value of Red Light at Night for Increasing Basil Yield Type Journal Article
  Year 2018 Publication Canadian Journal of Plant Science Abbreviated Journal Can. J. Plant Sci.  
  Volume 98 Issue (up) 6 Pages 1321-1330  
  Keywords Plants  
  Abstract Sweet basil (<i>Ocimum basilicum L.</i>) is primarily used for culinary purposes, but it is also used in the fragrance and medicinal industries. In the last few years, global sweet basil production has been significantly impacted by downy mildew caused by <i>Peronospora belbahrii</i>. Nighttime exposure to red light has been shown to inhibit sporulation of <i>P. belbahrii</i>. The objective of this study was to determine if nighttime exposure to red light from light-emitting diodes (LEDs; λ<sub>max</sub> = 625 nm) could increase plant growth (plant height and leaf size) and yield (number and weight of leaves) in basil plants. In two sets of greenhouse experiments, red light was applied at a photosynthetic photon flux density (PPFD) of 60 µmol m<sup>-2</sup> s<sup>-1</sup> during the otherwise dark night for 10 hours (from 20:00 to 06:00). The results demonstrate that exposure to red light at night can increase the number of basil leaves per plant, plant height, leaf size (length and width), and leaf fresh and dry weight, compared to plants in darkness at night. The addition of incremental red light at night has the potential to be cost-effective for fresh organic basil production in controlled environments.  
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  ISSN 0008-4220 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 1955  
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Author Bennie, J.; Davies, T.W.; Cruse, D.; Inger, R.; Gaston, K.J.; Lewis, O. url  doi
openurl 
  Title Artificial light at night causes top-down and bottom-up trophic effects on invertebrate populations Type Journal Article
  Year 2018 Publication Journal of Applied Ecology Abbreviated Journal J Appl Ecol  
  Volume 55 Issue (up) 6 Pages 2698-2706  
  Keywords Ecology; Animals; Plants  
  Abstract Globally, many ecosystems are exposed to artificial light at night. Nighttime lighting has direct biological impacts on species at all trophic levels. However, the effects of artificial light on biotic interactions remain, for the most part, to be determined.

We exposed experimental mesocosms containing combinations of grassland plants and invertebrate herbivores and predators to illumination at night over a 3‐year period to simulate conditions under different common forms of street lighting.

We demonstrate both top‐down (predation‐controlled) and bottom‐up (resource‐controlled) impacts of artificial light at night in grassland communities. The impacts on invertebrate herbivore abundance were wavelength‐dependent and mediated via other trophic levels.

White LED lighting decreased the abundance of a generalist herbivore mollusc by 55% in the presence of a visual predator, but not in its absence, while monochromatic amber light (with a peak wavelength similar to low‐pressure sodium lighting) decreased abundance of a specialist herbivore aphid (by 17%) by reducing the cover and flower abundance of its main food plant in the system. Artificial white light also significantly increased the food plant's foliar carbon to nitrogen ratio.

We conclude that exposure to artificial light at night can trigger ecological effects spanning trophic levels, and that the nature of such impacts depends on the wavelengths emitted by the lighting technology employed.

Policy implications. Our results confirm that artificial light at night, at illuminance levels similar to roadside vegetation, can have population effects mediated by both top‐down and bottom‐up effects on ecosystems. Given the increasing ubiquity of light pollution at night, these impacts may be widespread in the environment. These results underline the importance of minimizing ecosystem disruption by reducing light pollution in natural and seminatural ecosystems.
 
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  Language English Summary Language Original Title  
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  ISSN 0021-8901 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number NC @ ehyde3 @ Serial 2086  
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Author Nelson, J.A.; Bugbee, B. url  doi
openurl 
  Title Economic analysis of greenhouse lighting: light emitting diodes vs. high intensity discharge fixtures Type Journal Article
  Year 2014 Publication PloS one Abbreviated Journal PLoS One  
  Volume 9 Issue (up) 6 Pages e99010  
  Keywords Plants  
  Abstract Lighting technologies for plant growth are improving rapidly, providing numerous options for supplemental lighting in greenhouses. Here we report the photosynthetic (400-700 nm) photon efficiency and photon distribution pattern of two double-ended HPS fixtures, five mogul-base HPS fixtures, ten LED fixtures, three ceramic metal halide fixtures, and two fluorescent fixtures. The two most efficient LED and the two most efficient double-ended HPS fixtures had nearly identical efficiencies at 1.66 to 1.70 micromoles per joule. These four fixtures represent a dramatic improvement over the 1.02 micromoles per joule efficiency of the mogul-base HPS fixtures that are in common use. The best ceramic metal halide and fluorescent fixtures had efficiencies of 1.46 and 0.95 micromoles per joule, respectively. We also calculated the initial capital cost of fixtures per photon delivered and determined that LED fixtures cost five to ten times more than HPS fixtures. The five-year electric plus fixture cost per mole of photons is thus 2.3 times higher for LED fixtures, due to high capital costs. Compared to electric costs, our analysis indicates that the long-term maintenance costs are small for both technologies. If widely spaced benches are a necessary part of a production system, the unique ability of LED fixtures to efficiently focus photons on specific areas can be used to improve the photon capture by plant canopies. Our analysis demonstrates, however, that the cost per photon delivered is higher in these systems, regardless of fixture category. The lowest lighting system costs are realized when an efficient fixture is coupled with effective canopy photon capture.  
  Address Crop Physiology Laboratory, Department of Plant Soils and Climate, Utah State University, Logan, Utah, United States of America  
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  Language English Summary Language Original Title  
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  ISSN 1932-6203 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:24905835; PMCID:PMC4048233 Approved no  
  Call Number GFZ @ kyba @ Serial 2233  
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Author Adams, J. url  doi
openurl 
  Title Some Further Experiments On The Relation Of Light To Growth Type Journal Article
  Year 1925 Publication American Journal of Botany Abbreviated Journal American Journal of Botany  
  Volume 12 Issue (up) 7 Pages 398-412  
  Keywords Plants  
  Abstract  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0002-9122 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 2393  
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