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Author Elkins, C.; Van Iersel, M. W.
Title Supplemental Far-red Light-emitting Diode Light Increases Growth of Foxglove Seedlings Under Sole-source Lighting Type Journal Article
Year 2020 Publication HortTechnology Abbreviated Journal
Volume 30 Issue 5 Pages 564-569
Keywords Plants
Abstract (up) Seedlings may be grown indoors where environmental conditions can be precisely controlled to ensure consistent and reliable production. The optimal spectrum for production under sole-source lighting is currently unknown. Far-red light (λ = 700–800 nm) typically is not a significant part of the spectrum of light-emitting diode (LED) grow lights. However, far-red light is photosynthetically active and can enhance leaf elongation, which may result in larger leaves and increased light interception. We hypothesized that adding far-red light to sole-source lighting would increase the growth of ‘Dalmatian Peach’ foxglove (Digitalis purpurea) seedlings grown under white LED lights, potentially shortening production times. Our objective was to evaluate the effect of far-red light intensities, ranging from 4.0 to 68.8 µmol·m−2·s−1, on the growth and morphology of foxglove seedlings. Foxglove seedlings were grown in a growth chamber with a photosynthetic photon flux density (PPFD) of 186 ± 6.4 μmol·m−2·s−1 and supplemental far-red light intensities ranging from 4.0 to 68.8 µmol·m−2·s−1. As far-red light increased, shoot dry weight, root dry weight, plant height, and plant height/number of leaves increased by 38% (P = 0.004), 20% (P = 0.029), 38% (P = 0.025), and 34% (P = 0.024), respectively, while root weight fraction decreased 16% (P = 0.034). Although we expected supplemental far-red light to induce leaf and/or stem expansion, specific leaf area and compactness (two measures of morphology) were unaffected. Because a 37% increase in total photon flux density (PPFD plus far-red light) resulted in a 34.5% increase in total plant dry weight, the increased growth likely was due to increased photosynthesis rather than a shade-acclimation response. The growth response was linear across the 4.0 to 68.8 µmol·m−2·s−1 range of far-fed light tested, so we were unable to determine a saturating far-red photon flux density.
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Call Number UP @ altintas1 @ Serial 3266
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Author Matzke, E. B.
Title The Effect of Street Lights in Delaying Leaf-Fall in Certain Trees Type Journal Article
Year 1936 Publication American Journal of Botany Abbreviated Journal Amer. J. of Botany
Volume 23 Issue 6 Pages 446-452
Keywords Plants; trees; Carolina poplar; Populus canadensis; London plane; Platanus acerifolia; sycamore; Platanus occidentalis; crack willow; Salix fragilis; New York; New York City
Abstract (up) Street lights in the City of New York cause a retention of the leaves of certain trees: Carolina poplar (Populus canadensis), London plane (Platanus acerifolia), sycamore (Platanus occidentalis), and crack willow (Salix fragilis). Illuminated portions of a tree retain their leaves; shaded portions of the same tree do not. One side of a tree, or the lower part, may thus have numerous leaves, while the other side, and the upper part, may be entirely devoid of foliage. A relatively weak light, at a distance of as much as 45 feet from the tip of the nearest branch, may cause retention of numerous leaves. Light intensity as low as 1 foot candle, or less, may be effective. Some leaves may be retained at least a month, others more than that, beyond the normal season. The orientation of the light with respect to the tree – i.e., north, east, south, and west – is not significant. In Populus canadensis all of the leaves ultimately fall, abscission apparently taking place at the base of the petiole. In Platanus acerifolia and Platanus occidentalis some of the leaves are retained until killed by low temperature; then some of them break off above the base of the petiole. Leaves of the Populus and Platanus species discussed remain green unusually long when receiving additional illumination. Leaves of these same trees do not emerge from the buds earlier in the spring as a result of the additional illumination.
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ISSN 0002-9122 ISBN Medium
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Notes Approved no
Call Number IDA @ john @ Serial 1394
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Author Shor, E.; Potavskaya, R.; Kurtz, A.; Paik, I.; Huq, E.; Green, R.
Title PIF-mediated sucrose regulation of the circadian oscillator is light quality and temperature dependent Type Journal Article
Year 2018 Publication Genes Abbreviated Journal Genes (Basel)
Volume 9 Issue 12 Pages
Keywords Plants
Abstract (up) Studies are increasingly showing that metabolic and circadian (~24 h) pathways are strongly interconnected, with the circadian system regulating the metabolic state of the cell, and metabolic products feeding back to entrain the oscillator. In plants, probably the most significant impact of the circadian system on metabolism is in its reciprocal regulation of photosynthesis; however, the pathways by which this occurs are still poorly understood. We have previously shown that members of the basic helix-loop-helix (bHLH) transcription factor PHYTOCHROME INTERACTING FACTOR (PIF) family are involved in the photosynthate entrainment of the circadian oscillator. In this paper, using Arabidopsis mutants and overexpression lines, we examine how temperature and light quality affect PIF-mediated sucrose signaling to the oscillator and examine the contributions of individual PIF members. Our results also show that the quality of light is important for PIF signaling, with red and blue lights having the opposite effects, and that temperature affects PIF-mediated sucrose signaling. We propose the light sensitivity of PIF-mediated sucrose entrainment of the oscillator may be important in enabling plants to distinguish between sucrose produced de novo from photosynthesis during the day and the sucrose products of starch degradation at the end of the night.
Address Department of Plant and Environmental Sciences, Institute for Life Sciences, Edmond J. Safra Campus, Givat Ram, Hebrew University, Jerusalem 91904, Israel. rgreen@mail.huji.ac.il
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ISSN 2073-4425 ISBN Medium
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Notes PMID:30551669; PMCID:PMC6316277 Approved no
Call Number GFZ @ kyba @ Serial 2155
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Author Eng, R.Y.N.; Tsujita, M.J.; Grodzinski, B.
Title The effects of supplementary HPS lighting and carbon dioxide enrichment on the vegetative growth, nutritional status and flowering characteristics ofChrysanthemum morifoliumRamat Type Journal Article
Year 1985 Publication Journal of Horticultural Science Abbreviated Journal Journal of Horticultural Science
Volume 60 Issue 3 Pages 389-395
Keywords Plants
Abstract (up) Supplementary high pressure sodium (HPS) lighting (140 µmol m−2s−1) and CO2 enrichment (1375 µl l−1) improved the vegetative growth of Chrysanthemum morifolium cv Dramatic by increases in stem length, stem diameter, root weight ratio, dry weight, relative growth and net assimilation rates. Three-week-old chrysanthemums grown under CO2 enrichment and HPS lighting had lower leaf weight and stem weight ratios as well as lower foliar nutrient content than those grown under ambient CO2 and natural light. Plants grown on to maturity under CO2 enrichment and supplementary HPS lighting had the longest stem lengths, the most flowers and greatest increase in dry weight. The combination of both additional light and CO2 was superior to either factor used alone. With 24 h HPS supplementary lighting CO2 enrichment was most effective in improving vegetative growth and flower quality when applied during the daytime. Night CO2 enrichment was not commercially beneficial at the light levels employed in this study.
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ISSN 0022-1589 ISBN Medium
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Notes Approved no
Call Number IDA @ intern @ Serial 2373
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Author Patel, J.S.; Radetsky, L.; Rea, M.S.
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 6 Pages 1321-1330
Keywords Plants
Abstract (up) 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
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Notes Approved no
Call Number GFZ @ kyba @ Serial 1955
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