Cuttings of Impatiens, Pelargonium, and Petunia Propagated under Light-emitting Diodes and High-pressure Sodium Lamps Have Comparable Growth, Morphology, Gas Exchange, and Post-transplant Performance

Increasing photosynthetic daily light integral (DLI) by supplementing with high-pressure sodium (HPS) lamps during propagation has been shown to enhance photosynthesis and biomass accumulation of cuttings. The development of high-intensity light-emitting diodes (LEDs) is a promising technology with potential as a greenhouse supplemental lighting source. Our objective was to quantify the impact of narrow spectra supplemental lighting from LEDs on growth, morphology, and gas exchange of cuttings compared with traditional HPS supplemental lighting. Cuttings of Impatiens hawkeri W. Bull ‘Celebrette Frost’, Pelargonium ×hortorum L.H. Bailey ‘Designer Bright Red’, and Petunia ×hybrida Vilm. ‘Suncatcher Midnight Blue’ were received from a commercial propagator and propagated in a glass-glazed greenhouse at 23 °C air and substrate temperature set points. After callusing (≈5 mol·m−2·d−1 for 7 days), cuttings were placed under 70 μmol·m−2·s−1 delivered from HPS lamps or LED arrays with varying proportions (%) of red:blue light (100:0, 85:15, or 70:30). After 14 days under supplemental lighting treatments, growth, morphology, and gas exchange of rooted cuttings were measured. There were no significant differences among Impatiens and Pelargonium cuttings grown under different supplemental light sources. However, compared with cuttings propagated under HPS lamps, stem length of Petunia cuttings grown under 100:0 red:blue LEDs was 11% shorter, whereas leaf dry mass, root dry mass, root mass ratios, and root:shoot ratio of cuttings grown under 70:30 red:blue LEDs were 15%, 36%, 17%, and 24% higher, respectively. Supplemental light source had minimal impact on plants after transplant. Our data suggest that LEDs are suitable replacements for HPS lamps as supplemental light sources during cutting propagation.

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Comparison of Supplemental Lighting from High-pressure Sodium Lamps and Light-emitting Diodes during Bedding Plant Seedling Production

HortScience ◽

10.21273/hortsci.49.5.589 ◽

2014 ◽

Vol 49 (5) ◽

pp. 589-595 ◽

Cited By ~ 30

Author(s):

Wesley C. Randall ◽

Roberto G. Lopez

Keyword(s):

High Pressure ◽

Light Emitting Diodes ◽

Dry Mass ◽

Operating Life ◽

High Quality ◽

Light Emitting ◽

Northern Latitudes ◽

Bedding Plant ◽

Supplemental Lighting ◽

Plant Seedlings

Annual bedding plant seedlings or plugs are considered high quality when they are compact, fully rooted transplants with a large stem caliper and high root dry mass. Greenhouses in northern latitudes rely on supplemental lighting (SL) from high-pressure sodium lamps (HPS) during winter months to achieve high-quality, finished plugs. Light-emitting diodes (LEDs) offer higher energy efficiencies, a long operating life, and precise waveband specificity that can eliminate wavebands not considered useful. Seedlings of Antirrhinum, Catharanthus, Celosia, Impatiens, Pelargonium, Petunia, Tagetes, Salvia, and Viola were grown at 21 °C under a 16-hour photoperiod of ambient solar light and SL of 100 μmol·m−2·s–1 from either HPS lamps or LED arrays with varying proportions (%) of red:blue light (100:0, 85:15, or 70:30). Height of Catharanthus, Celosia, Impatiens, Petunia, Tagetes, Salvia, and Viola was 31%, 29%, 31%, 55%, 20%, 9%, and 35% shorter, respectively, for seedlings grown under the 85:15 red:blue LEDs compared with those grown under HPS lamps. Additionally, stem caliper of Antirrhinum, Pelargonium, and Tagetes was 16%, 8%, and 13% larger, respectively, for seedlings grown under the 85:15 red:blue LEDs compared with seedlings grown under HPS lamps. The quality index (QI), a quantitative measurement of quality, was similar for Antirrhinum, Catharanthus, Impatiens, Pelargonium, and Tagetes grown under LEDs and HPS lamps. However, it was significantly higher for Petunia, Salvia, and Viola under 85:15, 70:30, and 100:0 red:blue LEDs than under HPS lamps, respectively. These results indicate that seedling quality for the majority of the species tested under SL from LEDs providing both red and blue light was similar or higher than those grown under HPS lamps.

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Long-Term Comparison of Attraction of Flying Insects to Streetlights after the Transition from Traditional Light Sources to Light-Emitting Diodes in Urban and Peri-Urban Settings

Sustainability ◽

10.3390/su11226198 ◽

2019 ◽

Vol 11 (22) ◽

pp. 6198 ◽

Cited By ~ 5

Author(s):

Roy H. A. van Grunsven ◽

Julia Becker ◽

Stephanie Peter ◽

Stefan Heller ◽

Franz Hölker

Keyword(s):

Light Emitting Diodes ◽

Spectral Composition ◽

Mercury Vapor ◽

World Market ◽

Relative Difference ◽

Urban Setting ◽

Light Sources ◽

Urban Settings ◽

Light Emitting ◽

The Impact

Among the different light sources used for street lighting, light-emitting diodes (LEDs) are likely to dominate the world market in the coming years. At the same time, the spectral composition of nocturnal illumination is changing. Europe and many other areas worldwide have implemented bans on energy-inefficient lamps, such as the still very common mercury vapor lamps. However, the impact of artificial light on insects is mostly tested with light-traps or flight-intercept traps that are used for short periods only. By comparing the numbers of insects attracted by street lamps before and after replacing mercury vapor light sources (MV) with light emitting diodes, we assessed the impact in more typical (urban and peri-urban) settings over several years. We found that LED attracted approximately half of the number of insects compared to MV lights. Furthermore, most insect groups are less drawn by LED than by MV, while Hymenoptera are less attracted by MV than by LED. Thus, the composition of the attracted communities differed between the light sources, which may impact ecosystem processes and functions. In green peri-urban settings more insects are attracted than in an urban setting, but the relative difference between the light sources is the same.

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Light Intensity and Quality from Sole-source Light-emitting Diodes Impact Growth, Morphology, and Nutrient Content of Brassica Microgreens

HortScience ◽

10.21273/hortsci.51.5.497 ◽

2016 ◽

Vol 51 (5) ◽

pp. 497-503 ◽

Cited By ~ 14

Author(s):

Joshua R. Gerovac ◽

Joshua K. Craver ◽

Jennifer K. Boldt ◽

Roberto G. Lopez

Keyword(s):

Light Emitting Diodes ◽

Dry Weight ◽

Nutrient Content ◽

Sole Source ◽

Photon Flux ◽

Light Sources ◽

Growth Morphology ◽

Hypocotyl Length ◽

Photoelectric Conversion ◽

Light Emitting

Multilayer vertical production systems using sole-source (SS) lighting can be used for the production of microgreens; however, traditional SS lighting methods can consume large amounts of electrical energy. Light-emitting diodes (LEDs) offer many advantages over conventional light sources, including high photoelectric conversion efficiencies, narrowband spectral light quality (LQ), low thermal output, and adjustable light intensities (LIs). The objective of this study was to quantify the effects of SS LEDs of different light qualities and intensities on growth, morphology, and nutrient content of Brassica microgreens. Purple kohlrabi (Brassica oleracea L. var. gongylodes L.), mizuna (Brassica rapa L. var. japonica), and mustard [Brassica juncea (L.) Czern. ‘Garnet Giant’] were grown in hydroponic tray systems placed on multilayer shelves in a walk-in growth chamber. A daily light integral (DLI) of 6, 12, or 18 mol·m−2·d−1 was achieved from commercially available SS LED arrays with light ratios (%) of red:green:blue 74:18:8 (R74:G18:B8), red:blue 87:13 (R87:B13), or red:far-red:blue 84:7:9 (R84:FR7:B9) with a total photon flux (TPF) from 400 to 800 nm of 105, 210, or 315 µmol·m−2·s−1 for 16 hours. Regardless of LQ, as the LI increased from 105 to 315 µmol·m−2·s−1, hypocotyl length (HL) decreased and percent dry weight (DW) increased for kohlrabi, mizuna, and mustard microgreens. With increasing LI, leaf area (LA) of kohlrabi generally decreased and relative chlorophyll content (RCC) increased. In addition, nutrient content increased under low LIs regardless of LQ. The results from this study can help growers to select LIs and LQs from commercially available SS LEDs to achieve preferred growth characteristics of Brassica microgreens.

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Comparison of Intracanopy Light-emitting Diode Towers and Overhead High-pressure Sodium Lamps for Supplemental Lighting of Greenhouse-grown Tomatoes

HortTechnology ◽

10.21273/horttech.23.1.93 ◽

2013 ◽

Vol 23 (1) ◽

pp. 93-98 ◽

Cited By ~ 47

Author(s):

Celina Gómez ◽

Robert C. Morrow ◽

C. Michael Bourget ◽

Gioia D. Massa ◽

Cary A. Mitchell

Keyword(s):

High Pressure ◽

Energy Consumption ◽

Energy Savings ◽

Light Emitting Diode ◽

Significant Proportion ◽

Fruit Production ◽

Light Sources ◽

Node Number ◽

Light Emitting ◽

Supplemental Lighting

Electric supplemental lighting can account for a significant proportion of total greenhouse energy costs. Thus, the objectives of this study were to compare high-wire tomato (Solanum lycopersicum) production with and without supplemental lighting and to evaluate two different lighting positions + light sources [traditional high-pressure sodium (HPS) overhead lighting (OHL) lamps vs. light-emitting diode (LED) intracanopy lighting (ICL) towers] on several production and energy-consumption parameters for two commercial tomato cultivars. Results indicated that regardless of the lighting position + source, supplemental lighting induced early fruit production and increased node number, fruit number (FN), and total fruit fresh weight (FW) for both cultivars compared with unsupplemented controls for a winter-to-summer production period. Furthermore, no productivity differences were measured between the two supplemental lighting treatments. The energy-consumption metrics indicated that the electrical conversion efficiency for light-emitting intracanopy lighting (LED-ICL) into fruit biomass was 75% higher than that for HPS-OHL. Thus, the lighting cost per average fruit grown under the HPS-OHL lamps was 403% more than that of using LED-ICL towers. Although no increase in yield was measured using LED-ICL, significant energy savings for lighting occurred without compromising fruit yield.

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Photosynthetic Efficiency and Anatomical Structure of Pepper Leaf (Capsicum annuum L.) Transplants Grown under High-Pressure Sodium (HPS) and Light-Emitting Diode (LED) Supplementary Lighting Systems

Plants ◽

10.3390/plants10101975 ◽

2021 ◽

Vol 10 (10) ◽

pp. 1975

Author(s):

Anna Sobczak ◽

Marzena Sujkowska-Rybkowska ◽

Janina Gajc-Wolska ◽

Waldemar Kowalczyk ◽

Wojciech Borucki ◽

...

Keyword(s):

High Pressure ◽

Chlorophyll A ◽

Chlorophyll A Fluorescence ◽

Light Emitting Diodes ◽

Photochemical Efficiency ◽

Photosynthetic Apparatus ◽

Light Emitting ◽

Fluorescence Measurements ◽

Supplemental Lighting ◽

Lighting Systems

The aim of this study was to evaluate the effects of various supplemental greenhouse lighting systems, i.e., high-pressure sodium lamps and mixtures of red and blue light-emitting diodes, on the photochemical efficiency, anatomical leaf structure, and growth of the two pepper cultivars. The intensity levels of the photosynthetically active radiation were the same for both light treatments. In this study, the relative chlorophyll content was measured. Additionally, certain parameters of chlorophyll a fluorescence were measured under ambient light or after dark adaptation. The obtained results showed that the application of light-emitting diodes (LEDs) as supplemental lighting positively affected the anatomical leaf characteristics and plant growth. The leaves of both pepper cultivars were thicker and had larger palisade parenchyma cells under LED supplemental lighting compared to leaves grown under high-pressure sodium (HPS) lamps. Moreover, the mesophyll cells of seedlings grown under LEDs contained more chloroplasts than those growing under HPS lighting. The chlorophyll a fluorescence measurements of pepper seedlings grown under LEDs showed significant increases in photosynthetic apparatus performance index (PI) values compared to plants grown under HPS lamps; however, the values for this index were higher in cv. ‘Aifos’ as compared to cv. ‘Palermo’. We recommend that supplemental lighting systems are applied with caution, as their performance appears to depend not only on the light spectrum but also on the cultivar.

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Tomatoes Grown with Light-emitting Diodes or High-pressure Sodium Supplemental Lights have Similar Fruit-quality Attributes

HortScience ◽

10.21273/hortsci.50.10.1498 ◽

2015 ◽

Vol 50 (10) ◽

pp. 1498-1502 ◽

Cited By ~ 10

Author(s):

Michael P. Dzakovich ◽

Celina Gómez ◽

Cary A. Mitchell

Keyword(s):

High Pressure ◽

Fruit Quality ◽

Light Emitting Diodes ◽

Tomato Fruit ◽

Titratable Acidity ◽

Attractive Alternative ◽

Light Emitting ◽

Sensory Data ◽

Lighting Energy ◽

Supplemental Lighting

Light-emitting diodes (LEDs) are an attractive alternative to high-pressure sodium (HPS) lamps for plant growth because of their energy-saving potential. However, the effects of supplementing broad-waveband solar light with narrow-waveband LED light on the sensory attributes of greenhouse-grown tomatoes (Solanum lycopersicum) are largely unknown. Three separate studies investigating the effect of supplemental light quantity and quality on physicochemical and organoleptic properties of greenhouse-grown tomato fruit were conducted over 4- or 5-month intervals during 2012 and 2013. Tomato cultivars Success, Komeett, and Rebelski were grown hydroponically within a high-wire trellising system in a glass-glazed greenhouse. Chromacity, Brix, titratable acidity, electrical conductivity (EC), and pH measurements of fruit extracts indicated plant response differences between lighting treatments. In sensory panels, tasters ranked tomatoes for color, acidity, and sweetness using an objective scale, whereas color, aroma, texture, sweetness, acidity, aftertaste, and overall approval were ranked using hedonic scales. By collecting both physicochemical as well as sensory data, this study was able to determine whether statistically significant physicochemical parameters of tomato fruit also reflected consumer perception of fruit quality. Sensory panels indicated that statistically significant physicochemical differences were not noticeable to tasters and that tasters engaged in blind testing could not discern between tomatoes from different supplemental lighting treatments or unsupplemented controls. Growers interested in reducing supplemental lighting energy consumption by using intracanopy LED (IC-LED) supplemental lighting need not be concerned that the quality of their tomato fruits will be negatively affected by narrow-band supplemental radiation at the intensities and wavelengths used in this study.

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Application of Light-Emitting Diodes for Improving the Nutritional Quality and Bioactive Compound Levels of Some Crops and Medicinal Plants

Molecules ◽

10.3390/molecules26051477 ◽

2021 ◽

Vol 26 (5) ◽

pp. 1477

Author(s):

Woo-Suk Jung ◽

Ill-Min Chung ◽

Myeong Ha Hwang ◽

Seung-Hyun Kim ◽

Chang Yeon Yu ◽

...

Keyword(s):

Plant Growth ◽

In Vitro Culture ◽

Light Emitting Diodes ◽

Photosynthetic Pigment ◽

Antioxidant Properties ◽

Light Sources ◽

Light Emitting ◽

Cell Defense ◽

Led Irradiation

Light is a key factor that affects phytochemical synthesis and accumulation in plants. Due to limitations of the environment or cultivated land, there is an urgent need to develop indoor cultivation systems to obtain higher yields with increased phytochemical concentrations using convenient light sources. Light-emitting diodes (LEDs) have several advantages, including consumption of lesser power, longer half-life, higher efficacy, and wider variation in the spectral wavelength than traditional light sources; therefore, these devices are preferred for in vitro culture and indoor plant growth. Moreover, LED irradiation of seedlings enhances plant biomass, nutrient and secondary metabolite levels, and antioxidant properties. Specifically, red and blue LED irradiation exerts strong effects on photosynthesis, stomatal functioning, phototropism, photomorphogenesis, and photosynthetic pigment levels. Additionally, ex vitro plantlet development and acclimatization can be enhanced by regulating the spectral properties of LEDs. Applying an appropriate LED spectral wavelength significantly increases antioxidant enzyme activity in plants, thereby enhancing the cell defense system and providing protection from oxidative damage. Since different plant species respond differently to lighting in the cultivation environment, it is necessary to evaluate specific wavebands before large-scale LED application for controlled in vitro plant growth. This review focuses on the most recent advances and applications of LEDs for in vitro culture organogenesis. The mechanisms underlying the production of different phytochemicals, including phenolics, flavonoids, carotenoids, anthocyanins, and antioxidant enzymes, have also been discussed.

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Electrically driven single microribbon based near-infrared exciton-polariton light-emitting diode

CrystEngComm ◽

10.1039/d1ce00419k ◽

2021 ◽

Author(s):

Mingming Jiang ◽

Fupeng Zhang ◽

Kai Tang ◽

Peng Wan ◽

Caixia Kan

Keyword(s):

High Performance ◽

Near Infrared ◽

Light Emitting Diodes ◽

Light Emitting Diode ◽

Light Sources ◽

Coherent Light ◽

Light Emitting ◽

Exciton Polaritons ◽

Laser Devices

Achieving electrically-driven exciton-polaritons has drawn substantial attention toward developing ultralow-threshold coherent light sources, containing polariton laser devices and high-performance light-emitting diodes (LEDs). In this work, we demonstrate an electrically driven...

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Four color stacked white organic light-emitting diodes utilizing the concept of triplet harvesting

MRS Proceedings ◽

10.1557/opl.2011.3 ◽

2011 ◽

Vol 1286 ◽

Author(s):

Th. C. Rosenow ◽

S. Olthof ◽

S. Reineke ◽

B. Lüssem ◽

K. Leo

Keyword(s):

Light Emitting Diodes ◽

Blue Emission ◽

Organic Light Emitting Diodes ◽

Light Sources ◽

Emission Layer ◽

Light Emitting ◽

Organic Light ◽

Blue Emitters ◽

Color Rendering ◽

Triplet Harvesting

ABSTRACTOrganic light-emitting diodes (OLEDs) are developing into a competitive alternative to conventional light sources. Nevertheless, OLEDs need further improvement in terms of efficiency and color rendering for lighting applications. Fluorescent blue emitters allow deep blue emission and high stability, while phosphorescent blue emitter still suffer from insufficient stability. The concept of triplet harvesting is the key for achieving internal quantum efficiencies up to 100 % and simultaneously benefiting from the advantages of fluorescent blue emitters. Here, we present a stacked OLED consisting of two units comprising four different emitters in total. The first unit takes advantage of the concept of triplet harvesting and combines the light emission of a fluorescent blue and a phosphorescent red emitter. The second unit emits light from a single emission layer consisting of a matrix doped with phosphorescent green and yellow emitters. With this approach, we reach white color coordinates close to the standard illuminant A and a color rendering index of above 75. The presented devices are characterized by high luminous efficacies of above 30 lm/W on standard glass substrates without outcoupling enhancement.

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