Effect of the Spectral Quality and Intensity of Light-emitting Diodes on Several Horticultural Crops

Light-emitting diode (LED) lamps signify one of the most important advances in artificial lighting for horticulture over the last few decades. The objective of this study was to compare the cultivation of four horticultural plants using a conventional white LED tube (T0) light against one with a good spectral fit to the maximum photosynthetic response (T1) at two intensities. The experiment was carried out with two types of young lettuce, tomato, and bell pepper plants. In a controlled environment chamber, six and four lamps per square meter were used to achieve high (H) and low (L) intensity, respectively. We measured the lighting parameters illuminance (lux) and photosynthetic photon flux (PPF) intensity (µmol·m−2·s−1). The dry and fresh weight, leaf area (LA), and specific index were measured to gauge plant growth. The photosynthetic activity and energy efficiency (EE) were recorded for each species over 60 days of cultivation. The results clearly demonstrate that, compared with conventional LED lamps, the specific horticultural LED lamps with an improved light spectrum increased the EE of the evaluated vegetables by 26%. At both the studied light intensities, plant growth was clearly more closely linked to the spectral fit of the light to the maximum photosynthetic response recorded by McCree (1972) than to PPF or illuminance (lux). We therefore suggest that a specific, detailed spectral distribution study be conducted to predict the effect of the specific quantity and quality of light used in this study on a single parameter of plant growth.

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Growth and Flowering Responses of Seed-propagated Strawberry Seedlings to Different Photoperiods in Controlled Environment Chambers

HortTechnology ◽

10.21273/horttech04061-18 ◽

2018 ◽

Vol 28 (4) ◽

pp. 453-458 ◽

Cited By ~ 2

Author(s):

Johshin Tsuruyama ◽

Toshio Shibuya

Keyword(s):

High Performance ◽

Light Emitting Diode ◽

Photon Flux ◽

Controlled Environment ◽

Light Emitting ◽

Artificial Lighting ◽

Daily Light Integral ◽

Growth Properties ◽

Performance System ◽

Light Integral

The present study investigated growth properties and flowering response of seed-propagated strawberry (Fragaria ×ananassa) seedlings under artificial lighting with different photoperiods to support the development of a high-performance system for the indoor production of strawberry plug transplants. Seedlings of ‘Elan’ and ‘Yotsuboshi’ were grown for 38 days under sunlight in a greenhouse or under light-emitting diode (LED) illumination with photoperiods of 8/16, 12/12, 16/8, or 24/0 hours (light/dark) in growth chambers. The photosynthetic photon flux (PPF) in these photoperiods was maintained at 350, 230, 175, or 115 μmol·m−2·s−1, respectively, to provide the same daily light integral (DLI) of 10 mol·m−2·d−1. The average of DLI of sunlight was 9.9 mol·m−2·d−1. Seedling growth was greater with the 16- and 24-hour photoperiods than with sunlight even though all three treatments provided about the same DLI. Flower buds of the seedlings grown under longer photoperiods started significantly earlier after transplanting in ‘Elan’ but not in ‘Yotsuboshi’. Thus, strawberry transplant production under artificial lighting with an optimized photoperiod can provide high-quality transplants, although the effectiveness is cultivar-specific.

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Application of Light-emitting Diodes and the Effect of Light Quality on Horticultural Crops: A Review

HortScience ◽

10.21273/hortsci14109-19 ◽

2019 ◽

Vol 54 (10) ◽

pp. 1656-1661 ◽

Cited By ~ 3

Author(s):

Liang Zheng ◽

Huaming He ◽

Weitang Song

Keyword(s):

Plant Growth ◽

Growth And Development ◽

Light Quality ◽

Light Emitting Diode ◽

Spectral Composition ◽

Plant Morphology ◽

Plant Growth And Development ◽

Light Emitting ◽

Horticultural Crops ◽

Physiology And Biochemistry

Plant growth and development relies on light and is influenced by light. Light-emitting diode (LED) technology is nowadays providing the possibility for regulating plant growth and development by modifying light spectral composition. Many researches have been carried out to figure out the effects of light quality on various aspects of plant behaviors, including plant morphology, physiology, and biochemistry. In this review, we summarized those research outputs, in order to give suggestion of light quality application for both research and production purposes, in the field of productional yield, productional quality for horticultural plants including vegetables or ornamentals in difference with cultivation goals.

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A Supervisory Control Strategy for Improving Energy Efficiency of Artificial Lighting Systems in Greenhouses

Energies ◽

10.3390/en14010202 ◽

2021 ◽

Vol 14 (1) ◽

pp. 202

Author(s):

Gianluca Serale ◽

Luca Gnoli ◽

Emanuele Giraudo ◽

Enrico Fabrizio

Keyword(s):

Control Strategy ◽

Light Emitting Diode ◽

Cost Savings ◽

Energy Performance ◽

Lighting System ◽

Light Emitting ◽

Artificial Lighting ◽

Lighting Control ◽

Lighting Systems ◽

Power Densities

Artificial lighting systems are used in commercial greenhouses to ensure year-round yields. Current Light Emitting Diode (LED) technologies improved the system efficiency. Nevertheless, having artificial lighting systems extended for hectares with power densities over 50W/m2 causes energy and power demand of greenhouses to be really significant. The present paper introduces an innovative supervisory and predictive control strategy to optimize the energy performance of the artificial lights of greenhouses. The controller has been implemented in a multi-span plastic greenhouse located in North Italy. The proposed control strategy has been tested on a greenhouse of 1 hectare with a lighting system with a nominal power density of 50 Wm−2 requiring an overall power supply of 1 MW for a period of 80 days. The results have been compared with the data coming from another greenhouse of 1 hectare in the same conditions implementing a state-of-the-art strategy for artificial lighting control. Results outlines that potential 19.4% cost savings are achievable. Moreover, the algorithm can be used to transform the greenhouse in a viable source of energy flexibility for grid reliability.

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Light Emitting Diodes (LEDs) as Agricultural Lighting: Impact and Its Potential on Improving Physiology, Flowering, and Secondary Metabolites of Crops

Sustainability ◽

10.3390/su13041985 ◽

2021 ◽

Vol 13 (4) ◽

pp. 1985

Author(s):

Musa Al Murad ◽

Kaukab Razi ◽

Byoung Ryong Jeong ◽

Prakash Muthu Arjuna Samy ◽

Sowbiya Muneer

Keyword(s):

Crop Production ◽

Morphological Changes ◽

Light Emitting Diode ◽

Crop Productivity ◽

Photon Flux ◽

Flower Initiation ◽

Nutrient Metabolism ◽

Light Emitting ◽

Cultivation Systems ◽

Lighting Systems

A reduction in crop productivity in cultivable land and challenging environmental factors have directed advancement in indoor cultivation systems, such that the yield parameters are higher in outdoor cultivation systems. In wake of this situation, light emitting diode (LED) lighting has proved to be promising in the field of agricultural lighting. Properties such as energy efficiency, long lifetime, photon flux efficacy and flexibility in application make LEDs better suited for future agricultural lighting systems over traditional lighting systems. Different LED spectrums have varied effects on the morphogenesis and photosynthetic responses in plants. LEDs have a profound effect on plant growth and development and also control key physiological processes such as phototropism, the immigration of chloroplasts, day/night period control and the opening/closing of stomata. Moreover, the synthesis of bioactive compounds and antioxidants on exposure to LED spectrum also provides information on the possible regulation of antioxidative defense genes to protect the cells from oxidative damage. Similarly, LEDs are also seen to escalate the nutrient metabolism in plants and flower initiation, thus improving the quality of the crops as well. However, the complete management of the irradiance and wavelength is the key to maximize the economic efficacy of crop production, quality, and the nutrition potential of plants grown in controlled environments. This review aims to summarize the various advancements made in the area of LED technology in agriculture, focusing on key processes such as morphological changes, photosynthetic activity, nutrient metabolism, antioxidant capacity and flowering in plants. Emphasis is also made on the variation in activities of different LED spectra between different plant species. In addition, research gaps and future perspectives are also discussed of this emerging multidisciplinary field of research and its development.

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Increased Plant Quality, Greenhouse Productivity and Energy Efficiency with Broad-Spectrum LED Systems: A Case Study for Thyme (Thymus vulgaris L.)

Plants ◽

10.3390/plants10050960 ◽

2021 ◽

Vol 10 (5) ◽

pp. 960

Author(s):

Jenny Manuela Tabbert ◽

Hartwig Schulz ◽

Andrea Krähmer

Keyword(s):

Broad Spectrum ◽

Energy Savings ◽

Light Emitting Diode ◽

Thymus Vulgaris ◽

Light Spectrum ◽

Light Emitting ◽

Biomass Yields ◽

Lighting Systems

A light-emitting diode (LED) system covering plant-receptive wavebands from ultraviolet to far-red radiation (360 to 760 nm, “white” light spectrum) was investigated for greenhouse productions of Thymus vulgaris L. Biomass yields and amounts of terpenoids were examined, and the lights’ productivity and electrical efficiency were determined. All results were compared to two conventionally used light fixture types (high-pressure sodium lamps (HPS) and fluorescent lights (FL)) under naturally low irradiation conditions during fall and winter in Berlin, Germany. Under LED, development of Thymus vulgaris L. was highly accelerated resulting in distinct fresh yield increases per square meter by 43% and 82.4% compared to HPS and FL, respectively. Dry yields per square meter also increased by 43.1% and 88.6% under LED compared to the HPS and FL lighting systems. While composition of terpenoids remained unaffected, their quantity per gram of leaf dry matter significantly increased under LED and HPS as compared to FL. Further, the power consumption calculations revealed energy savings of 31.3% and 20.1% for LED and FL, respectively, compared to HPS. In conclusion, the implementation of a broad-spectrum LED system has tremendous potential for increasing quantity and quality of Thymus vulgaris L. during naturally insufficient light conditions while significantly reducing energy consumption.

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Continuous LED Lighting Enhances Yield and Nutritional Value of Four Genotypes of Brassicaceae Microgreens

Plants ◽

10.3390/plants11020176 ◽

2022 ◽

Vol 11 (2) ◽

pp. 176

Author(s):

Tatjana G. Shibaeva ◽

Elena G. Sherudilo ◽

Alexandra A. Rubaeva ◽

Alexander F. Titov

Keyword(s):

Antioxidant Enzymes ◽

Nutritional Value ◽

Light Emitting Diode ◽

Leaf Mass Per Area ◽

Guaiacol Peroxidase ◽

Enzymatic Antioxidants ◽

Light Spectrum ◽

Light Emitting ◽

Led Lighting ◽

Nutritional Benefits

The effect of continuous lighting (CL, 24 h) and light spectrum on growth and nutritional quality of arugula (Eruca sativa), broccoli (Brassica oleracea var. italic), mizuna (Brassica rapa. var. nipposinica), and radish (Raphanus sativus var. radicula) were investigated in growth chambers under light-emitting diode (LED) and fluorescent lighting. Microgreens were grown under four combinations of two photoperiods (16 h and 24 h) providing daily light integral (DLI) of 15.6 and 23.3 mol m−2 day−1, correspondingly) with two light spectra: LED lamps and fluorescent lamps (FLU). The results show that fresh and dry weights as well as leaf mass per area and robust index of harvested arugula, broccoli, mizuna, and radish seedlings were significantly higher under CL compared to 16 h photoperiod regardless of light quality. There were no visible signs of leaf photodamage. In all CL-treated plants higher chlorophyll a/b and carotenoid-to-chlorophyll ratios were observed in all plants except mizuna. CL treatment was beneficial for anthocyanin, flavonoid, and proline accumulation. Higher activities of antioxidant enzymes (catalase, superoxide dismutase, ascorbate peroxidase, and guaiacol peroxidase) were also observed in CL-treated plants. In most cases, the effects were more pronounced under LED lighting. These results indicate that plants under mild oxidative stress induced by CL accumulated more non-enzymatic antioxidants and increased the activities of antioxidant enzymes. This added nutritional value to microgreens that are used as functional foods providing health benefits. We suggest that for arugula, broccoli, mizuna, and radish, an LED CL production strategy is possible and can have economic and nutritional benefits.

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Effect of Light Spectrum on Gas Exchange, Growth and Biochemical Characteristics of Einkorn Seedlings

Agronomy ◽

10.3390/agronomy10071042 ◽

2020 ◽

Vol 10 (7) ◽

pp. 1042 ◽

Cited By ~ 1

Author(s):

Maria Luce Bartucca ◽

Daniele Del Buono ◽

Eleonora Ballerini ◽

Paolo Benincasa ◽

Beatrice Falcinelli ◽

...

Keyword(s):

Nutritional Status ◽

Light Emitting Diode ◽

Co2 Assimilation ◽

Photon Flux ◽

Photon Flux Density ◽

Vegetable Production ◽

Light Spectrum ◽

Beneficial Effects ◽

Iron And Zinc ◽

Effect Of Light

The use of Light Emitting Diode (LED) lights in microscale vegetable production is more and more widespread. In this context, the effect of light spectrum on photosynthesis, growth, shoot yield, pigment content, and nutritional status of einkorn seedlings (Triticum monococcum L. ssp. monococcum), germinated and grown in a nutrient solution, was investigated. Plants were subjected to six different LED light treatments, all having a photon flux density (PFD) of 200 μmol m−2 s−1. Two light treatments were monochromatic (red or blue), three dichromatic (blue and red in the proportion), and one of a wider spectrum (selected as a control). All the light treatments affected the morphological, biochemical, and nutritional status of einkorn seedlings. Overall, the dichromatic treatments were the most effective in stimulating biomass production, CO2 assimilation, and evapotranspiration, as well as contents in chlorophyll a and b and carotenoids, and additionally nitrogen, phosphorous, manganese, iron, and zinc. These results are of relevance for the beneficial effects of dichromatic LED treatments in maximizing einkorn shoot yield and nutritional values, and in limiting energy consumption in indoor cultivation.

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Changes in light spectra modify secondary compound concentrations and BVOC emissions of Norway spruce seedlings

Canadian Journal of Forest Research ◽

10.1139/cjfr-2020-0120 ◽

2020 ◽

Author(s):

Minna Kivimäenpää ◽

Virpi Virjamo ◽

Rajendra Prasad Ghimire ◽

Jarmo Holopainen ◽

Riitta Julkunen-Tiitto ◽

...

Keyword(s):

Norway Spruce ◽

Blue Light ◽

White Light ◽

Carbon Allocation ◽

Light Emitting Diode ◽

Abiotic Stress Tolerance ◽

Photon Flux ◽

Emission Rates ◽

Light Emitting ◽

Light Spectra

Our objective was to study how changes in the light spectra affects growth, carbohydrate, chlorophyll, carotenoid, terpene, alkaloid and phenolic concentrations, and BVOC (biogenic volatile organic compound) emissions of Norway spruce (Picea abies) seedlings. This study was conducted during the growth of the third needle generation in plant growth chambers. Two light spectra with the main difference in proportion of blue light (400-500 nm) and equal photon flux densities were provided by LED (light-emitting diode) lamps: 1) control (white light + 12 % blue light) and 2) increased blue light (+B) (white light + 45% blue light). The +B treatment increased needle concentrations of total flavonoids and acetophenones. The major changes in the phenolic profile were an accumulation of astragalin derivatives and the aglycone of picein. +B decreased concentrations of the main alkaloid compound, epidihydropinidine, and it’s precursor, 2-methyl-6-propyl-1,6-piperideine, emission rates of limonene, myrcene and total monoterpenes, and concentrations of a few terpenoid compounds, mainly in stems. Growth, needle carbohydrates and pigments were not affected. The results suggest that supplemental blue light shifts carbon allocation between secondary metabolism routes, from alkaloid and terpenoid synthesis to flavonoid and acetophenone synthesis. The changes may affect herbivory and abiotic stress tolerance of Norway spruce.

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The Influence of Artificial Lighting Systems on the Cultivation of Algae: The Example of Chlorella vulgaris

Energies ◽

10.3390/en13225994 ◽

2020 ◽

Vol 13 (22) ◽

pp. 5994

Author(s):

Beata Brzychczyk ◽

Tomasz Hebda ◽

Norbert Pedryc

Keyword(s):

Chlorella Vulgaris ◽

Light Emitting Diode ◽

Radiant Energy ◽

Biodiesel Production ◽

Light Emitting ◽

Artificial Lighting ◽

Single Side ◽

Biological Compounds ◽

Lower Light ◽

Lighting Systems

Microalgae are a practical source of biological compounds for biodiesel production. This study examined the influence of three different light-emitting diode (LED) systems on the biomass production of green algae Chlorella vulgaris BA0002a. The cultivation was carried out in a photobioreactor illuminated from the bottom with a single side light jacket (PBR I), in a photobioreactor illuminated from the bottom with a double side light jacket (PBR II) and in a photobioreactor illuminated only from the top (PBR III). Research has shown that the intensification of algae cell production and growth depends on the light distribution and exposure time of a single cell to radiation. In the experiment, the highest growth of algae cells was obtained in the photobioreactor with double jacket and lower light panel. The lowest cell growth was observed in the photobioreactor illuminated only from above. For cultures raised in the PBR I and PBR II photobioreactors, increased oxygen production was observed, which was directly related to the increased production of biomass, which in turn was dependent on the increased amount of radiant energy.

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A dual-emitting core–shell carbon dot–silica–phosphor composite for LED plant grow light

RSC Advances ◽

10.1039/c7ra00227k ◽

2017 ◽

Vol 7 (27) ◽

pp. 16662-16667 ◽

Cited By ~ 11

Author(s):

Li Wang ◽

Haoran Zhang ◽

Xiaohua Zhou ◽

Yingliang Liu ◽

Bingfu Lei

Keyword(s):

Disease Prevention ◽

Plant Growth ◽

Light Emitting Diodes ◽

Core Shell ◽

Carbon Dot ◽

Light Emitting ◽

Artificial Lighting

Light-emitting diodes (LEDs) are widely used for artificial lighting in plant factories and have been applied for disease prevention and for accelerating plant growth.

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