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

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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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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Optimized LED-Integrated Agricultural Facilities for Adjusting the Growth of Water Bamboo (Zizania latifolia)

Applied Sciences ◽

10.3390/app10041330 ◽

2020 ◽

Vol 10 (4) ◽

pp. 1330

Author(s):

Vincent K. S. Hsiao ◽

Teng-Yun Cheng ◽

Chih-Feng Chen ◽

Hao Shiu ◽

Yong-Jin Yu ◽

...

Keyword(s):

Light Emitting Diode ◽

Winter Season ◽

Lighting System ◽

Zizania Latifolia ◽

Light Emitting ◽

Led Lighting ◽

Led Light ◽

Bamboo Leaves

We investigated a light emitting diode (LED) lighting system applied to a water bamboo field during winter season at night, and the results indicated that this lighting system can prevent the stunting of water bamboo leaves and further assist its growth. Compared with previous LED systems, in which the LED bulbs were placed directly above water bamboo leaves, our LED lighting system presents the benefit of easy handling during harvest. To prevent the inhomogeneous coverage of LED light patterns, a new design of LED lenses was also incorporated.

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Design of Light Emitting Diodes (LEDs) Lighting System and Its Application in Garden Landscape Decoration

Journal of Nanoelectronics and Optoelectronics ◽

10.1166/jno.2020.2793 ◽

2020 ◽

Vol 15 (6) ◽

pp. 734-742

Author(s):

Hailiang Liu ◽

Jiade Cheng ◽

Asnidar Hanim Yusuf

Keyword(s):

Control System ◽

Large Scale ◽

Light Emitting Diode ◽

Image Data ◽

Junction Temperature ◽

Lighting System ◽

Light Emitting ◽

Led Lighting ◽

Arm Processor ◽

Control Node

Light Emitting Diode (LED) is widely used in garden landscape decoration because of its small size, low power, concentrated light, and the capability of showing more vivid colors. While designing the LED lighting system, considering that a single Advanced RISC Machine (ARM)-based control system cannot achieve large-scale LED display, and a single Field Programmable Gate Array (FPGA)-based control system cannot control the lighting system well, an LED system with the combination of ARM processor-FPGA is proposed. In this system, the ARM processor is used as the major control component. The Linux system realizes remote monitoring and intelligent management of image data. In addition, FPGA is used for LED data output. The lighting system consists of a major control node and a lighting node. The nodes are connected in parallel through a chain network. The major control node uses an ARM Cortex processor and is equipped with a Linux operating system. The lighting node uses ARM + FPGA hardware architecture. During the experiments, the LED lighting system is tested first. The results show that the reading and writing speed is fast. The LED display screen meets the lighting requirements. This LED lighting system is used for night lighting of garden landscapes. During the brightness test, the brightness of lighting objects and the background is used as research objects. Experiments have proved that the ratio of the lighting object brightness to the background brightness between (Yu, M. and Li, X., 2012. A little current k-factor method for measuring junction temperature of aviation lighting power led. Guangxue Jishu/Optical Technique, 38(3), pp.371–375; Monas, A., Verma, A., Gawari, A. and Paswan, R. S., 2016. Portable network monitor using arm processor. Procedia Computer Science, 92, pp.493–497.) is suitable for night lighting of garden landscape decoration, which will not bring discomfort to people who enjoy night scenery.

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LIGHT-EMITTING DIODE (LED) LIGHTING IN PLANT PROPAGATION©

Acta Horticulturae ◽

10.17660/actahortic.2015.1085.7 ◽

2015 ◽

pp. 35-37

Author(s):

M. Mansfield

Keyword(s):

Light Emitting Diode ◽

Plant Propagation ◽

Light Emitting ◽

Led Lighting

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The Color Mixing White-Light LEDs

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.378.440 ◽

2013 ◽

Vol 378 ◽

pp. 440-443

Author(s):

Chiu Jung Yang ◽

Chien Sheng Huang ◽

Chih Wei Chen ◽

Po Wen Chen

Keyword(s):

White Light ◽

Light Emitting Diode ◽

Optical Power ◽

Integrating Sphere ◽

Light Spectrum ◽

Light Emitting ◽

Driver Circuit ◽

Color Mixing ◽

Color Rendering

Thepaperis discussedin coloruniformity study.The experiment divided into two steps in this study,first is modules design and simulation. Second is fabrication and measurement.After measure the LEDs property, calculating the ratio of each colored LEDs by using Grassmanns Law,modeling by Solidworks, and simulating the front study by optical software TracePro.Using four-color mixing with self-developed formula to avoid the present white light emitting diode patent, and the four-color grains are Red, Green, Blue and adding Y to modify the overall quality of the mixed light.The phosphorproduceSteabler-Wronsk hardly in the high temperatureas compared tofour-color mixing.Using four-color mixing to producehigher color rendering index than yellow phosphor.Series-parallel array of grain arrangement adopted to achieve the high demand for uniformity, while simplifying the design conditions by a certain current instead of the general mixed light-driven complex driver circuit,the completion of the mixing module using integrating sphere, light spectrum on the spectrophotometer, optical power, color coordinates values, such as mixing uniformity measurements.The chromaticity coordinates errors after complete results of the mixing module measurement and simulation can be controlled under (0.01x, 0.01y).

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

HortScience ◽

10.21273/hortsci.51.3.268 ◽

2016 ◽

Vol 51 (3) ◽

pp. 268-271 ◽

Cited By ~ 11

Author(s):

Miguel Urrestarazu ◽

Cinthia Nájera ◽

María del Mar Gea

Keyword(s):

Plant Growth ◽

Light Emitting Diode ◽

Photon Flux ◽

Photosynthetic Response ◽

Light Spectrum ◽

Light Emitting ◽

Artificial Lighting ◽

Horticultural Crops ◽

Distribution Study ◽

Environment Chamber

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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Upward LED Lighting from the Base Suppresses Senescence of Lower Leaves and Promotes Flowering in Indoor Rose Management

HortScience ◽

10.21273/hortsci15795-21 ◽

2021 ◽

pp. 1-7

Author(s):

Namiko Yamori ◽

Yoriko Matsushima ◽

Wataru Yamori

Keyword(s):

Leaf Senescence ◽

Light Emitting Diode ◽

Plant Management ◽

Indoor Environments ◽

Flower Buds ◽

Flower Bud ◽

Light Emitting ◽

Led Lighting ◽

Dim Light ◽

Supplemental Lighting

In indoor environments such as hotels, the light intensity is generally insufficient for managing plants, and flower buds often fail to open. Lamps placed above (downward lighting) take up space. We assessed the applicability of lighting from underneath (upward lighting) for the indoor management of roses. We grew plants indoors in dim light for 2 weeks under three conditions: 1) without supplemental lighting, 2) with downward light-emitting diode (LED) lighting, and 3) with LED lighting. We quantified photosynthetic components (chlorophyll and rubisco) and the maximum quantum yield of photosystem II (Fv/Fm, an indicator of plant health) to determine the effects of each treatment on the quality and photosynthetic abilities of the leaves. We determined the ratios of dead and opened flower buds to elucidate the effects of supplemental lighting on flower bud maturation. Management without supplemental lighting decreased the number of flowers and resulted in lower-leaf senescence. Downward LED lighting promoted blooming but also resulted in lower-leaf senescence. However, upward LED lighting promoted blooming and maintained the photosynthetic abilities of the leaves, including the lower leaves. This study shows a strong case for using upward LED lighting in appropriate settings for indoor plant management and LED-based horticulture.

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Thermal Performance of Domestic Replacement A19 LED Lighting Products

Volume 14: Emerging Technologies; Materials: Genetics to Structures; Safety Engineering and Risk Analysis ◽

10.1115/imece2016-67974 ◽

2016 ◽

Cited By ~ 2

Author(s):

Thomas Storey ◽

Robin Rackerby ◽

Heather Dillon ◽

Lydia Gingerich

Keyword(s):

Heat Exchanger ◽

Thermal Performance ◽

Heat Dissipation ◽

Cooling System ◽

Light Emitting Diode ◽

Research Process ◽

Light Emitting ◽

Led Lighting ◽

Proper Design ◽

The Cost

In an effort to create a Light Emitting Diode (LED) lighting system that is as efficient as possible, the heat dissipation system must be accurately measured for proper design and operation. Because LED lighting technology is new, little optimization has been performed on typical cooling system required for most A19 replacement products. This paper describes the research process for evaluating the thermal performance of over 15 LED lighting products and compares their performance to traditional lighting sources, namely incandescent and compact fluorescent (CFL). This process uses radiation and convection to model typical cooling mechanisms for domestic A19 type replacement LED products. The A19 products selected for this investigation had input wattages ranging between 7 to 60 Watts, with outputs ranging from 450 to 1100 lumens. The average LED tested dissipated 43% (± 5%) of the total heat generated in the lighting product through the heat exchanger. The best thermal performance was observed in an LED product that dissipated approximately 58% of the total product heat through the heat exchanger. Results indicate that significant improvements to the current LED heat exchanger designs are possible, which will help lower the cost of future LED products, improve performance, and reduce the environmental footprint of the products.

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Analysis of Modified Current Controller and its Implementation in Automotive LED

International Journal of New Practices in Management and Engineering ◽

10.17762/ijnpme.v6i04.60 ◽

2017 ◽

Vol 6 (04) ◽

pp. 01-06

Author(s):

Prof. Bhushan Thakre, Dr. R.M Thakre

Keyword(s):

Supply Voltage ◽

Light Emitting Diode ◽

Control Voltage ◽

Process Technology ◽

Light Emitting ◽

Led Lighting ◽

Current Controller ◽

Dimming Control ◽

Simulation Purpose ◽

The One

A novel highly dimmable current controller which is a linear one is employed in the application of low power automotive is discussed here. Light Emitting Diode is the one which drives current that is linearly controlled to decrease the intensity of LED to limit the destruction of the LED and improve its reliability. Although many dimming techniques for LED lighting are available, our proposed method outperforms the existing methods in terms of power consumption and the no. of transistors used in the proposed design. This emits 100mA and decrease the LED current which is going linearly based on the theory of dimming control voltage. Toggling of LED is avoided finally in comparison with the existing system. This circuit is developed in 0.18μm process technology and Cadence ADE with Spectre is employed for simulation purpose. The proposed method utilizes a maximum power of 392.85 mW when the supply voltage is 4V and the control voltage is 4V at the temperature of 27oC.

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