scholarly journals Increasing Levels of Supplemental LED Light Enhances the Rate Flower Development of Greenhouse-grown Cut Gerbera but does not Affect Flower Size and Quality

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1332
Author(s):  
David Llewellyn ◽  
Katherine Schiestel ◽  
Youbin Zheng
Keyword(s):  
Flower Development ◽  
Vegetative Growth ◽  
Light Emitting Diode ◽  
Photon Flux ◽  
Light Emitting ◽  
Led Light ◽  
Linear Relationships ◽  
Content Index ◽  
Supplemental Lighting ◽  
Flower Quality

To investigate the influence of supplemental lighting intensity on the production (i.e., rate of flower development, flower quality, and yield) of cut gerbera during Canada’s supplemental lighting season (November to March), trials were carried out at a research greenhouse. Five supplemental light emitting diode (LED) light intensity (LI) treatments provided canopy-level photosynthetic photon flux densities (PPFD) ranging from 41 to 180 µmol m−2 s−1. With a 12-h photoperiod, the treatments provided 1.76 to 7.72 mol m−2 d−1 of supplemental light. Two cultivars of cut gerbera (Gerbera jamesonii H. Bolus ex Hook.f) were used to evaluate vegetative growth and flower production. Plugs of ‘Ultima’ were assessed for vegetative growth and rate of flower development. There were minor LI treatment effects on number of leaves and chlorophyll content index and flowers from plants under the highest versus the lowest LI matured 10% faster. Reproductively mature ‘Panama’ plants were assessed for flower yield and quality. ‘Panama’ flowers from the highest LI treatment had shorter stems than the three lowest LI treatments, and flowers from the middle LI treatment had larger diameter than the other treatments. Flowers from the lowest LI treatment had lower fresh mass than the three highest LI treatments. There were linear relationships between LI and numbers of flowers harvested, with the highest LI treatment producing 10.3 and 7.0 more total and marketable flowers per plant than the lowest LI treatment. In general, increasing levels of supplemental light had only minor effects on vegetative growth (young plants) and size and quality of harvested flowers (mature plants), but flowers from plants grown under higher LIs were more numerous and matured faster.

scholarly journals Increasing Levels of Supplemental Led Light Enhances the Rate Flower Development of Greenhouse-Grown Cut Gerbera but Does Not Affect Flower Size and Quality

2020 ◽  
Author(s):  
Dave Llewellyn ◽  
Katherine Schiestel ◽  
Youbin Zheng
Keyword(s):  
Flower Development ◽  
Vegetative Growth ◽  
Photon Flux ◽  
Led Light ◽  
Yield And Quality ◽  
Flower Yield ◽  
Linear Relationships ◽  
Content Index ◽  
Lighting Intensity ◽  
Supplemental Lighting

To investigate the influence of supplemental lighting intensity on the production of cut gerbera during Canada’s supplemental lighting season (November to March), trials were carried out at a research greenhouse. Five supplemental LED light intensity (LI) treatments provided canopy-level photosynthetic photon flux densities (PPFD) ranging from 41 to 180 µmol·m-2·s-1. With a 12-h photoperiod, the treatments provided 1.76 to 7.72 mol·m-2·d-1 of supplemental light. Two cultivars of cut gerbera (Gerbera jamesonii H. Bolus ex Hook.f) were used to evaluate vegetative growth and flower production. Plugs of ‘Ultima’ were assessed for vegetative growth and rate of flower development. There were minor LI treatment effects on number of leaves and chlorophyll content index and flowers from plants under the highest vs. lowest LI matured 10% faster. Reproductively mature ‘Panama’ plants were assessed for flower yield and quality. ‘Panama’ flowers from the highest LI treatment had shorter stems than the three lowest LI treatments, flowers from the middle LI treatment had larger diameter than the other treatments. Flowers from the lowest LI treatment had lower fresh mass than the three highest LI treatments. There were linear relationships between LI and numbers of flowers harvested, with the highest LI treatment producing 10.3 and 7.0 more total and marketable flowers per plant than the lowest LI treatment. In general, increasing levels of supplemental light had only minor effects on vegetative growth (young plants) and size and quality of harvested flowers (mature plants) but flowers from plants grown under higher LIs were more numerous and matured faster.

scholarly journals An Adaptive Control Approach for Light-emitting Diode Lights Can Reduce the Energy Costs of Supplemental Lighting in Greenhouses

HortScience ◽  
2017 ◽  
Vol 52 (1) ◽  
pp. 72-77 ◽  
Author(s):  
Marc W. van Iersel ◽  
David Gianino
Keyword(s):  
Duty Cycle ◽  
Light Emitting Diode ◽  
Production Costs ◽  
Photon Flux ◽  
Substantial Part ◽  
Response Curves ◽  
Light Emitting ◽  
Full Power ◽  
Supplemental Lighting ◽  
Led Lights

Supplemental lighting in greenhouses is often needed for year-round production of high-quality crops. However, the electricity needed for supplemental lighting can account for a substantial part of overall production costs. Our objective was to develop more efficient control methods for supplemental lighting, taking advantage of the dimmability of light-emitting diode (LED) grow lights. We compared 14 hours per day of full power supplemental LED lighting to two other treatments: 1) turning the LEDs on, at full power, only when the ambient photosynthetic photon flux (PPF) dropped below a specific threshold, and 2) adjusting the duty cycle of the LEDs so that the LED lights provided only enough supplemental PPF to reach a preset threshold PPF. This threshold PPF was adjusted daily from 50 to 250 μmol·m−2·s−1. Turning the LED lights on at full power and off based on a PPF threshold was not practical since this at times resulted in the lights going on and off frequently. Adjusting the duty cycle of the LED lights based on PPF measurements underneath the light bar provided excellent control of PPF, with 5-minute averages typically being within 0.2 μmol·m−2·s−1 of the threshold PPF. Continuously adjusting the duty cycle of the LED lights reduced electricity use by 20% to 92%, depending on the PPF threshold and daily light integral (DLI) from sunlight. Simulations based on net photosynthesis (An) − PPF response curves indicated that there are large differences among species in how efficiently supplemental PPF stimulates An. When there is little or no sunlight, An of Heuchera americana is expected to increase more than that of Campanula portenschlagiana when a low level of supplemental light is provided. Conversely, when ambient PPF >200 μmol·m−2·s−1, supplemental lighting will have little impact on An of H. americana, but can still results in significant increases in An of C. portenschlagiana (1.7 to 6.1 μmol·m−2·s−1 as supplemental PPF increases from 50 to 250 μmol·m−2·s−1). Adjusting the duty cycle of the LEDs based on PPF levels assures that supplemental light is provided when plants can use that supplemental light most efficiently. Implementing automated duty cycle control of LED grow lights is simple and low cost. This approach can increase the cost effectiveness of supplemental lighting, because of the associated energy savings.

scholarly journals Improving Winter Growth in the Citrus Nursery with LED and HPS Supplemental Lighting

HortScience ◽  
2021 ◽  
Vol 56 (1) ◽  
pp. 21-27
Author(s):  
Kim D. Bowman ◽  
Ute Albrecht
Keyword(s):  
Vegetative Growth ◽  
Light Emitting Diode ◽  
Specific Information ◽  
Stem Cuttings ◽  
Led Light ◽  
Citrus Rootstock ◽  
Nursery Production ◽  
Growth Initiation ◽  
Bud Growth ◽  
Supplemental Lighting

Modern citrus nursery production makes use of potted-tree propagation in greenhouses. Supplemental lighting is one method by which nursery tree growth and profitability may be significantly improved, but limited specific information is available. Five replicated experiments were conducted to determine the utility and effects of increasing daylength during the winter months by supplemental illumination from light-emitting diode (LED) or high-pressure sodium (HPS) lights in citrus nursery propagation. Studies used ‘Valencia’ sweet orange scion, the most common citrus cultivar grown in Florida, and the commercially important rootstocks sour orange, ‘Cleopatra’ mandarin, ‘US-812’, ‘US-897’, ‘US-942’, and ‘US-1516’. Comparisons used the three common types of citrus rootstock propagation: seed, stem cuttings, and micropropagation. Six responses were measured in the lighting experiments, including vegetative growth before budding, scion bud survival, and scion bud growth after budding. Supplemental HPS or LED light to extend daylength to 16 h in the citrus nursery during short-day winter months was observed to be effective in increasing unbudded rootstock liner growth and ‘Valencia’ scion growth on all rootstocks and propagation types. Generally, the positive effect on vegetative growth from an increased daylength was stronger with the HPS light than with LED light, while increasing daylength with LED light, but not HPS light, provided some increased bud growth initiation. Use of HPS or LED supplemental lighting to extend daylength offers significant growth advantage for the citrus nursery industry in winter.

scholarly journals Growth and Appearance Quality of Four Microgreen Species under Light-emitting Diode Lights with Different Spectral Combinations

HortScience ◽  
2020 ◽  
Vol 55 (9) ◽  
pp. 1399-1405
Author(s):  
Qinglu Ying ◽  
Yun Kong ◽  
Youbin Zheng
Keyword(s):  
Plant Height ◽  
High Intensity ◽  
Light Emitting Diode ◽  
Red Light ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Light Emitting ◽  
Led Light ◽  
Red Led ◽  
Dry Biomass

To investigate plant growth and quality responses to different light spectral combinations, cabbage (Brassica oleracea L. var. capitata f. rubra), kale (Brassica napus L. ‘Red Russian’), arugula (Eruca sativa L.), and mustard (Brassica juncea L. ‘Ruby steak’) microgreens were grown in a controlled environment using sole-source light with six different spectra: 1) FL: cool white fluorescent light; 2) BR: 15% blue and 85% red light-emitting diode (LED); 3) BRFRL: 15% blue, 85% red, and 15.5 µmol·m−2·s−1 far-red (FR) LED; 4) BRFRH: 15% blue, 85% red, and 155 µmol·m−2·s−1 FR LED; 5) BGLR: 9% blue, 6% green, and 85% red LED; and 6) BGHR: 5% blue, 10% green, and 85% red LED. For all the light treatments, the total photosynthetic photon flux density (PPFD) was set at ≈330 µmol·m−2·s−1 under a 17-hour photoperiod, and the air temperature was ≈21 °C with 73% relative humidity (RH). At harvest, BR vs. FL increased plant height for all the tested species except arugula, and enlarged cotyledon area for kale and arugula. Adding high-intensity FR light to blue and red light (i.e., BRFRH) further increased plant height for all species, and cotyledon area for mustard, but it did not affect the fresh or dry biomass for any species. Also, BRFRH vs. BR increased cotyledon greenness for green-leafed species (i.e., arugula, cabbage, and kale), and reduced cotyledon redness for red-leafed mustard. However, BGLR, BGHR, and BRFRL, compared with BR, did not affect plant height, cotyledon area, or fresh or dry biomass. These results suggest that the combination of 15% blue and 85% red LED light can potentially replace FL as the sole light source for indoor production of the tested microgreen species. Combining high-intensity FR light, rather than low-level (≤10%) green light, with blue and red light could be taken into consideration for the optimization of LED light spectral quality in microgreen production under environmental conditions similar to this experiment.

scholarly journals Design of a Secondary Freeform Lens of UV LED Mosquito-Trapping Lamp for Enhancing Trapping Efficiency

Crystals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 335 ◽  
Author(s):  
Wei-Hsiung Tseng ◽  
Diana Juan ◽  
Wei-Cheng Hsiao ◽  
Cheng-Han Chan ◽  
Hsin-Yi Ma ◽  
...  
Keyword(s):  
Light Intensity ◽  
Intensity Distribution ◽  
Light Emitting Diode ◽  
Trapping Efficiency ◽  
Axially Symmetric ◽  
Light Intensity Distribution ◽  
Light Emitting ◽  
Led Light ◽  
Uv Led ◽  
Freeform Lens

In this study, our proposed ultraviolet light-emitting diode (UV LED) mosquito-trapping lamp is designed to control diseases brought by insects such as mosquitoes. In order to enable the device to efficiently catch mosquitoes in a wider area, a secondary freeform lens (SFL) is designed for UV LED. The lens is mounted on a 3 W UV LED light bar as a mosquito-trapping lamp of the new UV LED light bar module to achieve axially symmetric light intensity distribution. The special SFL is used to enhance the trapping capabilities of the mosquito-trapping lamp. The results show that when the secondary freeform surface lens is applied to the experimental outdoor UV LED mosquito-trapping lamp, the trapping range can be expanded to 100π·m2 and the captured mosquitoes increased by about 300%.

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

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.

scholarly journals Different LED Light Wavelengths and Photosynthetic Photon Flux Density Effect on Colletotrichum acutatum Growth

Plants ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 143
Author(s):  
Neringa Rasiukevičiūtė ◽  
Aušra Brazaitytė ◽  
Viktorija Vaštakaitė-Kairienė ◽  
Alma Valiuškaitė
Keyword(s):  
Flux Density ◽  
Photosynthetic Photon Flux Density ◽  
Growth Characteristics ◽  
Colletotrichum Acutatum ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Photon Flux ◽  
Light Emitting ◽  
Led Light ◽  
Fungus Growth

The study aimed to evaluate the effect of different photon flux density (PFD) and light-emitting diodes (LED) wavelengths on strawberry Colletotrichum acutatum growth characteristics. The C. acutatum growth characteristics under the blue 450 nm (B), green 530 nm (G), red 660 nm (R), far-red 735 nm (FR), and white 5700 K (W) LEDs at PFD 50, 100 and 200 μmol m−2 s−1 were evaluated. The effect on C. acutatum mycelial growth evaluated by daily measuring until five days after inoculation (DAI). The presence of conidia and size (width and length) evaluated after 5 DAI. The results showed that the highest inhibition of fungus growth was achieved after 1 DAI under B and G at 50 μmol m−2 s−1 PFD. Additionally, after 1–4 DAI under B at 200 μmol m−2 s−1 PFD. The lowest conidia width was under FR at 50 μmol m−2 s−1 PFD and length under FR at 100 μmol m−2 s−1 PFD. Various LED light wavelengths influenced differences in C. acutatum colonies color. In conclusion, different photosynthetic photon flux densities and wavelengths influence C. acutatum growth characteristics. The changes in C. acutatum morphological and phenotypical characteristics could be related to its ability to spread and infect plant tissues. This study’s findings could potentially help to manage C. acutatum by LEDs in controlled environment conditions.

scholarly journals PERANCANGAN ALAT PENDETEKSI KELAYAKAN OLI PADA KENDARAAN SEPEDA MOTOR BERBASIS ARDUINO UNO ATMEGA328

SIGMA TEKNIKA ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 179
Author(s):  
Muhammad Iirsyam
Keyword(s):  
Light Emitting Diode ◽  
Motor Vehicles ◽  
Light Reflection ◽  
Oil Viscosity ◽  
Light Emitting ◽  
Led Light ◽  
Detection Tool ◽  
Arduino Uno ◽  
Resistance Value ◽  
Oil Color

 AbstrakPada kendaraan bermotor pelumasan adalah suatu hal yang sangat penting. Pelumasan berfungsi untuk melumasi komponen logam atau metal yang bergesekan dalam mesin. Untuk menjaga performa mesin kendaraan tetap prima maka kita harus cermat dalam memilih jenis oli yang akan digunakan menurut tingkat kekentalan oli yang dibutuhkan oleh kendaraan yang kita gunakan. Selain itu pemeriksaan dan pergantian oli secara berkala berperan penting dalam menjaga awetnya mesin kendaraan.Untuk membantu dalam pengecekan oli bagi para pemilik kendaran bermotor dalam hal ini sepeda motor dalam itu peneliti merancang sebuah alat pendeteksi kelayakan oli pada kendaraan sepeda motor. Perubahan nilai resistansi dari sensor IR (Infrared Resistor) setelah menerima pantulan cahaya dari LED (Light Emitting Diode) yang diletakkan diatas permukaan oli menyebabkan tegangan yang diterima Arduino Uno microcontroller ATmega328 membaca perubahan warna oli pada sebuah baki oli sepeda motor. Kata kunci : Pengecekan oli, Pantulan cahaya LED, Arduino Uno   AbstractLubrication in motor vehicles is important, lubrication is not only serves to lubricate metal or metal touching or friction in the machine. To maintain the performance of the vehicle's engine is prime, we must carefully select the type of oil to be used according to the oil viscosity level required by the vehicle we use. In addition, inspection and oil change periodically play an important role in maintaining the vehicle's crew.To assist in oil checking for motorised owners in this motorcycle in this case the author devised an oil feasibility detection tool on a motorcycle vehicle. Changes in resistance value from IR sensor (Infrared Resistor) after receiving light reflection from LED (Light Emitting Diode) that is placed above the oil surface causing the received voltage Arduino Uno Microcontroller ATmega328 Read the changes Oil color on a motorcycle oil tray. Keywords: Oil checking, LED light reflection, Arduino Uno

Sign in / Sign up

Export Citation Format

Share Document