scholarly journals Physiological, Morphological, and Energy-use Efficiency Comparisons of LED and HPS Supplemental Lighting for Cucumber Transplant Production

HortScience ◽  
2015 ◽  
Vol 50 (3) ◽  
pp. 351-357 ◽  
Author(s):  
Ricardo Hernández ◽  
Chieri Kubota
Keyword(s):  
Plant Growth ◽  
Energy Use ◽  
Growth Parameters ◽  
Dry Mass ◽  
Photon Flux ◽  
Peak Wavelength ◽  
Hypocotyl Length ◽  
Blue Led ◽  
Red Led ◽  
Greenhouse Growers

To increase the available photosynthetic photon flux (PPF) for plant growth, greenhouse growers sometimes use electric lighting to supplement solar light. The conventional lighting technology used to increase PPF in the greenhouse is high-pressure sodium lamps (HPS). A potential alternative to HPS is high-intensity light-emitting diodes (LEDs). The objective of this study is to compare supplemental LED lighting with supplemental HPS lighting in terms of plant growth and morphology as well as discuss the energy use efficiencies of the fixtures. There were three light treatments: 1) blue LED (peak wavelength 443 nm); 2) red LED (peak wavelength 633 nm); and 3) HPS, to provide 3.7 ± 0.2 mol·m−2·d−1 (background solar radiation of 6.3 ± 0.9 mol·m−2·d−1). Cucumber (Cucumis sativus) plants at the transplanting stage (26 to 37 days) under HPS had 28% greater dry mass than did plants under the LED treatments. This can be attributed to the higher leaf temperature under the HPS treatment. No differences were observed in growth parameters (dry mass, fresh weight, or number of leaves) between the blue and red LED treatments. Plants under the blue LED treatment had greater net photosynthetic rate and stomatal conductance (gS) than those under the red LED and HPS treatments. Plants under the blue LED and HPS treatments had 46% and 61% greater hypocotyl length than those under the red LED, respectively. The fixture PPF efficiencies used in the experiment were 1.9, 1.7, and 1.64 μmol·J−1 for the blue LED, red LED, and HPS treatments, respectively; however, the fixture growing efficiency (g·kWh−1) of HPS was 6% and 17% greater than the blue LED and red LED treatment, respectively. In summary, supplemental red LED produced desirable plant compactness and HPS had greater fixture growing efficiency than LEDs.

scholarly journals Effect of Different Ratios of Blue and Red LED Light on Brassicaceae Microgreens under a Controlled Environment

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 801
Author(s):  
Aušra Brazaitytė ◽  
Jurga Miliauskienė ◽  
Viktorija Vaštakaitė-Kairienė ◽  
Rūta Sutulienė ◽  
Kristina Laužikė ◽  
...  
Keyword(s):  
Nutritional Value ◽  
Growth Parameters ◽  
Light Emitting Diode ◽  
Dry Mass ◽  
Mineral Nutrients ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Controlled Environment ◽  
Red Led ◽  
Positive Effect

The consumption of microgreens has increased due to their having higher levels of bioactive compounds and mineral nutrients than mature plants. The lighting conditions during the cultivation of microgreens, if optimally selected, can have a positive effect by further increasing their nutritional value. Thus, our study aimed to determine the changes in mineral nutrients contents of Brassicaceae microgreens depending on different blue–red (B:R) light ratios in light-emitting diode (LED) lighting and to evaluate their growth and nutritional value according to different indexes. Experiments were performed in controlled environment growth chambers at IH LRCAF, 2020. Microgreens of mustard (Brassica juncea ‘Red Lace’) and kale (Brassica napus ‘Red Russian’) were grown hydroponically under different B:R light ratios: 0%B:100%R, 10%B:90%R, 25%B:75%R, 50%B:50%R, 75%B:25%R, and 100%B:0%R. A 220 μmol m−2 s−1 total photon flux density (TPFD), 18 h photoperiod, 21/17 ± 2 °C temperature and 60% ± 5% relative humidity in the growth chamber were maintained during cultivation. We observed that an increasing percentage of blue light in the LED illumination spectrum during growth was associated with reduced elongation in the microgreens of both species and had a positive effect on the accumulation of mostly macro- and micronutrients. However, different B:R light ratios indicate a species-dependent response to changes in growth parameters such as leaf area, fresh and dry mass, and optical leaf indexes such as for chlorophyll, flavonol, anthocyanin, and carotenoid reflectance.

scholarly journals Application of Chondroitin Sulfate on Organogenesis of Two Cymbidium spp. under Different Sources of Lights

2016 ◽  
Vol 8 (2) ◽  
pp. 156-160 ◽  
Author(s):  
Syeda Jabun NAHAR ◽  
Syed M. HAQUE ◽  
Shimasaki KAZUHIKO
Keyword(s):  
Plant Growth ◽  
Chondroitin Sulfate ◽  
Growth Regulator ◽  
Plant Growth Regulator ◽  
Ms Medium ◽  
Food Ingredients ◽  
Blue Led ◽  
Red Led ◽  
Green Led ◽  
Modified Ms Medium

The aim of this study was to present chondroitin sulfate as a plant growth regulator and to give an overview about light effects on PLBs (protocorm like bodies) culture of Cymbidium dayanum and Cymbidium finlaysonianum cultured in vitro. Chondroitin sulfate is a sulfated glycosaminoglycan (GAG) composed of a chain of alternating sugars N-acetylgalactosamine and glucuronic acid. It is widely used as a material for food ingredients, cosmetics and medicine. PLBs were cultured on modified MS medium containing different concentration of chondroitin sulfate (0, 0.1, 1 and 10 mg/l), under four sources of lights: conventional white fluorescent tube, red LED, green LED and blue LED. In C. dayanum, 100% PLBs formation rate was observed at 0.1 mg/l chondroitin sulfate with modified MS medium under green LED and 1 mg/l chondroitin sulfate under blue LED; the maximum shoots and roots formation were observed under green LEDs (93% and 80% respectively) when media contained 0.1 mg/l chondroitin sulfate. In C. finlaysonianum, every concentrations of chondroitin sulfate enhanced the growth rate of PLBs when compared to control treatment, under all four sources of lights. The highest values were recorded with 0.1 mg/l chondroitin sulfate which induced 100% PLBs formation under blue LED, while 10 mg/l chondroitin sulfate had induced 100% PLBs formation under green LED. The highest percentage of shoots (73%) was initiated in the medium containing 10 mg/l chondroitin sulfate under green LED. Plant development was strongly influenced by the light quality and plant growth regulator functions as chemical messengers for intercellular communication of plant. The results demonstrated that low concentrations of chondroitin sulfate could promote PLBs, shoots and roots formation of Cymbidium spp. under green and blue LED.

scholarly journals Growth and Energy Use Efficiency of Grafted Tomato Transplants as Affected by LED Light Quality and Photon Flux Density

Agriculture ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 816
Author(s):  
Jianfeng Zheng ◽  
Peidian Gan ◽  
Fang Ji ◽  
Dongxian He ◽  
Po Yang
Keyword(s):  
Energy Use ◽  
Light Quality ◽  
Red Light ◽  
Electrical Energy ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Red Led ◽  
Use Efficiency ◽  
Led Lights

This study was conducted to compare the effects of broad spectrum during the whole seedling period and photon flux density (PFD) in the healing stage on the growth and energy use efficiency of grafted tomato (Lycopersicon esculentum Mill.) transplants in a plant factory. Fluorescent lights, white LED lights, and white plus red LED lights were applied at the growth processes of grafted tomato transplants from germination of rootstock and scion to post-grafting. Three levels of PFD (50, 100, 150 μmol m−2 s−1) were set in the healing stage under each kind of light quality. The results indicated that the growth and quality of grafted tomato transplants under different broad spectrums were influenced by the ratio of red to blue light (R/B ratio) and the ratio of red to far-red light (R/FR ratio). A higher R/B ratio was beneficial to total dry matter accumulation, but excessive red light had a negative effect on the root to shoot ratio and the seedling quality index. The higher blue light and R/FR ratio suppressed stem extension synergistically. The LED lights had good abilities to promote plant compactness and leaf thickness in comparison with fluorescent lights. The plant compactness and leaf thickness increased with the increase in daily light integral in the healing stage within a range from 2.5 to 7.5 mol m−2 d−1 (PFD, 50 to 150 μmol m−2 s−1). Compared to fluorescent lights, the LED lights showed more than 110% electrical energy saving for lighting during the whole seedling period. Higher PFD in the healing stage did not significantly increase the consumption of electric power for lighting. White plus red LED lights with an R/B ratio of 1.2 and R/FR ratio of 16 were suggested to replace fluorescent lights for grafted tomato transplants production considering the high quality of transplants and electrical energy saving, and PFD in the healing stage was recommended to be set to 150 μmol m−2 s−1.

scholarly journals Photosynthetic Photon Flux, Photoperiod, and CO2 Concentration Affect Growth and Morphology of Lettuce Plug Transplants

HortScience ◽  
1998 ◽  
Vol 33 (6) ◽  
pp. 988-991 ◽  
Author(s):  
Yoshiaki Kitaya ◽  
Genhua Niu ◽  
Toyoki Kozai ◽  
Maki Ohashi
Keyword(s):  
Leaf Area ◽  
Specific Leaf Area ◽  
Dry Mass ◽  
Leaf Length ◽  
Leaf Number ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
Hypocotyl Length ◽  
R Ratio ◽  
Four Levels

Lettuce (Lactuca sativa L. cv. Summer-green) plug transplants were grown for 3 weeks under 16 combinations of four levels (100, 150, 200, and 300 μmol·m-2·s-1) of photosynthetic photon flux (PPF), two photoperiods (16 and 24 h), and two levels of CO2 (400 and 800 μmol·mol-1) in growth chambers maintained at an air temperature of 20 ±2 °C. As PPF increased, dry mass (DM), percent DM, and leaf number increased, while ratio of shoot to root dry mass (S/R), ratio of leaf length to leaf width (LL/LW), specific leaf area, and hypocotyl length decreased. At the same PPF, DM was increased by 25% to 100% and 10% to 100% with extended photoperiod and elevated CO2 concentration, respectively. Dry mass, percent DM, and leaf number increased linearly with daily light integral (DLI, the product of PPF and photoperiod), while S/R, specific leaf area, LL/LW and hypocotyl length decreased as DLI increased under each CO2 concentration. Hypocotyl length was influenced by PPF and photoperiod, but not by CO2 concentration. Leaf morphology, which can be reflected by LL/LW, was substantially influenced by PPF at 100 to 200 μmol·m-2·s-1, but not at 200 to 300 μmol·m-2·s-1. At the same DLI, the longer photoperiod promoted growth under the low CO2 concentration, but not under the high CO2 concentration. Longer photoperiod and/or higher CO2 concentration compensated for a low PPF.

scholarly journals Longer Photoperiods with Adaptive Lighting Control Can Improve Growth of Greenhouse-grown ‘Little Gem’ Lettuce (Lactuca sativa)

HortScience ◽  
2020 ◽  
Vol 55 (4) ◽  
pp. 573-580 ◽  
Author(s):  
Geoffrey Weaver ◽  
Marc W. van Iersel
Keyword(s):  
Lactuca Sativa ◽  
Energy Use ◽  
Control Strategies ◽  
Leaf Size ◽  
Dry Weight ◽  
Photon Flux ◽  
Lighting Control ◽  
Content Index ◽  
Supplemental Lighting ◽  
Greenhouse Growers

Supplemental lighting can improve the growth of greenhouse crops, but the electricity required for supplemental lighting can be a significant expense for greenhouse growers. Lighting control strategies that use the dimmability of light-emitting diodes (LEDs) have the potential to decrease this cost. In our experiments, we tested the hypothesis that providing ‘Little Gem’ lettuce (Lactuca sativa) plants with the same daily amount of light, spread out over a longer photoperiod and at lower average photosynthetic photon flux densities (PPFDs), would improve growth because light is used more efficiently to drive photosynthesis at lower PPFDs. We conducted two greenhouse experiments wherein supplemental light was provided to reach a minimum daily light integral (DLI) of 17 mol·m−2·d−1 with a 12, 15, 18, or 21-hour photoperiod using adaptive lighting control of LED lights. As the photoperiod for supplemental lighting was increased and supplemental light was provided at lower average PPFDs, plant dry weight increased. Conversion efficiency, the estimated increase in dry weight per Joule expended on supplemental lighting, increased as the photoperiod was extended from 12 to 21 hours. Leaf size and chlorophyll content index increased with longer photoperiods. The number of plants with symptoms of tipburn, including apical and marginal necrosis, also increased as the photoperiod was extended. These results demonstrate that adaptive lighting control can be used to increase the growth of ‘Little Gem’ lettuce and the energy use efficiency of supplemental lighting by providing supplemental light at relatively low PPFDs.

scholarly journals Salinity stress and plant growth regulator in basil: effects on plant and soil

DYNA ◽  
2021 ◽  
Vol 88 (217) ◽  
pp. 75-83
Author(s):  
Leonardo Vieira de Sousa ◽  
Toshik Iarley da Silva ◽  
Maria de Fátima de Queiroz Lopes ◽  
Márcia Paloma da Silva Leal ◽  
Ana Gabriela Sousa Basilio ◽  
...  
Keyword(s):  
Plant Growth ◽  
Growth Regulator ◽  
Plant Growth Regulator ◽  
Growth Parameters ◽  
Saline Water ◽  
Block Design ◽  
Dry Mass ◽  
Shoot Height ◽  
Randomized Block Design ◽  
The Matrix

The water in semiarid regions contains salts in excess. When good quality water is not available it is necessary to use strategies that can make feasible the use of saline water. The aim of this study was to evaluate the effects of the application of the plant growth regulator on the culture of basil stressed with salt. The experiment was carried out in a randomized block design by the matrix “Central Box Compound”. Shoot height, stem diameter, leaf area, dry masses and soil chemical characteristics were evaluated. The salinity of the irrigation water causes reduction of the basil growth parameters, with the exception of the inflorescence dry mass. Plant growth regulator applications have effect on basil growth when plants are irrigated with saline water.

scholarly journals Potential Use of Colored LED Lights to Increase the Production of Bioactive Metabolites Hedyotis corymbosa (L.) Lam

Plants ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 225
Author(s):  
Anh Tuan Le ◽  
Ju-Kyung Yu ◽  
Gyung-Deok Han ◽  
Thuong Kiet Do ◽  
Yong-Suk Chung
Keyword(s):  
Plant Growth ◽  
Crop Production ◽  
Genetically Modified Organisms ◽  
Light Emitting Diode ◽  
Photosynthetic Characteristics ◽  
Bioactive Metabolites ◽  
Total Phenolic ◽  
Blue Led ◽  
Red Led ◽  
Led Lights

Hedyotis corymbosa (L.) Lam is a wild herb that is used in traditional Indian, Chinese, and African medicine. Light-emitting diode (LED) technology is paving the way to enhance crop production and inducing targeted photomorphogenic, biochemical, or physiological responses in plants. This study examines the efficiency of H. corymbosa (L.) Lam production under blue 450 nm and red 660 nm LED lights for overall plant growth, photosynthetic characteristics, and the contents of metabolite compounds. Our research showed that blue LED lights provided a positive effect on enhancing plant growth and overall biomass. In addition, blue LED lights are more effective in controlling the production of sucrose, starch, total phenolic compounds, and total flavonoid compared to red LED lights. However, blue and red LED lights played essential but different roles in photosynthetic characteristics. Our results showed the potential of colored LED light applications in improving farming methods and increasing metabolite production in herbs. LED lights are safer alternatives than genetically modified organisms or genome editing.

scholarly journals Light Intensity and Fertilizer Concentration: I. Estimating Optimal Fertilizer Concentrations from Water-use Efficiency of Wax Begonia

HortScience ◽  
2004 ◽  
Vol 39 (6) ◽  
pp. 1287-1292 ◽  
Author(s):  
Krishna S. Nemali ◽  
Marc W. van Iersel
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Growth Parameters ◽  
Interactive Effect ◽  
Dry Mass ◽  
Photon Flux ◽  
Target Tissue ◽  
Starter Fertilizer ◽  
Growing Medium ◽  
Use Efficiency

Environmental conditions and incorporation of nutrients into the growing medium can affect the fertilizer needs of bedding plants. To evaluate the effects of photosynthetic photon flux (PPF) and starter fertilizer on the fertilizer requirements of subirrigated plants, we grew wax begonias (Begonia semperflorens-cultorum Hort.) under three PPF levels (averaging 4.4, 6.2, and 9.9 mol·m-2·d-1) and four fertilizer concentrations [electrical conductivity (EC) of 0.15, 0.33, 0.86, and 1.4 dS·m-1] in a normal (with starter fertilizer, EC = 2.1 dS·m-1) and heavily leached (with little starter fertilizer, EC = 0.9 dS·m-1) growing medium. Except for shoot dry mass, we did not find any significant interactions between PPF and fertilizer concentration on any of the growth parameters. There was an interactive effect of fertilizer concentration and starter fertilizer on all growth parameters (shoot dry mass, leaf area, plant height, and number of flowers). When the growing medium contained a starter fertilizer, fertilizer concentration had little effect on growth. When the growing medium was leached before transplanting, growth was best with a fertilizer EC of 0.86 or 1.4 dS·m-1. Water-use efficiency (WUE) was calculated from 24-hour carbon exchange and evapotranspiration measurements, and used to estimate the required [N] in the fertilizer solution to achieve a target tissue N concentration of 45 mg·g-1. Increasing PPF increased WUE and the required [N] (from 157 to 203 mg·L-1 at PPF levels of 4.4 and 9.9 mol·m-2·d-1, respectively). The PPF effect on the required [N] appeared to be too small to be of practical significance, since dry mass data did not confirm that plants grown at high light needed higher fertilizer concentrations. Thus, fertilizer concentrations need not be adjusted based on PPF.

scholarly journals Different Microgreen Genotypes Have Unique Growth and Yield Responses to Intensity of Supplemental PAR from Light-emitting Diodes during Winter Greenhouse Production in Southern Ontario, Canada

HortScience ◽  
2020 ◽  
Vol 55 (2) ◽  
pp. 156-163 ◽  
Author(s):  
Chase Jones-Baumgardt ◽  
David Llewellyn ◽  
Youbin Zheng
Keyword(s):  
Leaf Area ◽  
Growth And Yield ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Limiting Factor ◽  
Hypocotyl Length ◽  
Marketable Yield ◽  
Greenhouse Production ◽  
Light Emitting ◽  
Greenhouse Growers

Low natural daily light integrals (DLIs) are a major limiting factor for greenhouse production during darker months (e.g., October to February in Canada). Supplemental lighting (SL) is commonly used to maintain crop productivity and quality during these periods, particularly when the supply chain demands consistent production levels year-round. What remains to be determined are the optimum SL light intensities (LIs) for winter production of a myriad of different commodities. The present study investigated the growth and yield of sunflower (Helianthus annuus L., ‘Black oil’), kale (Brassica napus L., ‘Red Russian’), arugula (Eruca sativa L.), and mustard (Brassica juncea L., ‘Ruby Streaks’), grown as microgreens, in a greenhouse under SL light-emitting diode (LED) photosynthetic photon flux density (PPFD) levels ranging from 17.0 to 304 μmol·m−2·s−1 with a 16-hour photoperiod (i.e., supplemental DLIs from 1.0 to 17.5 mol·m−2·d−1). Crops were sown in a commercial greenhouse near Hamilton, ON, Canada (lat. 43°14′N, long. 80°07′W) on 1 Feb. 2018, and harvested after 8, 11, 12, and 12 days, resulting in average natural DLIs of 6.5, 5.9, 6.2, and 6.2 mol·m−2·d−1 for sunflower, kale, arugula, and mustard, respectively. Corresponding total light integrals (TLIs) ranged from 60 to 188 mol·m−2 for sunflower, 76 to 258 mol·m−2 for kale, 86 to 280 mol·m−2 for arugula, and 86 to 284 mol·m−2 for mustard. Fresh weight (i.e., marketable yield) increased asymptotically with increasing LI and leaf area increased linearly with increasing LI, in all genotypes. Hypocotyl length of mustard decreased and hypocotyl diameter of sunflower, arugula, and mustard increased with increasing LI. Dry weight, robust index, and relative chlorophyll content increased and specific leaf area decreased in kale, arugula, and mustard with increasing LI. Commercial microgreen greenhouse growers can use the light response models described herein to predict relevant production metrics according to the available (natural and supplemental) light levels to select the most appropriate SL LI to achieve the desired production goals as economically as possible.

scholarly journals Longer Photoperiods with the Same Daily Light Integral Improve Growth of Rudbeckia Seedlings in a Greenhouse

HortScience ◽  
2020 ◽  
Vol 55 (10) ◽  
pp. 1676-1682 ◽  
Author(s):  
Claudia Elkins ◽  
Marc W. van Iersel
Keyword(s):  
Leaf Area ◽  
Specific Leaf Area ◽  
Growth Parameters ◽  
Light Emitting Diode ◽  
Dry Mass ◽  
Photon Flux ◽  
Shade Avoidance ◽  
Daily Light Integral ◽  
Content Index ◽  
Light Integral

Supplemental light can increase growth and accelerate production of greenhouse crops, but it can be expensive if not provided in a way that promotes efficient use of the light. Dimmable light-emitting diode (LED) fixtures have the potential to reduce lighting costs because the output can be precisely controlled to meet crop needs. Because light is used more efficiently to drive photosynthesis at lower photosynthetic photon flux densities (PPFDs), we hypothesized that providing Rudbeckia fulgida var. sullivantii ‘Goldsturm’ seedlings with the same daily light integral (DLI), spread out over a longer photoperiod and at lower PPFDs, should improve growth. A DLI of 12 mol·m−2·d−1 was provided in a greenhouse over 12, 15, 18, or 21-hour photoperiods from a combination of sunlight and supplemental light from LEDs, using adaptive lighting control. Plants grown without supplemental light had an ≈12-hour photoperiod and received an average DLI of 5 mol·m−2·d−1, ≈58% less light than the four lighting treatments. Lengthening the photoperiod from 12 to 21 hours increased shoot dry mass (30%), root dry mass (24%), plant height (14%), leaf area (16%), and chlorophyll content index (48%), and decreased specific leaf area (26%). There was no significant effect of photoperiod on root mass fraction or compactness. Growth parameters of plants without supplemental light were 26% to 90% smaller compared with those in the 12-hour photoperiod treatment. Treatment effects on canopy size, seen as early as 2 weeks into the study, were correlated with final shoot dry mass. Longer photoperiods did not induce a shade-avoidance response, based on specific leaf area and compactness data. The 24% increase in root dry mass for the plants in the 21-hour photoperiod suggests that cropping cycles can be shortened by 1 to 2 weeks compared with the 12-hour photoperiod. This could result in more crop turns per year and increased profits. In addition, fewer lights would be needed for adequate growth, reducing the capital cost of the lighting system.

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