scholarly journals Sprouting Broccoli Accumulate Higher Concentrations of Nutritionally Important Metabolites under Narrow-band Light-emitting Diode Lighting

2014 ◽  
Vol 139 (4) ◽  
pp. 469-477 ◽  
Author(s):  
Dean A. Kopsell ◽  
Carl E. Sams ◽  
T. Casey Barickman ◽  
Robert C. Morrow
Keyword(s):  
Blue Light ◽  
Nutritional Quality ◽  
Narrow Band ◽  
Light Treatment ◽  
Fluorescent Light ◽  
Total Carotenoids ◽  
Light Emitting ◽  
Incandescent Light ◽  
Red Led ◽  
The Impact

Previous research in our group demonstrated that short-duration exposure to narrow-band blue wavelengths of light can improve the nutritional quality of sprouting broccoli (Brassica oleacea var. italica) microgreens. The objective of this study was to measure the impact of different percentages of blue light on the concentrations of nutritional quality parameters of sprouting broccoli microgreens and to compare incandescent/fluorescent light with light-emitting diodes (LEDs). Microgreen seeds were cultured hydroponically on growing pads under light treatments of: 1) fluorescent/incandescent light; 2) 5% blue (442 to 452 nm)/95% red (622 to 632 nm); 3) 5% blue/85% red/10% green (525 to 535 nm); 4) 20% blue/80% red; and 5) 20% blue/70% red/10% green in controlled environments. Microgreens were grown at an air temperature of 24 °C and a 16-hour photoperiod using a light intensity of 250 μmol·m−2·s−1 for all light treatments. On emergence of the first true leaf, a nutrient solution of 42 mg·L−1 nitrogen (N) (20% Hoagland’s #2 solution) was used to submerge the growing pads. Microgreens were harvested after 20 days under the light treatments and shoot tissues were processed and measured for nutritionally important shoot pigments, glucosinolates, and mineral nutrients. Microgreens under the fluorescent/incandescent light treatment had significantly lower shoot fresh mass than plants under the 5% blue/95% red, 5% blue/85% red/10% green, and the 20% blue/80% red LED light treatments. The highest concentrations of shoot tissue chlorophyll, β-carotene, lutein, total carotenoids, calcium (Ca), magnesium (Mg), phosphorus (P), sulfur (S), boron (B), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), zinc (Zn), glucoiberin, glucoraphanin, 4-methoxyglucobrassicin, and neoglucobrassicin were found in microgreens grown under the 20% blue/80% red light treatment. In general, the fluorescent/incandescent light treatment resulted in significantly lower concentrations of most metabolites measured in the sprouting broccoli tissue. Results from the current study clearly support data from many previous reports that describe stimulation of primary and secondary metabolite biosynthesis by exposure to blue light wavelengths from LEDs.

scholarly journals The Proportion of Blue Light from Light-emitting Diodes Alters Microgreen Phytochemical Profiles in a Species-specific Manner

HortScience ◽  
2021 ◽  
Vol 56 (1) ◽  
pp. 13-20
Author(s):  
Qinglu Ying ◽  
Chase Jones-Baumgardt ◽  
Youbin Zheng ◽  
Gale Bozzo
Keyword(s):  
Blue Light ◽  
Light Emitting Diodes ◽  
Red Light ◽  
Total Carotenoids ◽  
Total Anthocyanin ◽  
Light Emitting ◽  
Red Cabbage ◽  
Species Specific ◽  
A Minor ◽  
The Impact

Microgreens are specialty vegetables that contain human health-promoting phytochemicals. Typically, microgreens are cultivated in controlled environments under red and blue light-emitting diodes (LEDs). However, the impact of varying the proportions of these light qualities on the composition of diverse phytochemicals in indoor-grown microgreens is unclear. To address this problem, the levels of chlorophylls, carotenoids, ascorbates, phenolics, anthocyanins, and nitrate were examined in arugula (Eruca sativa L.), ‘Red Russian’ kale [Brassica napus L. subsp. napus var. pabularia (DC.) Alef.], ‘Mizuna’ mustard (Brassica juncea L.), and red cabbage (Brassica oleracea L. var. capitata f. rubra) microgreens following cultivation under LEDs supplying varying proportions of blue light (5% to 30%) and red light (70% to 95%). Varying the proportion of blue light did not affect the extractable levels of total chlorophyll, total carotenoids, or nitrate in all four microgreen species. Generally, the levels of reduced and total ascorbate were greatest in arugula, kale, and mustard microgreens at 20% blue light, and a minor decrease was apparent at 30% blue light. These metabolite profiles were not impacted by the blue light percentage in red cabbage. Kale and mustard accumulated more total phenolics at 30% blue light than all other blue light regimens; however, this phytochemical attribute was unaffected in arugula and red cabbage. The total anthocyanin concentration increased proportionally with the percentage of supplied blue light up to 30% in all microgreens, with the exception of mustard. Our research showed that 20% blue light supplied from LED arrays is ideal for achieving optimal levels of both reduced and total ascorbate in all microgreens except red cabbage, and that 30% blue light promotes the greatest accumulation of total anthocyanin in indoor-grown Brassicaceae microgreens, with the exception of mustard.

Studies of Degradation in Nichia AlGaN/InGaN/GaN Blue Light Emitting Diodes Under Close to Normal Operating Conditions

1996 ◽  
Vol 421 ◽  
Author(s):  
M. Osiński ◽  
D. L. Barton ◽  
C. J. Helms ◽  
P. Perlin ◽  
N. H. Berg ◽  
...  
Keyword(s):  
Blue Light ◽  
Light Emitting Diodes ◽  
Defect Density ◽  
Degradation Process ◽  
Operating Conditions ◽  
Similar Amount ◽  
Life Testing ◽  
Light Emitting ◽  
High Pulsed Current ◽  
The Impact

AbstractThe reliability of devices fabricated in GaN and related alloys, especially under high current densities as would be found in lasers, has yet to be fully characterized. Our previous work [1] investigated the degradation of GaN-based blue light emitting diodes (LEDs) under high pulsed current stress. This work indicated a possible correlation between the high crystal defect density and failures caused by metal migration along these defect tubes. To assess the impact of this data on devices under more normal conditions, several LEDs from both older and more recent production lots were placed in a controlled temperature and current environment for several thousand hours. The test started with a constant 20 mA current for the first 1000 hours and continued for another 1650 hours at various currents up to 70 mA, all at a temperature of 23 °C. During this test, one of the older generation LED's output degraded by more than 50%. Subsequent failure analysis showed that this was caused by a crack which isolated part of the active region from the p-contact. The remaining LEDs were returned to life testing where the temperature was subsequently increased by 5 °C after each 500 hours of testing. The output from one of the newer LEDs dreiven at 70 mA degraded to 55% of its original value after 3600 hours and a second newer LED degraded by a similar amount after 4400 hours. The first failure, LED #16, did not exhibit a significant change in its I-V characteristics indicating that a change in the package transparency was a likely cause for the observed degradation. The second failure, LED #17, did show a noticeable change in its I-V characteristics. This device was subsequently returned to life testing where the degradation process will be monitored for further changes.

scholarly journals Effect of thidiazuron and monochromatic light on shoot development in vitro culture of Polygonum cuspidatum Sieb et Zucc

2020 ◽  
Vol 4 (2) ◽  
pp. First
Author(s):  
Doan Phan Phuong Thao ◽  
Tuan Anh Le ◽  
Phan Ngo Hoang
Keyword(s):  
Blue Light ◽  
Phenolic Content ◽  
Monochromatic Light ◽  
Total Phenolic ◽  
Fluorescent Light ◽  
Polygonum Cuspidatum ◽  
Blue Led ◽  
Red Led ◽  
Number Of Shoots

Polygonum cuspidatum Sieb. et Zucc, a medicinal plant, contains many phenolic compounds such as resveratrol. It has antioxidant, antibacterial, anti-cancer, HIV, and neuron protective properties. In this study, stem segments having an auxiliary bud were cultured in vitro on MS medium supplemented with TDZ at 0.1 mg/L for obtaining the highest number of shoots (8–9 shoots/cluster after eight weeks). The bud shoots were originated from the differentiation in the periphery of the lateral meristem. After eight weeks, the shoots cultured under the monochromatic light showed that the plant height, fresh and dry weight was higher than those grown under the fluorescent light at the same intensity of 50 µmol photon/m2/sec. Blue LED reduced the number of shoots/cluster, and respiration intensity of the inoculum compared to the red LED or fluorescent light conditions. However, after eight weeks, the total sugar and phenolic content in leaves and stems, as well as the resveratrol content of shoots under blue light, were always higher than under red LED or fluorescent light. Moreover, when samples were exposed under the one-week blue light condition at a double intensity (100 µmol photon/m2/sec), the shoot clusters growing under blue LED also had a remarkably high total phenolic content and significantly high resveratrol levels compared to the two other treatments. The roles of endogenous growth regulators in shoot clusters under different lighting conditions were also analyzed and discussed.

Narrow-band blue-light treatment of seasonal affective disorder in adults and the influence of additional nonseasonal symptoms

2009 ◽  
Vol 26 (3) ◽  
pp. 273-278 ◽  
Author(s):  
Robert E. Strong ◽  
Barrie K. Marchant ◽  
Frederick W. Reimherr ◽  
Erika Williams ◽  
Poonam Soni ◽  
...  
Keyword(s):  
Affective Disorder ◽  
Blue Light ◽  
Seasonal Affective Disorder ◽  
Narrow Band ◽  
Light Treatment

scholarly journals Far-red and Blue Light Synergistically Mitigate Intumescence Injury of Tomato Plants Grown Under Ultraviolet-deficit Light Environment

HortScience ◽  
2016 ◽  
Vol 51 (6) ◽  
pp. 712-719 ◽  
Author(s):  
Tomomi Eguchi ◽  
Ricardo Hernández ◽  
Chieri Kubota
Keyword(s):  
Blue Light ◽  
Stem Elongation ◽  
Light Treatment ◽  
Light Environment ◽  
Photon Flux ◽  
Physiological Disorder ◽  
Tomato Plants ◽  
Light Emitting ◽  
Number Of Leaves ◽  
Percent Number

Intumescence injury is an abiotic-stress-induced physiological disorder associated with abnormal cell enlargement and cell division. The symptom includes blister- or callus-like growths on leaves, which occur on sensitive cultivars of tomato when they are grown under ultraviolet (UV)-deficit light environment, such as light-emitting diodes (LEDs). Previous studies suggest that intumescence can be reduced by increasing far-red (FR) or blue light. In the present study, effects of end-of-day FR (EOD-FR) light and high blue photon flux (PF) ratio during the photoperiod on intumescence injury were examined using ‘Beaufort’ interspecific tomato rootstock seedlings (Solanum lycopersicum × Solanum habrochaites), a cultivar highly susceptible to intumescence injury. Our study showed that EOD-FR light treatment moderately suppressed intumescence injury. Using EOD-FR light treatment, the percent number of leaves exhibiting intumescences was reduced from 62.0–70.7% to 39.4–43.1%. By combining high blue PF ratio (75%) during the photoperiod and EOD-FR light treatment, the percent number of leaves exhibiting intumescences was further suppressed to 5.0%. Furthermore, the combination of high blue PF ratio and EOD-FR light treatment inhibited undesirable stem elongation caused by EOD-FR light treatment. We found that high blue PF ratio during the photoperiod combined with a small dose of EOD-FR lighting (≈1 mmol·m−2·d−1 provided by 5.2 µmol·m−2·s−1 FR PF for 3.3 minutes) could inhibit the problematic intumescence injury of tomato plants grown under LEDs without negatively influencing growth or morphology.

scholarly journals Increases in Shoot Tissue Pigments, Glucosinolates, and Mineral Elements in Sprouting Broccoli after Exposure to Short-duration Blue Light from Light Emitting Diodes

2013 ◽  
Vol 138 (1) ◽  
pp. 31-37 ◽  
Author(s):  
Dean A. Kopsell ◽  
Carl E. Sams
Keyword(s):  
Blue Light ◽  
Short Duration ◽  
Light Emitting Diodes ◽  
Mineral Elements ◽  
Light Emitting ◽  
Blue Led ◽  
Led Light ◽  
Shoot Tissue ◽  
Phytochemical Compounds ◽  
The Impact

Microgreens are specialty leafy crops harvested just above the roots after the first true leaves have emerged and are consumed fresh. Broccoli (Brassica oleacea var. italica) microgreens can accumulate significant concentrations of cancer-fighting glucosinolates as well as being a rich source of other antioxidant phytochemicals. Light-emitting diodes (LEDs) now provide the ability to measure impacts of narrow-band wavelengths of light on seedling physiology. The carotenoid zeaxanthin has been hypothesized to be a blue light receptor in plant physiology. The objective of this study was to measure the impact of short-duration blue light on phytochemical compounds, which impart the nutritional quality of sprouting broccoli microgreens. Broccoli microgreens were grown in a controlled environment under LEDs using growing pads. Seeds were cultured on the pads submerged in deionized water and grown under a 24-hour photoperiod using red (627 nm)/blue (470 nm) LEDs (350 μmol·m−2·s−1) at an air temperature of 23 °C. On emergence of the first true leaf, a complete nutrient solution with 42 mg·L−1 of nitrogen (N) was used to submerge the growing pads. At 13 days after sowing, broccoli plantlets were grown under either: 1) red and blue LED light (350 μmol·m−2·s−1); or 2) blue LED light (41 μmol·m−2·s−1) treatments for 5 days before harvest. The experiment was repeated three times. Frozen shoot tissues were freeze-dried and measured for carotenoids, chlorophylls, glucosinolates, and mineral elements. Comparing the two LED light treatments revealed the short-duration blue LED treatment before harvest significantly increased shoot tissue β-carotene (P ≤ 0.05), violaxanthin (P ≤ 0.01), total xanthophyll cycle pigments (P ≤ 0.05), glucoraphanin (P ≤ 0.05), epiprogoitrin (P ≤ 0.05), aliphatic glucosinolates (P ≤ 0.05), essential micronutrients of copper (Cu) (P = 0.02), iron (Fe) (P ≤ 0.01), boron (B), manganese (Mn), molybdenum (Mo), sodium (Na), zinc (Zn) (P ≤ 0.001), and the essential macronutrients of calcium (Ca), phosphorus (P), potassium (K), magnesium (Mg), and sulfur (S) (P ≤ 0.001). Results demonstrate management of LED lighting technology through preharvest, short-duration blue light acted to increase important phytochemical compounds influencing the nutritional value of broccoli microgreens.

scholarly journals Pulsed LED Light: Exploring the Balance between Energy Use and Nutraceutical Properties in Indoor-Grown Lettuce

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1106
Author(s):  
Laura Carotti ◽  
Giulia Potente ◽  
Giuseppina Pennisi ◽  
Karina B. Ruiz ◽  
Stefania Biondi ◽  
...  
Keyword(s):  
Energy Use ◽  
Fluorescent Light ◽  
Switching Frequency ◽  
Resource Use Efficiency ◽  
Light Emitting ◽  
Use Efficiency ◽  
Lighting Systems ◽  
Qualitative Responses ◽  
The Impact ◽  
Nutraceutical Properties

In indoor vertical farms, energy consumption represents a bottleneck for both a system’s affordability and environmental footprint. Although switching frequency (sf) represents a crucial factor in determining the efficacy of light emitting diodes (LED) lighting systems in converting electricity into light, the impact of sf is still underexplored. The aim of this work was to investigate the effect of LEDs sf on the productive and qualitative responses of lettuce (Lactuca sativa L.), also considering the resource use efficiency. Plants were grown for 14 days under red and blue LEDs (215 μmol m−2 s−1 and 16/8 h light/dark, with a red:blue ratio of 3) characterized by two different sf for the blue diode, namely high sf (850 kHz) and low sf (293 kHz). A fluorescent light (same light intensity and photoperiod) was included. LED sf did not alter plant morphological parameters, including fresh or dry biomass, leaf number, leaf area, or water use efficiency. A low sf increased the energy use efficiency (EUE) by 40% as compared to high sf. The latter enhanced the leaf antioxidant capacity, as a consequence of increased concentrations of caftaric and chicoric acids, isoquercetin, and luteolin, consistent with the upregulation of a few genes related to the biosynthetic pathway of phenolic compounds (4C3H and DFR). The study highlights that different sf may significantly affect the EUE as well as crop nutritional properties.

scholarly journals Effect of alternating red and blue light irradiation generated by light emitting diodes on the growth of leaf lettuce

2014 ◽  
Author(s):  
Akihiro Shimokawa ◽  
Yuki Tonooka ◽  
Misato Matsumoto ◽  
Hironori Ara ◽  
Hiroshi Suzuki ◽  
...  
Keyword(s):  
Plant Growth ◽  
Blue Light ◽  
Global Climate ◽  
Light Condition ◽  
Light Irradiation ◽  
Fluorescent Light ◽  
Promoting Effect ◽  
Light Emitting ◽  
Simultaneous Irradiation ◽  
Leaf Lettuce

Because global climate change has made agricultural supply unstable, plant factories are expected to be a safe and stable means of food production. As the light source of a plant factory or controlled greenhouse, the light emitting diode (LED) is expected to solve cost problems and promote plant growth efficiently. In this study, we examined the light condition created by using monochromatic red and blue LEDs, to provide both simultaneous and alternating irradiation to leaf lettuce. The result was that simultaneous red and blue irradiation promoted plant growth more effectively than monochromatic and fluorescent light irradiation. Moreover, alternating red and blue light accelerated plant growth significantly even when the total light intensity per day was the same as with simultaneous irradiation. The fresh weight in altering irradiation was almost two times higher than with fluorescent light and about 1.6 times higher than with simultaneous irradiation. The growth-promoting effect of alternating irradiation of red and blue light was observed in different cultivars. From the results of experiments, we offer a novel plant growth method named "Shigyo Method", the core concept of which is the alternating irradiation of red and blue light.

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