Leaf Shape, Growth, and Antioxidant Phenolic Compounds of Two Lettuce Cultivars Grown under Various Combinations of Blue and Red Light-emitting Diodes

Light-emitting diodes (LEDs) of short wavelength ranges are being developed as light sources in closed-type plant production systems. Among the various wavelengths, red and blue lights are known to be effective for enhancing plant photosynthesis. In this study, we determined the effects of blue and red LED ratios on leaf shape, plant growth, and the accumulation of antioxidant phenolic compounds of a red leaf lettuce (Lactuca sativa L. ‘Sunmang’) and a green leaf lettuce (Lactuca sativa L. ‘Grand Rapid TBR’). Lettuce seedlings grown under normal growth conditions (20 °C, fluorescent lamp + high-pressure sodium lamp 177 ± 5 μmol·m−2·s−1, 12-hour photoperiod) for 18 days were transferred into growth chambers that were set at 20 °C and equipped with various combinations of blue (456 nm) and red (655 nm) LEDs [blue:red = 0:100 (0 B), 13:87 (13 B), 26:74 (26 B), 35:65 (35 B), 47:53 (47 B) or 59:41 (59 B)] under the same light intensity and photoperiod (171 ± 7 μmol·m−2·s−1, 12-hour photoperiod). Leaf width, leaf length, leaf area, fresh and dry weights of shoots and roots, chlorophyll content (SPAD value), total phenolic concentration, total flavonoid concentration, and antioxidant capacity were measured at 2 and 4 weeks after the onset of LED treatment. The leaf shape indices (leaf length/leaf width) of the two lettuce cultivars subjected to blue LEDs treatment were similar to the control, regardless of the blue-to-red ratio during the entire growth stage. However, 0 B (100% red LED) induced a significantly higher leaf shape index, which represents elongated leaf shape, compared with the other treatments. Increasing blue LED levels negatively affected lettuce growth. Most growth characteristics (such as the fresh and dry weights of shoots and leaf area) were highest under 0 B for both cultivars compared with all other LED treatments. For red and green leaf lettuce cultivar plants, shoot fresh weight under 0 B was 4.3 and 4.1 times higher compared with that under 59 B after 4 weeks of LED treatment, respectively. In contrast, the accumulation of chlorophyll, phenolics (including flavonoids), and antioxidants in both red and green leaf lettuce showed an opposite trend compared with that observed for growth. The SPAD value (chlorophyll content), total phenolic concentration, total flavonoid concentration, and antioxidant capacity of lettuces grown under high ratios of blue LED (such as 59 B, 47 B, and 35 B) were significantly higher compared with 0 B or control conditions. Thus, this study indicates that the ratio of blue to red LEDs is important for the morphology, growth, and phenolic compounds with antioxidant properties in the two lettuce cultivars tested.

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Effects of Light-Emitting Diodes on the Accumulation of Phenolic Compounds and Glucosinolates in Brassica juncea Sprouts

Horticulturae ◽

10.3390/horticulturae6040077 ◽

2020 ◽

Vol 6 (4) ◽

pp. 77

Author(s):

Chang Ha Park ◽

Ye Eun Park ◽

Hyeon Ji Yeo ◽

Jae Kwang Kim ◽

Sang Un Park

Keyword(s):

Phenolic Compounds ◽

Chlorogenic Acid ◽

Brassica Juncea ◽

Light Treatment ◽

Total Phenolic ◽

White Led ◽

Light Emitting ◽

Blue Led ◽

Led Light ◽

Red Led

Recent improvements in light-emitting diode (LED) technology afford an excellent opportunity to investigate the relationship between different light sources and plant metabolites. Accordingly, the goal of the present study was to determine the effect of different LED (white, blue, and red) treatments on the contents of glucosinolates (glucoiberin, gluconapin, sinigrin, gluconasturtiin, 4-methoxyglucobrassicin, 4-hydroxyglucobrassicin, glucobrassicin, and neoglucobrassicin) and phenolic compounds (4-hydroxybenzonate, catechin, chlorogenic acid, caffeate, gallate, sinapate, and quercetin) in Brassica juncea sprouts. The sprouts were grown in a growth chamber at 25 °C under irradiation with white, blue, or red LED with a flux rate of 90 μmol·m−2·s−1 and a long-day photoperiod (16 h light/8 h dark cycle). Marked differences in desulfoglucosinolate contents were observed in response to treatment with different LEDs and different treatment durations. In addition, the highest total desulfoglucosinolate content was observed in response to white LED light treatment, followed by treatment with red LED light, and then blue LED light. Among the individual desulfoglucosinolates identified in the sprouts, sinigrin exhibited the highest content, which was observed after three weeks of white LED light treatment. The highest total phenolic contents were recorded after one week of white and blue LED light treatment, whereas blue LED irradiation increased the production of most of the phenolic compounds identified, including 4-hydroxybenzonate, gallate, sinapate, caffeate, quercetin, and chlorogenic acid. The production of phenolics decreased gradually with increasing duration of LED light treatment, whereas anthocyanin accumulation showed a progressive increase during the treatment. These findings indicate that white LED light is appropriate for glucosinolate accumulation, whereas blue LED light is effective in increasing the production of phenolic compounds in B. juncea sprouts.

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Effect of Light-Emitting Diodes on the Mycelial Biomass Production and Antioxidant Activity of Ganoderma lucidum (W. Curt.: Fr.) P. Karst.

CLSU International Journal of Science and Technology ◽

10.22137/ijst.2021.v5n1.01 ◽

2021 ◽

Vol 5 (1) ◽

pp. 1-10

Author(s):

Abegail Alcazar ◽

◽

Rich Milton Dulay ◽

Sofronio Kalaw ◽

Renato Reyes ◽

...

Keyword(s):

Biomass Production ◽

Ganoderma Lucidum ◽

Phenolic Content ◽

Radical Scavenging Activity ◽

Radical Scavenging ◽

Total Phenolic ◽

Mycelial Biomass ◽

Light Emitting ◽

Colony Diameter ◽

Red Led

Light is an important factor for the growth of many forms of life, including mushrooms. This paper highlights the effects of the different wavelengths (red, 650 nm; blue, 450 nm; green, 525 nm) of light emitting diodes (LEDs) on the growth, biomass production and antioxidant properties of Ganoderma lucidum. G. lucidum is a white-rot, wood-degrading fungus in the Basiodiomycota that typically grows on logs. Mycelia were grown on coconut water agar (CWA) solid media for analysis of mycelial colony diameter as well as coconut water (CW) submerged culture for analysis of mycelial biomass weight. Both set-ups were incubated in variously-colored LED chambers. The DPPH radical scavenging activity and total phenolic content of the harvested mycelia were also determined. After three days of incubation, G. lucidum mycelia under red LED recorded the highest mean mycelial colony diameter of 72.50 mm. In terms of mycelia biomass production, G. lucidum mycelia exposed in red LED and dark produced the heaviest weight. On the other hand, mycelia grown under green LED had the highest radical scavenging activity of 66.49% while those harvested from red LED showed the highest total phenolic content of 81.29 mg GAE / g of sample. Our results demonstrate that LED color influences the mycelial growth, biomass production and antioxidant activities of G. lucidum.

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Effects of Light-Emitting Diodes on the Accumulation of Glucosinolates and Phenolic Compounds in Sprouting Canola (Brassica napus L.)

Foods ◽

10.3390/foods8020076 ◽

2019 ◽

Vol 8 (2) ◽

pp. 76 ◽

Cited By ~ 7

Author(s):

Chang Park ◽

Nam Kim ◽

Jong Park ◽

Sook Lee ◽

Jong-Won Lee ◽

...

Keyword(s):

Brassica Napus ◽

Phenolic Compounds ◽

Light Emitting Diode ◽

Red Light ◽

Dry Weight ◽

Total Phenolic ◽

Brassica Napus L ◽

Light Emitting ◽

Led Light ◽

Sprout Growth

In this study, we investigated optimal light conditions for enhancement of the growth and accumulation of glucosinolates and phenolics in the sprouts of canola (Brassica napus L.). We found that the shoot lengths and fresh weights of red light-irradiated sprouts were higher than those of sprouts exposed to white, blue, and blue + red light, whereas root length was not notably different among red, blue, white, and blue + red light treatments. The accumulations of total glucosinolates in plants irradiated with white, blue, and red lights were not significantly different (19.32 ± 0.13, 20.69 ± 0.05, and 20.65 ± 1.70 mg/g dry weight (wt.), respectively). However, sprouts exposed to blue + red light contained the lowest levels of total glucosinolates (17.08 ± 0.28 mg/g dry wt.). The accumulation of total phenolic compounds was the highest in plants irradiated with blue light (3.81 ± 0.08 mg/g dry wt.), 1.33 times higher than the lowest level in plants irradiated with red light (2.87 ± 0.05 mg/g dry wt.). These results demonstrate that red light-emitting diode (LED) light is suitable for sprout growth and that blue LED light is effective in increasing the accumulation of glucosinolates and phenolics in B. napus sprouts.

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Spectral Blocking of Solar Radiation in High Tunnels by Poly Covers: Its Impact on Nutritional Quality Regarding Essential Nutrients and Health-Promoting Phytochemicals in Lettuce and Tomato

Horticulturae ◽

10.3390/horticulturae7120524 ◽

2021 ◽

Vol 7 (12) ◽

pp. 524

Author(s):

Myungjin Lee ◽

Cary Rivard ◽

Weiqun Wang ◽

Eleni Pliakoni ◽

Kelly Gude ◽

...

Keyword(s):

Phenolic Compounds ◽

Solar Radiation ◽

Nutritional Quality ◽

Spectral Characteristics ◽

Green Leaf ◽

Essential Nutrients ◽

Shade Cloth ◽

High Tunnels ◽

Health Promoting ◽

Leaf Lettuce

Spectral characteristics of solar radiation have a major role in plant growth and development and the overall metabolism, including secondary metabolism, which is important for the accumulation of health-promoting phytochemicals in plants. The primary focus of this study was to determine the effect of spectral characteristics of solar radiation on the nutritional quality of lettuce (Lactuca sativa L., cv. red leaf ‘New Red Fire’ and green leaf ‘Two Star’ and tomato (Solanum lycopersicum L., cv. BHN-589) grown in high tunnels in relation to the accumulation of essential nutrients and phytochemicals. Solar spectrum received by crops was modified using photo-selective poly covers. Treatments included commonly used standard poly, luminescence poly (diffuse poly), clear poly, UV blocking poly, exposure of crops grown under the standard poly to full sun 2 weeks prior to harvest (akin to movable tunnel), and 55% shade cloth on the standard poly. All the poly covers and shade cloth reduced the PAR levels in the high tunnels, and the largest reduction was by the shade cloth, which reduced the solar PAR by approximately 48%. Clear poly allowed the maximum UV-A and UV-B radiation, while standard poly allowed only a small fraction of the solar UV-A and UV-B (between 15.8% and 16.2%). Clear poly, which allowed a higher percentage of solar UV-A (60.5%) and UV-B (65%) than other poly covers, increased the total phenolic concentration and the antioxidant capacity in red leaf lettuce. It also increased the accumulation of flavonoids, including quercetin-3-glucoside, luteolin-7-glucoside, and apigenin-3-glucoside in red leaf lettuce, compared to the standard poly. Brief exposure of crops grown in high tunnels to full sun prior to harvest produced the largest increase in the accumulation of quercetin-3-glucoside, and it also resulted in an increase in luteolin-7-glucoside and apigenin-3-glucoside in red leaf lettuce. Thus, clear poly and brief exposure of red leaf lettuce to the full sun, which can increase UV exposure to the plants, produced a positive impact on its nutritional quality. In contrast, shade cloth which allowed the lowest levels of solar PAR, UV-A and UV-B relative to the other poly covers had a negative impact on the accumulation of the phenolic compounds in red leaf lettuce. However, in green leaf lettuce, luminesce poly, clear poly, UV-block poly, and shade treatments increased the accumulation of many essential nutrients, including protein, magnesium, and sulfur in green leaf lettuce compared to the standard poly. Poly cover treatments including shade treatment did not affect the accumulation of either carotenoids (lutein, β-carotene, and lycopene) or essential nutrients in mature tomato fruits. The results show that clear poly cover can enhance the accumulation of many phenolic compounds in red leaf lettuce, as does the brief exposure of the crop to the full sun prior to harvest. Thus, UV radiation plays an important role in the accumulation of phenolic compounds in red leaf lettuce while the overall spectral quality of solar radiation has a significant influence on the accumulation of essential nutrients in green leaf lettuce.

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Light Intensity and Light Quality from Sole-source Light-emitting Diodes Impact Phytochemical Concentrations within Brassica Microgreens

Journal of the American Society for Horticultural Science ◽

10.21273/jashs03830-16 ◽

2017 ◽

Vol 142 (1) ◽

pp. 3-12 ◽

Cited By ~ 17

Author(s):

Joshua K. Craver ◽

Joshua R. Gerovac ◽

Roberto G. Lopez ◽

Dean A. Kopsell

Keyword(s):

Light Intensity ◽

Light Quality ◽

Light Emitting Diodes ◽

Sole Source ◽

Photon Flux ◽

Total Phenolic ◽

Light Emitting ◽

Phytochemical Content ◽

Light Intensities ◽

Phenolic Concentration

Multilayer vertical production systems using sole-source (SS) light-emitting diodes (LEDs) can be an alternative to more traditional methods of microgreens production. One significant benefit of using LEDs is the ability to select light qualities that have beneficial impacts on plant morphology and the synthesis of health-promoting phytochemicals. Therefore, the objective of this study was to quantify the impacts of SS LEDs of different light qualities and intensities on the phytochemical content of brassica (Brassica sp.) microgreens. Specifically, phytochemical measurements included 1) total anthocyanins, 2) total and individual carotenoids, 3) total and individual chlorophylls, and 4) total phenolics. Kohlrabi (Brassica oleracea var. gongylodes), mustard (Brassica juncea ‘Garnet Giant’), and mizuna (Brassica rapa var. japonica) were grown in hydroponic tray systems placed on multilayer shelves in a walk-in growth chamber. A daily light integral (DLI) of 6, 12, or 18 mol·m−2·d−1 was achieved from SS LED arrays with light ratios (percent) of red:blue 87:13 (R87:B13), red:far-red:blue 84:7:9 (R84:FR7:B9), or red:green:blue 74:18:8 (R74:G18:B8) with a total photon flux from 400 to 800 nm of 105, 210, or 315 µmol·m−2·s–1 for 16 hours, respectively. Phytochemical measurements were collected using spectrophotometry and high-performance liquid chromatography (HPLC). Regardless of light quality, total carotenoids were significantly lower under increasing light intensities for mizuna and mustard microgreens. In addition, light quality affected total integrated chlorophyll with higher values observed under the light ratio of R87:B13 compared with R84:FR7:B9 and R74:G18:B8 for kohlrabi and mustard microgreens, respectively. For kohlrabi, with increasing light intensities, the total concentration of anthocyanins was greater compared with those grown under lower light intensities. In addition, for kohlrabi, the light ratios of R87:B13 or R84:FR7:B9 produced significantly higher anthocyanin concentrations compared with the light ratio of R74:G18:B8 under a light intensity of 315 µmol·m−2·s−1. Light quality also influenced the total phenolic concentration of kohlrabi microgreens, with significantly greater levels for the light ratio of R84:FR7:B9 compared with R74:G18:B8 under a light intensity of 105 µmol·m−2·s−1. However, the impact of light intensity on total phenolic concentration of kohlrabi was not significant. The results from this study provide further insight into the selection of light qualities and intensities using SS LEDs to achieve preferred phytochemical content of brassica microgreens.

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Supplementary Far-Red and Blue Lights Influence the Biomass and Phytochemical Profiles of Two Lettuce Cultivars in Plant Factory

Molecules ◽

10.3390/molecules26237405 ◽

2021 ◽

Vol 26 (23) ◽

pp. 7405

Author(s):

Yamin Li ◽

Linyuan Wu ◽

Haozhao Jiang ◽

Rui He ◽

Shiwei Song ◽

...

Keyword(s):

Phenolic Compounds ◽

Vitamin C ◽

Chlorophyll A ◽

Photon Flux ◽

Total Phenolic ◽

Total Flavonoids ◽

Total Phenolic Compounds ◽

Leaf Color ◽

Plant Factory ◽

Leaf Lettuce

Three different LED spectra (W: White light; WFR: W + far-red light; WB: W + blue light) with similar photosynthetic photon flux density (PPFD) were designed to explore the effects of supplementary far-red and blue lights on leaf color, biomass and phytochemicals of two cultivars of red-leaf lettuce (“Yanzhi” and “Red Butter”) in an artificial lighting plant factory. Lettuce plants under WB had redder leaf color and significantly higher contents of pigments, such as chlorophyll a, chlorophyll b, chlorophyll (a + b) and anthocyanins. The accumulation of health-promoting compounds, such as vitamin C, vitamin A, total phenolic compounds, total flavonoids and anthocyanins in the two lettuce cultivars were obviously enhanced by WB. Lettuce under WFR showed remarkable increase in fresh weight and dry weight; meanwhile, significant decreases of pigments, total phenolic compounds, total flavonoids and vitamin C were found. Thus, in the plant factory system, the application of WB can improve the coloration and quality of red leaf lettuce while WFR was encouraged for the purpose of elevating the yield of lettuce.

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Solar radiation affects bloat potential of wheat forage

Acta Agrobotanica ◽

10.5586/aa.1754 ◽

2018 ◽

Vol 71 (4) ◽

Author(s):

Dariusz Piotr Malinowski ◽

William E. Pinchak ◽

Dipti Pitta ◽

Byeng R. Min

Keyword(s):

Phenolic Compounds ◽

Solar Radiation ◽

Radiation Intensity ◽

Wheat Plant ◽

Total Phenolic ◽

Weather Patterns ◽

Growing Seasons ◽

Solar Radiation Intensity ◽

Short Term Exposure ◽

Phenolic Concentration

Frothy bloat is a serious digestive disorder in cattle (<em>Bos taurus</em> L.) grazing winter wheat (<em>Triticum aestivum</em> L.) pastures in the Southern Great Plains of the USA. Wheat plant metabolism may be one of the factors involved in bloat occurrence. In a series of experiments conducted during 2004–2007, we evaluated the effects of solar radiation intensity (ambient, 100% vs. reduced, 25%), a short-time (24 h vs. 48 h) exposure to solar radiation, and forage allowance (high, 18 kg vs. low, 6 kg DM/100 kg body weight) on seasonal concentration of phenolic compounds and foam strength (a measure of bloat potential) of wheat forage ‘Cutter’. Reduced solar radiation decreased total phenolic concentration and increased foam strength when compared to ambient solar radiation. Forage allowance interacted with solar radiation and short-term exposure treatments in determining phenolic concentrations; however, the effects were inconsistent during and among growing seasons. Concentration of phenolic compounds responded rapidly to sudden changes in weather patterns (passing cold fronts) that were usually associated with significant decrease in solar radiation intensity and temperature. Solar radiation intensity was positively correlated with total phenolic concentration and explained 62% to 72% of the variation in total phenolic concentration. Correlation between temperature and total phenolic concentration varied among growing seasons and explained 9–17% of the variation in total phenolic concentration. Results suggest that phenolic concentration in wheat forage is correlated with solar radiation. The decrease in phenolic concentration and resulting increase of bloat potential are especially pronounced during sudden changes in weather patterns during winter.

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Effect of Color Light Emitting Diode on the Mycelial Growth and Antioxidant Activity of Ganoderma lucidum in Solid and Submerged Culture

CLSU International Journal of Science and Technology ◽

10.22137/ijst.2021.v4n1.01 ◽

2021 ◽

Vol 5 (1) ◽

pp. 1-10

Author(s):

Abegail Alcazar ◽

Rich Milton R. Dulay ◽

Sofronio Kalaw ◽

Renato Reyes

Keyword(s):

Biomass Production ◽

Ganoderma Lucidum ◽

Submerged Culture ◽

Phenolic Content ◽

Radical Scavenging Activity ◽

Radical Scavenging ◽

Total Phenolic ◽

Light Emitting ◽

Colony Diameter ◽

Red Led

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Physicochemical and sensory analysis of common sorrel (Rumex acetosa L.)

REVISTA BRASILEIRA DE AGROTECNOLOGIA ◽

10.18378/rebagro.v12i2.8798 ◽

2021 ◽

Vol 11 (2) ◽

pp. 462-468

Author(s):

Maria Angélica Suedan Souza Lima ◽

Carolina Medeiros Vicentini-Polette ◽

Marta Helena Fillet Spoto ◽

Marta Regina Verruma-Bernardi ◽

Anastácia Fontanetti

Keyword(s):

Ascorbic Acid ◽

Phenolic Compounds ◽

Purchase Intention ◽

Leaf Shape ◽

Ascorbic Acid Content ◽

Sensory Attributes ◽

Total Phenolic ◽

Acceptance Test ◽

Grape Skin ◽

Instrumental Color

Common sorrel is a non-conventional vegetable of the family Polygonaceae, naturalized in Brazil and still with few nutritional and sensory studies. The aim of this work was to evaluate the physicochemical and sensory characteristics of Common sorrel, harvested at 60 days. Common sorrel was evaluated regarding the ascorbic acid content, total phenolic compounds, instrumental color: Luminosity (L*), chroma, Hue and chlorophyll. To describe the profile of the sensory attributes, 14 evaluators were used, and 52 for the acceptance test and purchase intention. Common sorrel presented 10.25 mg/100 g-1 of ascorbic acid, 290.51 mg / 100 g-1 of total phenolics and in the instrumental analysis of color, it presented L*, chroma and Hue of 49.28, 25.24 and 122.5, respectively. For chlorophyll index, 36.60 SPAD was observed. The sensory attributes described for Common sorrel using structured scale of 9 cm were: green coloration (4.6) and irregular leaf shape (4.3), aroma of grape skin (5.1), sour and bitter tastes (5.1 and 5.4 respectively), smooth texture (5.7), very thin leaf (3.3), soft texture (5.5) and flexible leaf (6.9). It was verified that Common sorrel obtained scores between 6 (liked very much) and 7 (loved it) for the acceptance of color, flavor, texture and global acceptance of the leaf. Regarding aroma, 32.7% of the scores were inferior to 4. Regarding purchase intention, 65.4% of the evaluators answered that they would certainly buy this vegetable. Although little known, this vegetable was well-accepted by the evaluators, demonstrating the potential for consumption. Key words: Acceptance; Color; Phenolic compounds; PANC.

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