scholarly journals 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 ◽  
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.

scholarly journals The Effect of Supplemental Blue, Red and Far-Red Light on the Growth and the Nutritional Quality of Red and Green Leaf Lettuce

2019 ◽  
Vol 10 (12) ◽  
pp. 2219-2235
Author(s):  
Myungjin Lee ◽  
Jingwen Xu ◽  
Weiqun Wang ◽  
C. B. Rajashekar
Keyword(s):  
Nutritional Quality ◽  
Red Light ◽  
Green Leaf ◽  
Leaf Lettuce

scholarly journals Improvement of the Growth and Nutritional Quality of Two-leaf-color Pak Choi by Supplemental Alternating Red and Blue Light

HortScience ◽  
2020 ◽  
pp. 1-8
Author(s):  
Jing Huang ◽  
Ya-liang Xu ◽  
Fa-min Duan ◽  
Xu Du ◽  
Qi-chang Yang ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Vitamin C ◽  
Blue Light ◽  
Nutritional Quality ◽  
Green Leaf ◽  
Carotenoid Content ◽  
Leaf Color ◽  
Time Intervals ◽  
Pak Choi

The aim of the present study was to evaluate the effects of alternating red (660 nm) and blue (460 nm) light on the growth and nutritional quality of two-leaf-color pak choi (Brassica campestris L. ssp. chinensis var. communis). Four light treatments (supplemental alternating red and blue light with intervals of 0, 1, 2, and 4 hours, with a monochromatic light intensity of 100 μmol·m−2·s−1 and a cumulative lighting time of 16 hours per day) were conducted in a greenhouse under identical ambient light conditions (90 to 120 μmol·m−2·s−1 at 12:00 am) for 10 days before green- and red-leaf pak choi were harvested. The results showed that the two-leaf-color pak choi receiving alternating red and blue light exhibited more compact canopies and wider leaves than those under the control treatment, which was attributed to the shade avoidance syndrome of plants. The present study indicated that the biomass of green-leaf pak choi was much higher than that of red-leaf pak choi, but the nutritional quality of green-leaf pak choi was lower than that of red-leaf pak choi, and seemingly indicating that the regulation of metabolism for pak choi was species specific under light exposure. The trends of both biomass and the soluble sugar content were highest under the 1-hour treatment. The contents of chlorophyll a and total chlorophyll in both cultivars (green- and red-leaf pak choi) were significantly increased compared with control, without significant differences among the 1-, 2-, and 4-hour treatments, whereas chlorophyll b exhibited no significant difference in any treatment. Alternating red- and blue-light treatment significantly affected the carotenoid content, but different trends in green- and red-leaf pak choi were observed, with the highest contents being detected under the 1-hour and 4-hour treatments, respectively. With increasing time intervals, the highest soluble protein contents in two-leaf-color pak choi were observed in the 4-hour treatment, whereas nitrate contents were significantly decreased in the 4-hour treatment. Compared with 0 hours, the contents of vitamin C, phenolic compounds, flavonoids, and anthocyanins in two-leaf-color pak choi were significantly increased, but no significant differences were observed in vitamin C, phenolic compounds, and flavonoids among the 1-, 2-, and 4-hour treatments, similar to what was found for the anthocyanin content of green-leaf pak choi. However, the content of anthocyanins in red-leaf pak choi gradually increased with increasing time intervals, with the highest content being found in the 4-hour treatment. Supplemental alternating red and blue light slightly increased the antioxidant capacity [1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging rate and antioxidant power], but no significant differences were observed after 1, 2, and 4 hours of treatment. Taken together, treatment with an interval of 1 hour was the most effective for increasing the biomass of pak choi in this study, but treatment with a 4-hour interval should be considered to enhance the accumulation of health-promoting compounds.

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

HortScience ◽  
2013 ◽  
Vol 48 (8) ◽  
pp. 988-995 ◽  
Author(s):  
Ki-Ho Son ◽  
Myung-Min Oh
Keyword(s):  
Phenolic Compounds ◽  
Leaf Shape ◽  
Leaf Length ◽  
Green Leaf ◽  
Total Phenolic ◽  
Light Emitting ◽  
Spad Value ◽  
Red Led ◽  
Leaf Lettuce ◽  
Phenolic Concentration

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.

scholarly journals Supplemental UV-A and UV-B Affect the Nutritional Quality of Lettuce and Tomato: Health-Promoting Phytochemicals and Essential Nutrients

2021 ◽  
Vol 12 (01) ◽  
pp. 104-126
Author(s):  
Myungjin Lee ◽  
Cary Rivard ◽  
Eleni Pliakoni ◽  
Weiqun Wang ◽  
C. B. Rajashekar
Keyword(s):  
Nutritional Quality ◽  
Essential Nutrients ◽  
Health Promoting

scholarly journals Effect of Light Characteristics on the Sensory Properties of Red Lettuce (Lactuca sativa)

Foods ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2660
Author(s):  
Kelly Gude ◽  
Martin Talavera ◽  
Audra M. Sasse ◽  
Cary L. Rivard ◽  
Eleni Pliakoni
Keyword(s):  
Open Field ◽  
Ultra Violet ◽  
Visual Quality ◽  
Color Intensity ◽  
Shade Cloth ◽  
High Tunnels ◽  
Green Production ◽  
Soil Temperatures ◽  
Leaf Lettuce ◽  
Effect Of Light

Leafy green production in high tunnels (HTs) results in increased yields, improved visual quality, and extended production with polyethylene (poly) film and/or shade cloth coverings. However, altering visible and ultra-violet light with HT coverings may reduce phytochemicals, thus influencing plant pigmentation and taste. The objective of this study was to examine various HT coverings on the sensory perceptions, soil temperature, color, and anthocyanin accumulation of red leaf lettuce. The coverings included standard poly, standard poly with removal two weeks prior to harvest (movable), diffuse poly, clear poly, UV-A/B blocking poly (block), standard poly with 55% shade cloth, and the open field. A highly trained descriptive panel evaluated the samples using a scale from 0 (none) to 15 (extremely high) and determined a list of 20 sensory attributes. The color intensity attribute had the most differentiation between coverings, and the open field was higher (i.e., darker) than the others at 7.5 (p < 0.0001), followed by clear and movable coverings at 6.8, and the shade covering scored a 2. Strong relationships existed between both colorimetric (hue°) and anthocyanin analysis to panelist-based scores (R2 = 0.847 and 0.640, respectively). The initial crispness was similar for movable, standard, diffuse, and block coverings at 5.3 on average, which was higher than the open field at 4 (p < 0.01). The open field lettuce grew under cooler soil temperatures, which may have slowed down maturation and resulted in softer tissue. Based on this study, HT growers can implement specific coverings to cater to markets that value visual quality.

scholarly journals Effect of Colored Shadecloth on the Quality and Yield of Lettuce and Snapdragon

2017 ◽  
Vol 27 (6) ◽  
pp. 860-867 ◽  
Author(s):  
Tongyin Li ◽  
Guihong Bi ◽  
Judson LeCompte ◽  
T. Casey Barickman ◽  
Bill B. Evans
Keyword(s):  
Phenolic Compounds ◽  
Transpiration Rate ◽  
Physiological Responses ◽  
Green Leaf ◽  
Light Spectrum ◽  
Growth Indices ◽  
Leaf Transpiration ◽  
Ornamental Crops ◽  
Delayed Flowering ◽  
Leaf Lettuce

Colored shadecloths are used in the production of vegetable, fruit, and ornamental crops to manipulate the light spectrum and to induce specific plant physiological responses. The influence of three colored shadecloths (red, blue, and black) with 50% shade and a no-shade control on the production of two lettuce (Lactuca sativa) cultivars [Two Star (green-leaf) and New Red Fire (red-leaf)] and snapdragon (Antirrhinum majus) was investigated. Use of shadecloth increased plant growth indices of lettuce and total length of snapdragon flower stems (at the first harvest) compared with no-shade control. Red shadecloth resulted in longer flower stems of snapdragon (at the second harvest) than black and blue shadecloths and no-shade control. However, shadecloth delayed blooming of snapdragon for 1 week compared with no-shade control. Stomatal conductance (gs) and leaf transpiration rate of both lettuce cultivars and photosynthetic rate and transpiration rate of snapdragon were decreased in response to shadecloth treatments. All shadecloths decreased health beneficial flavonoids (luteolin/quercetin glucuronide and quercetin malonyl concentrations for both lettuce cultivars and cyanidin glucoside in red-leaf lettuce). The two lettuce cultivars varied in their phenolic compounds, with the green-leaf ‘Two Star’ having higher quercetin glucoside and caftaric acid than red-leaf ‘New Red Fire’, whereas ‘New Red Fire’ had higher concentrations of chlorogenic acid, luteolin/quercetin glucuronide, and quercetin malonyl. Shadecloths reduced substrate temperature and photosynthetically active radiation (PAR) to about half of full sunlight compared with no-shade control, which may have contributed to reduced gs and leaf transpiration (for lettuce and snapdragon), decreased phenolic compounds in lettuce, and delayed flowering of snapdragon.

scholarly journals Impact of Shade and Fogging on High Tunnel Production and Mineral Content of Organically Grown Lettuce, Basil, and Arugula in Georgia

Agriculture ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 625
Author(s):  
Savanah Laur ◽  
Andre Luiz Biscaia Ribeiro da Silva ◽  
Juan Carlos Díaz-Pérez ◽  
Timothy Coolong
Keyword(s):  
Mineral Content ◽  
Planting Date ◽  
High Tunnel ◽  
Lactuca Sativa L ◽  
Air Temperatures ◽  
Shade Cloth ◽  
High Tunnels ◽  
Soil Temperatures ◽  
Organically Grown ◽  
The Impact

This study evaluated the impact of shade cloth and fogging systems on the microclimate at the plant canopy level and yield of basil (Oscimum basilicum L.), arugula (Eruca vesicaria subsp. Sativa L.), and lettuce (Lactuca sativa L.) planted in mid-September and early October in high tunnels. Fogging systems were installed at canopy level in plots within shaded (30%) and non-shaded high tunnels. Average air temperatures in the shaded high tunnels were 0.9 °C lower than non-shaded high tunnels during the day. Shade cloth significantly reduced soil temperatures during the day and night periods by 1.5 °C and 1.3 °C, respectively, compared to non-shaded treatments. Fogging systems did not have an impact on air temperature, soil temperature, or relative humidity, but did increase canopy leaf wetness. Shade and fogging did not impact the yield of any of the crops grown. Yield was impacted by planting date, with earlier planting result in higher yields of lettuce and basil. Yields for arugula were greater during the second planting date than the first. Planting date and shade cloth interacted to affect the concentrations of macronutrients.

scholarly journals Tea as a Source of Biologically Active Compounds in the Human Diet

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1487
Author(s):  
Joanna Klepacka ◽  
Elżbieta Tońska ◽  
Ryszard Rafałowski ◽  
Marta Czarnowska-Kujawska ◽  
Barbara Opara
Keyword(s):  
Antioxidant Activity ◽  
Phenolic Compounds ◽  
Daily Intake ◽  
The Body ◽  
Biologically Active ◽  
Sodium Potassium ◽  
Tea Infusions ◽  
Copper Manganese ◽  
Health Promoting ◽  
Average Consumption

Due to the different levels of bioactive compounds in tea reported in the literature, the aim of this study was to determine whether commercially available leaf teas could be an important source of phenolics and selected minerals (copper, manganese, iron, zinc, magnesium, calcium, sodium, potassium) and if the differences in the content of these components between various types of tea are significant. It was found that both the amount of these compounds in tea and the antioxidant activity of tea infusions were largely determined by the origin of tea leaves as well as the processing method, which can modify the content of the studied components up to several hundred-fold. The group of green teas was the best source of phenolic compounds (110.73 mg/100 mL) and magnesium (1885 µg/100 mL) and was also characterised by the highest antioxidant activity (59.02%). This type of tea is a great contributor to the daily intake of the studied components. The average consumption of green tea infusions, assumed to be 3–4 cups (1 L) a day, provides the body with health-promoting polyphenol levels significantly exceeding the recommended daily dose. Moreover, drinking one litre of an unfermented tea infusion provides more than three times the recommended daily intake of manganese. Tea infusions can be a fairly adequate, but only a supplementary, source of potassium, zinc, magnesium, and copper in the diet. Moreover, it could be concluded that the antioxidant activity of all the analysed types of tea infusions results not only from the high content of phenolic compounds and manganese but is also related to the presence of magnesium and potassium.

scholarly journals Optimization of extraction methods for characterization of phenolic compounds in apricot fruit (Prunus armeniaca)

2019 ◽  
Vol 10 (10) ◽  
pp. 6492-6502
Author(s):  
Lisard Iglesias-Carres ◽  
Anna Mas-Capdevila ◽  
Francisca Isabel Bravo ◽  
Cinta Bladé ◽  
Anna Arola-Arnal ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Extraction Methods ◽  
Prunus Armeniaca ◽  
Health Promoting

Fruits are rich in phenolic compounds with health-promoting activities.

scholarly journals Seasonal Variation of Health-Promoting Bioactives in Broccoli and Methyl-Jasmonate Pre-Harvest Treatments to Enhance Their Contents

Foods ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1371 ◽  
Author(s):  
Vanesa Nuñez-Gómez ◽  
Nieves Baenas ◽  
Inma Navarro-González ◽  
Javier García-Alonso ◽  
Diego A. Moreno ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Phenolic Compounds ◽  
Methyl Jasmonate ◽  
Bioactive Compounds ◽  
High Performance ◽  
Total Phenolic ◽  
Diode Array ◽  
Total Carotenoids ◽  
Health Promoting

Broccoli is a source of bioactive compounds that provide an important nutritional value. The content of these compounds can vary depending on agronomic and environmental conditions, as well as on elicitation. In this study, three crop trials were carried out to evaluate the effects of the cultivation season, the application of different dosages of methyl-jasmonate (MeJA) on the overall quality and on the total content of bioactive compounds of ‘Parthenon’ broccoli cultivated under the field conditions of southeastern Spain. Color parameters, chlorophyll content, total phenolic compounds, total flavonoids and antioxidant activity were measured to evaluate the overall quality. Moreover, individual carotenoids, phenolic compounds and glucosinolates were evaluated by high performance liquid chromatography with diode array detection (HPLC-DAD) and high performance liquid chromatography equipped with diode array detector coupled to mass spectrometer using electro spray ionization (HPLC-DAD-ESI/MSn). The content of total carotenoids, phenolic compounds and glucosinolates were higher in autumn compared with spring, showing increases of 2.8-fold, 2-fold and 1.2-fold, respectively. Moreover, a double application of MeJA increased the contents of total carotenoids, phenolic compounds and glucosinolates by 22%, 32% and 39%, respectively, relative to the untreated samples. Considering our results, the controlled and timely application of 250 µM MeJA to the aerial parts of the plants four days before harvest, on two consecutive days, seems to be a valid agronomic strategy to improve the health-promoting capacity of Parthenon broccoli, without compromising its overall quality.

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