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LED lighting and seasonality effects antioxidant properties of baby leaf lettuce
Abstract
We report on the application of supplementary light-emitting diode (LED) lighting within a greenhouse for cultivation of red, green and light green leaf baby lettuces (Lactuca sativa L.) grown under natural illumination and high-pressure sodium (HPS) lamps (16-h; PPFD-170 μmol m−2 s−1) during different growing season. Supplementary lighting from blue 455/470 nm and green 505/530 nm LEDs was applied (16-h; PPFD-30 μmol m−2 s−1). Our results showed that to achieve solely a positive effect is complicated, because metabolism of antioxidant properties in lettuce depended on multicomponent exposure of variety, light quality or seasonality. The general trend of a greater positive effect of supplemental LED components on the vitamin C and tocopherol contents was in order: 535 > 505 > 455 > 470 nm; on the total phenol content: 505 > 535 = 470 > 455 nm; on the DPPH free-radical scavenging capacity: 535 = 470 > 505 > 455 nm; on the total anthocyanins: 505 > 455 > 470 > 535 nm. Further investigations are needed for understanding the mechanism and interaction between antioxidants and light signal transduction pathways.
... According to Li and Kubota (2009), the phenolic content of baby leaf lettuce increased by 6% with supplemental R compared to those in the light control. Samuolienė et al. (2012a) found a higher content of total phenols in baby lettuce leaves supplemented with green LED light with peaks at 505 and 535 nm than blue LED light. On the other hand, the highest antioxidant capacity was found for the green light (peak at 535 nm) and the blue light (peak at 470 nm). ...
... As many authors mentioned, spectrum light variation could enhance the health-promoting benefits of lettuce (Samuolienė et al., 2012a;2012b;Bian et al., 2014). Nevertheless, studies on supplementing ambient light with LED lighting in various seasons' lettuce growth are limited. ...
... Specifically, it was 62.6% higher in early and late winter than in autumn for 'Multibaby' and 61.6% to 70.2% for 'Thumper' in early and late winter, respectively. Regarding antioxidant capacity, Samuolienė et al. (2012a) observed a contradictory effect of supplemental blue and green LED lighting on the antioxidant properties of red, green, and green light varieties of baby leaf lettuce during the cultivation time of the year. Precisely, the antioxidant capacity of green lettuce and light green lettuce was higher in autumn and full winter than in late winter. ...
The light spectrum plays a major role in regulating plant growth and development, influencing photosynthesis and photo-morphogenesis. The objective was to evaluate the weight and antioxidant activity of ‘Lavinia’ lettuce (Lactuca sativa L. var. capitata L.) plants under LED lights with different red:blue ratios (R:B) used as a supplement to ambient light in a greenhouse at different seasons. Five LED light supplemented treatments were used, white (W, as control, ratio blue:green:red:far-red (B:G:R:Fr) = 30:45:20:5; 0.7:1.0), blue (B = 50:20:20:10; R:B = 0.4:1.0), white-r (Wr = 25:30:40:5; 1.6:1.0), white-R (WR = 15:15:63:7; 4.2:1.0) and red (R = 10:10:75:5; 7.5:1.0) were applied in early autumn, late autumn and winter. Immediately after transplant into the hydroponic system, lettuces plants with 3-4 true leaves (5-6 cm root length) were treated with light treatments for 14 d and harvested. In early autumn, late autumn, and winter, the PAR range applied in ambient light and supplemental lights was between 361 to 495, 222 to 304, and 297 to 407 µmol m-2 s-1, respectively. Lettuce showed the highest fresh leaf mass in early autumn compared to late autumn and winter due to the highest leaf number. In early autumn, only lettuce under the highest R:B (7.5:1.0) had a lower weight among the light treatments. Overall, lettuces supplemented with R:B between 1.6 (Wr) to 4.2 (WR) had significantly higher DM than the control (0.7:1.0). Total phenolic contents (TPC) and antioxidant capacity (AC) were highest in early autumn, followed by winter and late autumn. Light with the highest R:B (7.5:1.0) diminished TPC and AC in all growing season. This study showed that the quality of ‘Lavinia’ lettuce plants grown in early autumn under R:B between 1.6 and 4.2 improved DM, and higher red component decreased the antioxidant activity.
... Commonly utilised additional light for greenhouses is metal halide and fluorescent lighting. Research has shown that exposure to light improve the shelf-life and visual quality of microgreens such as spinach, radish and lettuce (23,24). However, mixed spectrum light ratios at various ratios have been adopted recently and found to improve LED lighting efficiency. ...
... After 2 days of green LED treatment with broccoli florets, total phenolic content increased to 40.4 % and 29.6 % more than those in control and fluorescent (400-700 nm) treated broccoli florets (11). Vitamin C and total phenol content were increased in baby leaf lettuce in green LED light (505 or 535 nm) than in blue LED light (455 or 470 nm) LED light (23). The okra treated with blue and white LED lights of 630 nm for 8 hours with an intensity of 17.28 Wm -2 had the highest total phenolic content. ...
Improper handling practices often aggravate post-harvest losses in horticultural produce. Due to ethylene production, climacteric fruits have a short shelf life, which triggers ripening and senescence. Traditionally, post-harvest preservation has relied on chemical methods, which can pose health risks. In contrast, Light-Emitting Diode (LED) treatment has emerged as an effective, residue-free alternative to conventional light sources for maintaining the quality of fruits and vegetables during storage. LED treatment has enhanced the accumulation of important phytochemicals such as vitamins, chlorophyll, total soluble solids and carotenoids in fruits and vegetables. It also leads to changes in anthocyanin, carotenoids, phenols and flavonoids. These beneficial effects are linked to the interaction of LED light with plant physiology, which can help regulate ripening, improve nutritional content and control microbial growth. Combining different LED wavelengths at varying intensities during post-harvest storage has been found to promote fresh produces’ nutritional value, slow` ripening and reduce pathogenic microbial load. While research on using LEDs for post-harvest quality preservation is still in its early stages, initial findings are promising. This review examines the applications of LED treatment in preserving the post-harvest quality of fresh horticultural produce, highlighting its role in extending shelf life, maintaining nutritional value and reducing post-harvest losses.
... When plants photosynthesize, they prefer medium-wavelength beams of blue, yellow, and red. These contribute to the formation of chlorophyll, the development of tissues, and blossoming (Taiz and Zeiger, 2008;Hogewoning et al., 2010;Samuolienė et al., 2012). Chlorophyll is the foundation of growth by using inorganic chemicals and generating organic substances (Samuolienė et al., 2012). ...
... These contribute to the formation of chlorophyll, the development of tissues, and blossoming (Taiz and Zeiger, 2008;Hogewoning et al., 2010;Samuolienė et al., 2012). Chlorophyll is the foundation of growth by using inorganic chemicals and generating organic substances (Samuolienė et al., 2012). Light is a critical signal that induces plastid development and carotenoid biosynthesis in plants. ...
Global population growth increases the need for efficient methods of maintaining a stable food supply. Light is one of the most important influences on plant growth and development. Artificial lighting elements used in agricultural applications have different effects on plants. This study analyzed the effects of metal halide (MH) lamps with a wavelength of 450 nm, at distances of 1, 1.5, and 2.5 m, on barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) growth. Growing occurred in light magnification rooms without daylight, using 250, 400, and 600 W MH lamps as the only light source. Plants exposed to light for 13–14 h a day were harvested after 18 days. After harvest, the amount of electrolyte leakage, chlorophyll, carotenoid, and B, Cu, Mn, Zn, K, and Ca intake were determined using inductively coupled plasma optical emission spectroscopy (ICP-OES). The data were analyzed with the SPSS 22 Statistical Package program. Wheat and barley grown at different light distances and intensities showed statistically significant changes in mineral element uptake and plant chlorophyll levels. This research contributes to the optimization of agricultural productivity and the understanding of the interaction between light quality and other environmental parameters.
... 17 In addition, LED lights have produced antioxidant properties in various crops, such as pea seedlings, spinach, lettuce, and komatsuna. 18 According to Yeo et al., LED arrays increase the accumulation of secondary metabolites including carotenoids, flavonoids, glucosinolates, and phenolic acids. 19 It is easier and more effective to control and evaluate the effects of light intensity on the biosynthesis of the desired substances. ...
... Thus, the combination of red and blue LEDs enhanced the production of these secondary metabolites. 18,19,34 In our study, the highest glucosinolate levels were found in the leaves exposed to red and red + blue LED lights (2937.81 ± 216.65 μg/g dw). ...
Pakchoi (Brassica rapa subsp. chinensis) is one of the most widely consumed vegetables in Asian countries, and it is high in secondary metabolites. The availability, quantity, and quality of light play a critical role in the growth and development of plants. In this study, we investigated the effect of LEDs (light-emitting diodes; white, blue, red, and red + blue) on anthocyanin, glucosinolates, and phenolic levels in red pakchoi baby leaves. On the 24th day after sowing (DAS), red baby pakchoi leaves were harvested, and shoot length, root length, and fresh weight were measured. Among the different LED treatments, there was no significant difference in shoot length, whereas the highest root length was achieved in the red + blue LED treatment (23.8 cm). The fresh weight also showed a significant difference among the different LED treatments. In total, 12 phenolic and 7 glucosinolate individual compounds were identified using high-performance liquid chromatography (HPLC) analysis. The highest total glucosinolate (2937 μg/g dry wt) and phenolic (1589 μg/g dry wt) contents were achieved in baby leaves exposed to red + blue light. Similarly, the highest contents of total anthocyanins (1726 μg/g dry wt), flavonoids (4920 μg/g dry wt), and phenolics (5900 μg/g dry wt) were achieved in the red + blue treatment. Plants exposed to red + blue LED light showed the highest accumulation of anthocyanin, glucosinolates, and phenolic compounds. For antioxidant activity, DPPH (2,2-diphenyl-1-picrylhydrazylradical) free radical scavenging, ABTS (2,2-azinobis (3-ethylbenzothiazoline)-6-sulfonic acid) radical scavenging, and reducing power assays were performed, and the antioxidant activity of red pakchoi baby leaves grown under red + blue LED light was found to be the best. The metabolic profiling of the identified metabolites revealed distinct separation based on the secondary metabolites. This research will be helpful for farmers to choose the best LED light combination to increase the secondary metabolic content in pakchoi plants.
... Total phenolic content was determined using Folin-Ciocalteu's reagent [28]. We weighed 0.5 g of alfalfa sprouts, grinded them with the assistance of liquid nitrogen, extracted it with 10 mL of finishing water in a centrifuge tube, centrifuged it at 4000 r/min for 20 min at 4 • C, and filtered it with a 0.22 µm filter head. ...
... DPPH is commonly used in chemical reactions involving free radicals to reflect the total antioxidant level of a substance [28,44]. The higher the DPPH free radical-scavenging rate, the higher the total antioxidant capacity of the substance. ...
Alfalfa sprouts are popular as a gourmet vegetable that contains a variety of antioxidants with anti-cancer and anti-coronary heart disease properties. In this study, under a photosynthetic photon flux density (PPFD) of 30 mol·L⁻¹ photoperiod of 12 h for 3 days, and a temperature of 25 ± 2 °C, we investigated the effects of different light qualities on the growth, nutritional quality and antioxidant activity of alfalfa sprouts by modulating LEDs with different red and blue ratios, and searched for suitable light-quality conditions for alfalfa sprout growth. The experimental results showed that the dark treatment favored the growth of alfalfa sprout hypocotyls and the increase of soluble sugar content; alfalfa fresh weight was the largest under the white and red light treatments; nitrate content was the lowest in the treatment with a red-to-blue ratio of 2:2 (2R2B); soluble proteins and total phenolic content were the highest in the treatment with red-to-blue ratio of 1:3 (1R3B); and the total antioxidant activity of sprouts was the highest in the blue light treatment.
... Several studies showed that the growth of hypocotyls, the phytochemical compound content, and the antioxidant capacity of sprouts are generally affected by environmental and genetic factors, among which light can play a crucial role [2]. Although sprouting usually occurs in the darkness, an increasing number of studies have revealed that artificial light sources could enhance the nutritional value of these foodstuffs [3][4][5][6][7]. ...
... Establishing whether light intensity may have a more relevant role than light quality on plant growth and development, and how these effects may vary among species and even cultivars, is still challenging. Moreover, few studies so far have investigated the effect of light quantity and quality on biochemical composition and antioxidant activities [3,23,24]. Based on the above information, the aim of this study was to explore the effect of pure blue and red light at different intensities on the growth, the content of some bioactive compounds, and the antioxidant capacities of lentil seedlings. ...
Simple Summary
Light-emitting diodes (LEDs) offer several advantages compared to conventional light sources. These systems are considered environmentally friendly tools to improve plant product quality. Controlling the light environment using this technology has shown positive effects, such as the potential to enhance plant photosynthesis and productivity, modulate the synthesis of bioactive compounds, extend the shelf life of fruits and vegetables, and increase resistance to biotic and abiotic stress. Among others, the possibility of using a narrow-band spectrum allows us to investigate the effects of single monochromatic light. In this study, we evaluated changes in some of the biometrical and biochemical parameters in lentil seedlings (Lens culinaris Medik.) grown under two wavelengths and three light intensities provided by LED lamps. Red light proved to have a strong effect on seedling elongation. In contrast, blue light affected the content of some bioactive compounds and enzymes. Research in plant–LED light interaction can provide insights for applications in agricultural conditions or indoor cultivations and contribute to understanding how light regulates plant growth and development.
Abstract
Light-emitting diodes are an attractive tool for improving the yield and quality of plant products. This study investigated the effect of different light intensity and spectral composition on the growth, bioactive compound content, and antioxidant metabolism of lentil (Lens culinaris Medik.) seedlings after 3 and 5 days of LED treatment. Two monochromatic light quality × three light intensity treatments were tested: red light (RL) and blue light (BL) at photosynthetic photon flux density (PPFD) of 100, 300, and 500 μmol m⁻² s⁻¹. Both light quality and intensity did not affect germination. At both harvest times, the length of seedling growth under BL appeared to decrease, while RL stimulated the growth with an average increase of 26.7% and 62% compared to BL and seedlings grown in the darkness (D). A significant blue light effect was detected on ascorbate reduced form, with an average increase of 35% and 50% compared to RL-grown plantlets in the two days of harvesting, respectively. The content of chlorophyll and carotenoids largely varied according to the wavelength and intensity applied and the age of the seedlings. Lipid peroxidation increased with increasing light intensity in both treatments, and a strong H2O2 formation occurred in BL. These results suggest that red light can promote the elongation of lentil seedlings, while blue light enhances the bioactive compounds and the antioxidant responses.
... Being an essential environmental factor, light is indispensable to the pho-to-morphogenesis and photosynthesis of plants in both natural and artificial conditions [4][5][6][7][8]. More than providing the energy for photosynthesis, light also dictates specific signals which regulate plant development, shaping, and metabolism, driven by light colors [6,9,10]. However, adverse weather like overcast, snow, rain, and fog in winter and spring always leads to inadequate light exposure, resulting in declined productivity of economic plants. ...
... These results agree with previous study [14]. There are some studies 9 recommend a mixed ratio of 1:1:1 among red, blue and white color supplemental lights to reduce the hardness of strawberries, but their quantitative chromatic parameters are not provided [24]. ...
Supplemental light is widely applied in greenhouses for promotions of the product and flavors of strawberries in global markets. Present selections of colored lights are, however, quite empirical or qualitative, from the aspect of photometry or colorimetry. The accurate control of chromatic parameters of supplemental light and their chromatic influences on fruit quality has been under-studied. In this study, color parameters including correlated color temperatures (CCTs) and illuminance of supplement lights are precisely controlled using a digitally color-coding method. We systematically investigate the chromatic effect of supplemental light on five parameters of strawberries: plant height, single weight, fruit hardness, soluble solids, and titratable acids. Results show that the supplement light generally lowers down the single weight and the fruit hardness, increases the plant height, the contents of soluble solids and titratable acids. The chromatic dependences for the five parameters are different and might be strengthened, weakened, or shifted by light illuminance. We demonstrate the beneficial roles of supplemental light in accelerating the maturation and enhancing the flavor of strawberries in greenhouses cultivation. The results pro-vide valuable guidance for the effective cultivation of strawberries. Moreover, the controlling method for accurate colors is ready for the implementation of supplemental lights in other fruits or plants.
... Te highest concentrations of carotenoids in the most shaded environments (lower RFA) are in line with the results verifed for mustard and Mizuna microgreens [44], however, they difer from the results verifed for baby leaf lettuce [45] and Brassica microgreens [46]. Te lowest levels of RFA provided higher levels of chlorophyll in kale microgreens as seen in arugula, kale, and mustard microgreens [47]. ...
Microgreens and baby leaves are increasingly appreciated and consumed due to the increased concentrations of antioxidant compounds, vitamins, nutrients, and minerals than adult plants. The objective was to evaluate the effect of different substrates and protected environments on the growth of microgreen and baby leaf kale (Brassica oleracea var. sabellica L.) and their contents of carotenoids and chlorophylls. The experiments were carried out in a completely randomized design in a factorial arrangement of 4 × 2 (four environments × two substrates) for the microgreens and 4 × 5 (four environments × five substrates) for the baby leaf, both with six replications. For microgreens, the Carolina Soil® commercial substrate promoted greater height, fresh matter, dry matter, productivity, chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids in all evaluated environments. In the greenhouse with a screen of 35% shading under the film, greater height, fresh matter, dry matter, and productivity were obtained, and in the greenhouse with a screen of 42/50% shading under the film, higher contents of microgreen chlorophylls and carotenoids were obtained. For baby leaves, the greenhouse with 42/50% shading screen under the film promoted plants with greater height, fresh matter, dry matter, and productivity in all substrates. The baby leaf grown in the greenhouse with a screen of 35% shading under the film showed higher chlorophyll and carotenoid contents in the pure Carolina Soil® substrate. For greater productivity, with higher contents of pigments, greenhouses with screens under the film and the use of organomineral commercial substrate are the most suitable for microgreen and baby leaf kale.
... Low solar radiation is harmful to the photosynthesis of rice, which hinders the accumulation and distribution of dry matter, resulting in a lower yield and poor quality of rice [11]. Artificial regulation and optimization of light conditions can improve the photosynthetic characteristics [12], promote crop growth [13], increase the yield [14], enhance the quality, and effectively delay the organ senescence of plants [15]. Some researchers have verified that light supplementation by LED can enhance the photosynthetic capacity of cucumber [16], and at bloom time, supplementary illumination can markedly promote the growth of cucumber fruits [17]. ...
To achieve higher economic returns, we employ inexpensive valley electricity for night-time supplementary lighting (NSL) of tomato plants, investigating the effects of various durations of NSL on the growth, yield, and quality of tomato. Tomato plants were treated with supplementary light for a period of 0 h, 3 h, 4 h, and 5 h during the autumn–winter season. The findings revealed superior growth and yield of tomato plants exposed to 3 h, 4 h, and 5 h of NSL compared to their untreated counterparts. Notably, providing lighting for 3 h demonstrated greater yields per plant and per trough than 5 h exposure. To investigate if a reduced duration of NSL would display similar effects on the growth and yield of tomato plants, tomato plants received supplementary light for 0 h, 1 h, 2 h, and 3 h at night during the early spring season. Compared to the control group, the stem diameter, chlorophyll content, photosynthesis rate, and yield of tomatoes significantly increased upon supplementation with lighting. Furthermore, the input–output ratios of 1 h, 2 h, and 3 h NSL were calculated as 1:10.11, 1:4.38, and 1:3.92, respectively. Nonetheless, there was no detectable difference in yield between the 1 h, 2 h, and 3 h NSL groups. These findings imply that supplemental LED lighting at night affects tomato growth in the form of light signals. Night-time supplemental lighting duration of 1 h is beneficial to plant growth and yield, and its input–output ratio is the lowest, which is an appropriate NSL mode for tomato cultivation.
... Other than yield, nutritional compound concentrations also change in response to different light conditions. For example, high B exposure can increase anthocyanin concentration in some plants (Samuolienėet al., 2012;. Anthocyanins are red-or purple-colored pigments with antioxidant activity (Khoo et al., 2017). ...
In controlled environment agriculture, customized light treatments using light-emitting diodes are crucial to improving crop yield and quality. Red (R; 600-700 nm) and blue light (B; 400-500 nm) are two major parts of photosynthetically active radiation (PAR), often preferred in crop production. Far-red radiation (FR; 700-800 nm), although not part of PAR, can also affect photosynthesis and can have profound effects on a range of morphological and physiological processes. However, interactions between different red and blue light ratios (R:B) and FR on promoting yield and nutritionally relevant compounds in crops remain unknown. Here, lettuce was grown at 200 µmol m⁻² s⁻¹ PAR under three different R:B ratios: R:B87.5:12.5 (12.5% blue), R:B75:25 (25% blue), and R:B60:40 (40% blue) without FR. Each treatment was also performed with supplementary FR (50 µmol m⁻² s⁻¹; R:B87.5:12.5+FR, R:B75:25+FR, and R:B60:40+FR). White light with and without FR (W and W+FR) were used as control treatments comprising of 72.5% red, 19% green, and 8.5% blue light. Decreasing the R:B ratio from R:B87.5:12.5 to R:B60:40, there was a decrease in fresh weight (20%) and carbohydrate concentration (48% reduction in both sugars and starch), whereas pigment concentrations (anthocyanins, chlorophyll, and carotenoids), phenolic compounds, and various minerals all increased. These results contrasted the effects of FR supplementation in the growth spectra; when supplementing FR to different R:B backgrounds, we found a significant increase in plant fresh weight, dry weight, total soluble sugars, and starch. Additionally, FR decreased concentrations of anthocyanins, phenolic compounds, and various minerals. Although blue light and FR effects appear to directly contrast, blue and FR light did not have interactive effects together when considering plant growth, morphology, and nutritional content. Therefore, the individual benefits of increased blue light fraction and supplementary FR radiation can be combined and used cooperatively to produce crops of desired quality: adding FR increases growth and carbohydrate concentration while increasing the blue fraction increases nutritional value.
... Flavonoids are important plant compounds that are produced as a result of stress to prevent DNA damage [41]. Light quality triggers different transcriptional genes that are used for the biosynthesis of flavonoids and could cause differences in the levels of flavonoid accumulation in plants [42]. ...
Microgreens are innovative vegetable products whose production and consumption are gaining popularity globally thanks to their recognized nutraceutical properties. To date, the effects of lighting conditions and growing substrate on the performances of Brassica carinata microgreens (indigenous to Africa) remain underexplored. The present study aimed at providing insights into the influence of different lighting treatments provided by LEDs, namely monochromatic blue (B), red (R), cool white (W) and a combination of three color diodes (B + R + W), and substrates (cocopeat, sand and cocopeat–sand mix (v/v) (1:1)) on the growth, yield and bioactive compounds of B. carinata microgreens. Seeds were germinated in dark chambers and cultivated in growth chambers equipped with LED lighting systems for 14 days under a fixed light intensity of 160 ± 2.5 µmol m⁻² s⁻¹ and photoperiod of 12 h d⁻¹. The best performances were associated with the spectrum that combined B + R + W LEDs and with substrate resulting from the cocopeat–sand mix, including the highest yield (19.19 g plant⁻¹), plant height (9.94 cm), leaf area (68.11 mm²) and canopy cover (55.9%). Enhanced carotenoid and flavonoid contents were obtained with B + R + W LEDs, while the B LED increased the total amount of chlorophyll (11,880 mg kg⁻¹). For plants grown under B + R + W LEDs in cocopeat, high nitrate levels were observed. Our results demonstrate that substrate and light environment interact to influence the growth, yield and concentration of bioactive compounds of B. carinata microgreens.
... RB light increased the flavonoid content in A. roxburghii by enhancing the expression of several related genes [32]. Illumination with blue light-emitting diodes (LEDs) induced anthocyanin accumulation in red lettuce [33]. Zhang et al. (2018a) showed that blue and red light increased the contents of total anthocyanins, pelargonidin 3-glucoside, and pelargonidin 3-malonyl glucoside in strawberry fruits [34]. ...
The spectral composition of light influences the biosynthesis of flavonoids in many plants. However, the detailed composition of flavonoids and anthocyanins and the molecular basis for their biosynthesis in strawberry fruits under two light-quality treatments, red light supplemented with blue light (RB) and ultraviolet B (UVB) irradiation, remain unclear. In this study, the content of flavonoids and anthocyanins was significantly increased in strawberry fruits under RB light and UVB, respectively. The content of flavonoids and anthocyanins in strawberry fruits under UVB light was dramatically higher than that in strawberry fruits irradiated with RB light, and a total of 518 metabolites were detected by means of LC-MS/MS analysis. Among them, 18 phenolic acids, 23 flavonoids, and 8 anthocyanins were differentially accumulated in the strawberry fruits irradiated with red/blue (RB) light compared to 30 phenolic acids, 46 flavonoids, and 9 anthocyanins in fruits irradiated with UVB. The major genes associated with the biosynthesis of flavonoids and anthocyanins, including structural genes and transcription factors (TFs), were differentially expressed in the strawberry fruits under RB and UVB irradiation, as determined through RNA-seq data analysis. A correlation test of transcriptome and metabolite profiling showed that the expression patterns of most genes in the biosynthesis pathway of flavonoids and anthocyanins were closely correlated with the differential accumulation of flavonoids and anthocyanins. Two TFs, bZIP (FvH4_2g36400) and AP2 (FvH4_1g21210), induced by RB and UVB irradiation, respectively, exhibited similar expression patterns to most structural genes, which were closely correlated with six and eight flavonoids, respectively. These results indicated that these two TFs regulated the biosynthesis of flavonoids and anthocyanins in strawberry fruit under RB light and UVB, respectively. These results provide a systematic and comprehensive understanding of the accumulation of flavonoids and anthocyanins and the molecular basis for their biosynthesis in strawberry fruits under RB light and UVB.
... However, when comparing photoperiod duration, it was found that a higher photoperiod duration had a negative effect on TAC, vitamin C and carotenoid content, suggesting that the 21 h duration might be the threshold. Thus, further studies need to be completed for these observations to be considered, as the levels are also dependent on a wide range of multicomponent factors and growing conditions [30]. ...
The effect of artificial lighting with different light spectra and photoperiods/daily light integrals (DLIs) on the yield, bioactive compounds and antioxidant capacity of the common ice plant (Mesembryanthemum crystallinum) was studied. Four-week-old seedlings were selected and subjected to four different light spectra made up of different combinations of blue (400–500 nm), green (500–600 nm) and red light (600–700 nm), with a total photosynthetic photon flux density (PPFD) of 180 µmol.m⁻².s⁻¹. Concurrently, the effect of the daily light integral (DLI) was also studied, with the light treatment photoperiod set at 18 h and 21 h. Biometric parameters such as fresh mass weight, leaf area, leaf width, and dry mass, together with plant metabolite contents such as total antioxidant capacity (TAC), vitamin C, chlorophyll a and b content, and total carotenoids and nitrates, were investigated. It was found that the plants grew better when exposed to light with a higher proportion of the red and blue spectrum, with the highest fresh mass of 68 g observed at a photoperiod of 18 h. On the other hand, green spectrum light was not found to yield any significant improvement in shoot weight, leaf area, or leaf size. It was also found that dry mass, chlorophyll b and nitrates were not influenced by the light spectrum but were influenced by the photoperiod duration. While both the dry mass and nitrate content increase as the photoperiod increases, a longer photoperiod had a negative effect on chlorophyll a, chlorophyll b and total carotenoids, with their content decreasing by as much 29% for chlorophyll a, 59% for chlorophyll b and 29% for total carotenoids. TAC content was seen to increase by more than 24% under the influence of 66% more green light, and 38% more under the 21 h photoperiod.
... Studies have shown that different light intensities, light qualities and photoperiods can indirectly regulate the expression of flavonoid-regulated genes and thus control the accumulation of flavonoids through the modulation of photosensitive pigments and cryptochromes (Jaakola, 2013). Benjamıń Battistoni et al. demonstrated that different ratios of light quality composition favored the synthesis of spinach flavonoids (Samuolienėet al., 2012). The changes in flavonoid content in kale leaves revealed that the accumulation of quercetin glucoside analog synthesis was promoted under strong light conditions, whereas the accumulation of kaempferol glucoside analog synthesis was inhibited, but the total flavonoid content was consistently higher in strong light than in weak light (Neugart et al., 2016). ...
Light is one of the important environmental factors affecting the growth and development of facility vegetables. In this experiment, we investigated the effects of different light intensities on the growth, nutritional quality and flavonoid accumulation of celery under hydroponic and full LED light conditions. Four light intensities of 40, 100, 200, or 300 µmol·m⁻²·s⁻¹ were set up in the experiment, and three harvest periods were set up on the basis of different light intensities, which were 15, 30, and 45 d after treatment (labeled as S1, S2, and S3, respectively). The results showed that the plant height and aboveground biomass of celery increased with the increase of light intensity, and the light intensity of 200 μmol·m⁻²·s⁻¹ was beneficial to increase the contents of chlorophyll, carotenoids, total phenols, vitamin C, cellulose, total flavones and apigenin in celery. During the S1-S3 period, the activities of PAL, CHS, CHI and ANS increased gradually under 200 and 300 μmol·m⁻²·s⁻¹ light intensity treatments, and the activities of FNS and CHS enzymes were the highest under 200 μmol·m⁻²·s⁻¹ light intensity treatment. The expression and ANS activity of Ag3GT, a key gene for anthocyanin synthesis, reached the maximum value at 300 μmol·m⁻²·s⁻¹, and the expression level and FNS activity of AgFNS, a key gene for apigenin synthesis, reached a maximum value at 200 μmol·m⁻²·s⁻¹. In general, the anthocyanin content was the highest at 300 μmol·m⁻²·s⁻¹, and the apigenin content was the highest at 200 μmol·m⁻²·s⁻¹. In conclusion, light intensity of 200 µmol·m⁻²·s⁻¹ treatment was more favorable for celery growth and nutrient synthesis.
... As an essential environmental factor, light is indispensable for the photomorphogenesis and photosynthesis of plants under both natural and artificial conditions [5][6][7][8][9]. In addition to providing the energy for photosynthesis, light also dictates specific signals which regulate plant development, shaping, and metabolism, driven by light colors [7,10,11]. However, adverse weather conditions, like overcast, snow, rain, and fog in winter and spring, always lead to inadequate light exposure, resulting in a decline in the productivity of economic plants. ...
Supplemental light is widely applied in greenhouses to promote the production and flavor of strawberries in global markets. The present selections of colored lights are, however, quite empirical or qualitative, from the perspective of photometry or colorimetry, which lacks precision. The accurate control of chromatic parameters of supplemental light and their chromatic influences on fruit quality have been under-studied. In this study, color parameters including ten groups of correlated color temperatures (CCTs-2250 K, 2400 K, 2600 K, 2800 K, 3000 K, 3500 K, 4000 K, 4500 K, 5000 K, and 6000 K) and two groups of illuminances (600 lx and 1000 lx) of supplemental lights were precisely controlled using a digital color-coding method applied to LED supplemental lights, and the strawberry was irradiated with the LED supplemental light from December 2021 to March 2022 in facilities cultivation (greenhouse). Moreover, the irradiation time was 6 h per day (4:00 a.m.–7:00 a.m., 5:00 p.m.–8:00 p.m.). We systematically investigated the chromatic effects of supplemental light on five parameters of strawberries: plant height, single weight, fruit hardness, soluble solids, and titratable acids. The results showed that the supplemental light generally lowered the single weight by 14% and fruit hardness by 6%, and increased plant height by 21%, the contents of soluble solids by 7.4%, and titratable acids by 27%. The chromatic dependences of the five parameters were different and might be strengthened, weakened, or shifted by light illuminance. Our results demonstrated the beneficial roles of supplemental light in accelerating maturation and enhancing the flavor of strawberries in greenhouse cultivation. These results provided valuable guidance for the effective cultivation of strawberries. Moreover, the controlling method for accurate colors was ready for the implementation of supplemental lights in other fruits or plants.
... Very importantly, both our study and the literature note that regardless of the type of antioxidant activity assay performed, it is statistically significantly reduced when treated with white light from fluorescent lamps (Fl) compared to LED light [60]. LED light increases the content of biomolecules which leads to a significant improvement in antioxidant properties [61] and free radical scavenging potential [62]. ...
Plants, whilst also having an ornamental role, are also a source of beneficial, bioactive compounds, and in vitro cultures are helpful in finding and obtaining them. Streptocarpus ×hybridus can be a source of antioxidants. The effect of different LED light qualities on the growth, development and metabolite composition of Streptocarpus multiplied in vitro on Murashige and Skoog medium was investigated. The used spectra were: 100% blue (B), 100% red (R), red and blue in 7:3 proportion (RB), 50% RB + 50% ultra violet (RBUV), 50% RB + 50% green (RBG), 50% RB + 50% yellow (RBY), 50% RB + 50% far red (RBfR), and white (WLed). A fluorescent lamp served as the control (Fl). For the best morphological quality of multiplied plants, the use of RBY light is recommended. Fl light reduced the antioxidant properties of extracts compared to LEDs. The most recommended spectrum in this aspect is RBfR, WLed, RBG and R light. These lights (except for R) stimulated the polyphenol content. RBY and R light influenced the highest content of free amino acids and reducing sugars. Studies showed that a selected LED light spectrum can influence the production of plant biomolecules with antioxidant properties and, compared to Fl light, improves the growth and development of multiplied plants.
... Exposure to different parts of the light spectrum plays a key role not only in the plants' growth and development, but also regarding the accumulation of secondary metabolites [20] and postharvest behavior and physiology [21]. According to the maturity stage, responses to various light spectra may vary amongst plant species or cultivars [22]. White and red LEDs have been shown to increase tomato yield [23], while blue LED light has been shown to improve tomato growth and development [24]. ...
The current study was carried out to monitor the dynamics of phenolic compounds and vitamin C variations in Hippophae rhamnoides L. (sea buckthorn) under the influence of different color filters, as follows: yellow (590 nm), blue (450 nm), and violet (400 nm). The fruits were harvested at maturity from different parts of the canopy (i.e., base, middle, and top), immediately stored at −18 °C, and afterward lyophilized to reduce the loss of compounds for preparing the chemical assays that were carried out. HPLC-DAD-ESI⁺ was used to determine the phenolic compounds and vitamin C content of the fruits. EPR (electron paramagnetic resonance) measurements were also carried out to confirm the antioxidant character of the berries. This is the first study to examine the effect of different color filters on the accumulation of phenolic compounds and vitamin C content in the fruits of sea buckthorn. Among the three color filters used, the violet filter proved to be the most beneficial for the accumulation of total phenolic compounds (3.326 mg/g) and vitamin C (1.550 mg/g) in the berries. To reach high contents of phenolic compounds and vitamin C, the best setup included using very-high-energy emission LEDs as close as possible to blue and violet (400–450 nm). Therefore, the different light color intensities and temperatures on each level of a canopy play key roles in enhancing the phenolic compound content, antioxidant activity, and vitamin C content of sea buckthorn fruits. This knowledge will help provide insights into the accumulation of secondary metabolites and improve future production strategies in sea buckthorn.
... Active phytochrome signaling, triggered by red light, enhances the sensitivity of cryptochromes to blue light, amplifying their regulatory effects on anthocyanin-related genes [105,106]. This interplay between cryptochromes and phytochromes ensures a coordinated response to different light qualities and intensities, ultimately influencing the biosynthesis of anthocyanins in plants [107,108]. ...
Light is a crucial environmental factor that profoundly influences the growth and development of plants. However, the precise mechanisms by which light affects biochemical processes and growth and development factors in Thymus vulgaris remain unknown, necessitating further investigation. Hence, this study aimed to investigate the impact of different light spectra, including red, blue, red-blue, and white lights, on the morphological characteristics, primary, and specialized metabolites of T. vulgaris. Compared to white light, red light significantly increased leaf area (by 64 %), the number of branches (by 132 %), and dry weight (by 6.2 %), although a 40 % reduction in fresh weight was observed under red light conditions. Red-blue light notably enhanced canopy width, fresh weight, and dry weight. Gas chromatography/mass spectrometry (GC/MS) analysis of the plant's essential oil (EO) revealed that p-Cymene and γ-Terpinene were present at the highest levels. Notably, p-Cymene exhibited the highest concentrations under white light and blue light treatments, reaching 60.92 % and 59.53 %, respectively. Moreover, under the same light conditions, phenol and antioxidant levels were significantly elevated. Overall, these findings indicate that red and red-blue light spectra are the most favorable for thyme production.
... The orange Chinese cabbage with high lycopene content serves as an excellent research material for studying the carotenoid metabolism pathway of vegetable crops (Zhang et al., 2013). The phenomena of color change regulated by light have been reported in cauliflower (Kopsell & Sams, 2013), citrus (Zhang et al., 2012), poplar (Ren et al., 2020), pea seedling (Wu et al., 2007) and green leaf lettuce (Samuolienė, Sirtautas, Brazaitytė, & Duchovskis, 2012). To date, little is known about the effects of various monochromatic light qualities on carotenoid accumulation in the inner leaves of orange Chinese cabbage. ...
... In addition to physiological and morphological changes, light spectra can also affect the synthesis of metabolites in herbs, thus modifying their biological activities. Blue LED irradiation increased the DPPH scavenging capacity of baby leaf lettuce and improved its antioxidant properties [51], and callus cultures of Rhodiola imbricata grown under blue light also displayed the highest antioxidant activity compared to other light conditions [52]. Consistently, in this study, antioxidant capacities-especially DPPH and ABTS scavenging activities-were significantly promoted by blue light and inhibited by red light. ...
Basil (Ocimum basilicum Linn. var. pilosum (Willd.) Benth.) is an aromatic plant with high nutritional and economic value, and the synthesis and regulation of its active ingredients have been studied in prior research. However, the mechanisms by which red and blue light—the most effective absorption spectra for photosynthesis—regulate the growth and metabolism of basil remain elusive. This study investigated the changes in phenotype, transcriptome, and metabolome in basil under red and blue light. The photosynthetic efficiency and biomass of basil under blue light (B) treatment were higher than those under white light (W), while red light (R) decreased photosynthesis and biomass. Metabolomic analysis showed that 491 significantly differentially accumulated metabolites were identified between the W and B groups, while 630 differentially accumulated metabolites were identified between the W and R groups. The DAMs were mainly enriched in pathways such as biosynthesis of secondary metabolites, monoterpenoid biosynthesis, limonene and pinene degradation, etc. In addition, transcriptomic analysis revealed that 34,760 and 29,802 differentially expressed genes were detected in the W vs. B pair and the W vs. R pair, respectively, while differentially expressed genes were divided into different unique subclasses, suggesting that they respond to light quality in specific ways. Overall, this work will not only enrich knowledge of the molecular mechanisms of light spectra’s regulation of plant metabolism, but also provide a theoretical basis and guidance for the molecular improvement and quality cultivation of basil.
... Additionally, growing plants under different wavelengths of light exposure results in physiological changes [56]. For example, it has been reported that the type and intensity of the wavelength can affect the enhancement of carotenoid pigment and glucosinolate concentrations [57,58]. ...
Policosanols (PCs) are long-chain linear aliphatic alcohols that are present in the primary leaves of cereal crops, such as barley and wheat, sugar cane wax, and beeswax. PCs have been used as a nutraceutical for improving hyperlipidemia and hypercholesterolemia. However, the PC content in mutant wheat lines has not been investigated. To select highly functional wheat sprouts with a high content of PCs in wheat mutant lines developed via gamma-irradiated mutation breeding, we cultivated the sprouts of wheat mutant lines in a growth chamber with white LED light (6000 K) and analyzed the PC content in these samples using GC-MS. We studied the PC content in 91 wheat sprout samples: the original variety (Woori-mil × D-7; WS01), commercially available cv. Geumgang (WS87) and cv. Cheongwoo (WS91), and mutant lines (WS02–WS86 and WS88–WS90) developed from WS01 and WS87. Compared to WS01, 18 mutant lines exhibited a high total PC content (506.08–873.24 mg/100 g dry weight). Among them, the top 10 mutant lines were evaluated for their PC production after cultivating under blue (440 nm), green (520 nm), and red (660 nm) LED light irradiation; however, these colored LED lights reduced the total PC production by 35.8–49.7%, suggesting that the cultivation with white LED lights was more efficient in promoting PCs’ yield, compared to different LED lights. Therefore, our findings show the potential of radiation-bred wheat varieties as functional foods against hyperlipidemia and obesity and the optimal light conditions for high PC production.
... Light quality also affects fruit quality by influencing the accumulation of organic compounds (Samuolienė et al., 2012). ...
... Two crucial features of the greenhouse time series are seasonality and tendency, which can be found in the irregularities and noises in the data. The growing crops in the greenhouse exhibit a seasonal pattern, and the periodical cycle of greenhouse climate can be shorter than natural seasons [31][32][33]. Additionally, different growing periods of crops can create a short-term tendency in dynamic climate parameters [34,35]. ...
The greenhouse farming always uses sensors to monitor the dynamic climate parameters and generate time-related data. The prediction of these time series contributes a lot to greenhouse cultivation. Plenty of works concentrate on the chaotic characteristics of the time series and propose many machine learning-based models. However, the intrinsic features of them are ignored, i.e., seasonality and tendency. In this study, we propose a novel predicting model SDN that utilizes the Seasonal-trend Decomposition as preprocessing method and the Single Dendrite Neuron as nonlinear fitter to tackle greenhouse time series predictions. The decomposition gives SDN a flexibility that can process each component separately, while the well-designed neuron structure provides SDN with time efficiency. Accordingly, the experimental results show that the proposed SDN not only beats the widely used machine learning-based models, but also shows the robustness considering customized parameters and outliers in datasets, which enhance the possibility for SDN to be employed in the practical usage scenarios.
... In the last two decades, LEDs have been regarded as new light sources for plant production both in controlled environments and in plant physiological studies (Brown et al., 1995;Yanagi and Okamoto, 1997;Samuolienė et al., 2012;Bantis et al., 2016;Viršilė et al., 2017;Wu et al., 2020). The advantages of LED sources include high optical efficiency, considerable energy saving, low volume, long lifetime, low energy production, adjustable energy intensity and quality, followed by the absence of harmful UV rays. ...
Article type: Increasing day length during the short photoperiod in fall and winter is a beneficial method of increasing biomass production and altering plant morphology and phytochemistry. The objective of this study was to examine the effects of light quality at the end of the day (EoD) on the growth and phytochemical characteristics of lemon balm. During short-day photoperiods in autumn, lemon balm (Melissa officinalis L.) seedlings were exposed to red, blue, and combined red/blue light using light-emitting diodes for 2 hours at the EoD. The results showed that exposure to red light significantly increased biomass. Plants grown under blue light yielded the highest percentage of dry matter and their leaves had the highest chlorophyll content and flavonoids. The highest carotenoid content was found in plants irradiated with blue light and later with red+blue light. The highest levels of total phenols, anthocyanins, and antioxidant activity were found in plants grown under red light. In addition, light quality had a significant effect on essential oil content. The highest essential oil content was obtained in the red and red+blue light treatments. The light quality at the EoD significantly changed the essential oil composition. The blue light significantly increased the citronellal content but decreased the geranial and linalool content. This study provided insights into the effects of Eo D light quality on plant growth and metabolite accumulation in lemon balm with a short photoperiod. In conclusion, supplemental light at the EoD can effectively improve plant growth and secondary metabolite quality in medicinal plants.
... LED is considered as a tool to promote and develop efficient plants (Folta, & Carvalho, 2015). It is used as a light source or as supplement to natural lighting (Li, & Kubota, 2009;Johkan, Shoji, Goto, Hashida, Yoshihara, 2010;Samuolienė, Sirtautas, Brazaityte, & Duchovskis, 2012;Choi, Moon, & Kang, 2015) usually under controlled conditions (Folta, & Carvalho, 2015;Yoshida, Hikosaka, Goto, Takasuna, & Kudou, 2012;Lin et al, 2013;Piovene et al, 2015). This study determined the efficacy of LED supplementary lighting in improving growth and fruit yield and quality of watermelon grown in plastic houses. ...
Watermelon plants cultivar ‘Kinaree 457’ were grown in plastic house under natural daylight only (control) or with nightly LED supplementary lighting for 6 h (6:00 pm-12:00 pm) or 12 h (6:00 pm-6:00 am) starting from transplanting up to fruit harvest. Plant height, leaf chlorophyll content and fruit yield significantly increased in response to 6 h supplementary LED lighting. Fruit mass, size (length x width) and flesh thickness at 6 h LED treatment were about 2.3 kg, 19.3 ×15.7 cm, and 15.7 cm, respectively, while the fruit of control had 1.7 kg, 16.0 × 14.3 cm, and 13.8 cm, respectively. No significant treatment effect was obtained on peel thickness, flesh color L* and b* values, juice pH and total soluble solids. However, 6 h LED treatment resulted in lower reddening flesh (lower a* values), firmness and higher titratable acidity relative to the control, suggesting the need for improvement in cultural management. Furthermore, multivariate statistics of principal component analysis (PCA) performed on physico-chemical quality revealed the variations among watermelons from lighting and control treatments regardless of lighting hour.
... Metabolic profiling has proven to be a powerful tool for gaining insights into functional biology. For instance, blue light induced higher levels of anthocyanin accumulation in red lettuce, strawberry fruit and grape (Li et al. 2017;Samuoliene et al. 2012;Saure 1990); as well as increase the contents of chlorogenic acid, gallic acid, ferulic acid, and other phenolic substances in pea seedlings (Liu et al. 2016). Moreover, red light mainly promotes stem growth by regulating gibberellin biosynthesis in "Manicure Finger" (Vitis vinifera L.) grape plantlets (Li et al. 2017), and exposure to both red and blue light (RB) for three months stimulated carotenoid biosynthesis, which is a sign of a slower decay of product compounds after harvest in tomatoes (Appolloni et al. 2023). ...
Different light spectra from light-emitting diodes (LEDs) trigger species-specific adaptive responses in plants. We exposed Artemisia argyi (A. argyi) to four LED spectra: white (the control group), monochromatic red light (R), monochromatic blue light (B), or a mixture of R and B light of photon flux density ratio is 3 (RB), with equivalent photoperiod (14 h) and light intensity (160 μmol s⁻¹ m⁻²). R light accelerated photomorphogenesis but decreased biomass, while B light significantly increased leaf area and short-term exposure (7 days) to B light increased total phenols and flavonoids. HPLC identified chlorogenic acid, 3,5-dicaffeoylquinic acid, gallic acid, jaceosidin, eupatilin, and taxol compounds, with RB and R light significantly accumulating chlorogenic acid, 3,5-dicaffeoylquinic acid, and gallic acid, and B light promoting jaceosidin, eupatilin, and taxol. OJIP measurements showed that B light had the least effect on the effective quantum yield ΦPSII, with higher rETR(II), Fv/Fm, qL and PIabs, followed by RB light. R light led to faster photomorphology but lower biomass than RB and B lights and produced the most inadaptability, as shown by reduced ΦPSII and enlarged ΦNPQ and ΦNO. Overall, short-term B light promoted secondary metabolite production while maintaining effective quantum yield and less energy dissipation.
... Loose-leaf lettuce has the highest total phenolic compounds (338 mg 100 g −1 ) and is a moderate source of vitamin C and β-carotene. The accumulation of minerals and bioactive compounds in lettuce strongly depends on environmental factors, such as temperature [13] and the quality, intensity, and duration of light [14][15][16][17]. Previous studies have also indicated that nitrogen deficiency favorably affects the biosynthesis of phenolic acids, flavonols, anthocyanins, and ascorbic acid in lettuce [18,19]. ...
The integration of indoor vertical cultivation with a recirculating aquaculture system into an aquaponic system has the potential to become one of the most effective sustainable production systems for fish and leafy vegetables. In this study, lettuce was produced on rafts in a coupled recirculation aquaponic system in the plant factory under controlled environmental conditions. The aims of this study were to evaluate the yield, mineral status, and health-promoting bioactive compounds of leaf and romaine lettuce cultivars grown in a recirculating aquaponic system. The yield and biometric parameters and quality parameters of lettuce leaves (nitrate, mineral, L-ascorbic acid, carotenoid, phenolic compound, and total polyphenolic contents) were examined. Monitoring of the water in the aquaponic system showed a low concentration of nitrates, phosphorus (P), potassium (K), and magnesium (Mg), but the proportion of mineral nutrients as well as pH were stable throughout the lettuce cultivation period. The heads of romaine lettuce ‘Yakina’, ‘Pivotal’, and ‘Waygo’ reached a fresh weight of 86 g, on average, 23% higher than the leaf lettuce ‘Nordice’ over a three-week cultivation period. Despite the low nutrient concentration in the aquaponic solution, the nutrient status of the romaine lettuces ‘Yakina’ and ‘Pivotal’ was within the optimal range. The concentrations of chlorophyll a and carotenoids in ‘Yakina’ and ‘Pivotal’ were higher than those in ‘Nordice’ and ‘Waygo’. The nitrate, phosphorus, and potassium contents in the leaves of ‘Nordice’ and ‘Waygo’ were below the optimal range; however, their polyphenol concentrations were the highest. Our results indicate that the effectiveness of aquaponic cultivation of lettuce in terms of biomass production and the nutritional and health-promoting value of lettuce depends on the plant genotype.
... White light, however, had a positive impact on the vitamin C content of both green and red lettuce. This finding agrees with other reports that suggest that achieving a positive impact on the content of vitamin C is complex, because metabolism of antioxidant properties in lettuce depends on multicomponent exposure of variety, light quality and several other factors related to the growing conditions [41]. Light spectra also impacted the total phenol content in both lettuce varieties, and focusing the lights in the red/blue region significantly increased the accumulation of phenols. ...
Controlled Environment Agriculture (CEA) is a method of increasing crop productivity per unit area of cultivated land by extending crop production into the vertical dimension and enabling year-round production. Light emitting diodes (LED) are frequently used as the source of light energy in CEA systems and light is commonly the limiting factor for production under CEA conditions. In the current study, the impact of different spectra was compared with the use of white LED light. The various spectra were white; white supplemented with ultraviolet b for a week before harvest; three combinations of red/blue lights (red 660 nm with blue 450 nm at 1:1 ratio; red 660 nm with blue 435 nm 1:1 ratio; red 660 nm with blue at mix of 450 nm and 435 nm 1:1 ratio); and red/blue supplemented with green and far red (B/R/G/FR, ratio: 1:1:0.07:0.64). The growth, yield, physiological and chemical profiles of two varieties of lettuce, Carmoli (red) and Locarno (green), responded differently to the various light treatments. However, white (control) appeared to perform the best overall. The B/R/G/FR promoted the growth and yield parameters in both varieties of lettuce but also increased the level of stem elongation (bolting), which impacted the quality of grown plants. There was no clear relationship between the various physiological parameters measured and final marketable yield in either variety. Various chemical traits, including vitamin C content, total phenol content, soluble sugar and total soluble solid contents responded differently to the light treatments, where each targeted chemical was promoted by a specific light spectrum. This highlights the importance of designing the light spectra in accordance with the intended outcomes. The current study has value in the field of commercial vertical farming of lettuce under CEA conditions.
... According to the previous reports, red and blue light displayed signi cant effects on phenolics accumulation. (Samuolienė et al. 2012) demonstrated that when red LED light was applied for 16 h before harvest, the phenolic content in red and light-green leaf lettuce was increased by 52.7 and 14.5%. ...
Lonicera macranthoides , a medicinal herb mainly distributed in South China, is widely utilized in Chinese traditional medicines for its high yield and strong pharmacological properties rich in phenolic acids and flavonoids. However, the factors regulating plant growth and secondary metabolism in L. macranthoides are still largely unknown. In this study, the effects of different light qualities and hormone combinations on seedlings growth performance and metabolites production were investigated. The results showed that plants under red light produced greatest biomass of the shoots and roots, and also promoted plant photosynthesis as indicated by significantly greater values for Pn, Gs, Ci, and Tr, followed by white and blue LED. The tissue culture seedlings exhibited maximum plant height and stem diameter on the medium with 1.0mg/L 6-benzyladenine (BA) + 1.0mg/L Indole 3-butyric acid (IBA), while produced the highest amounts of phenolic acids and flavonoids in medium containing 2.0mg/L BA + 0.2mg/L IBA. Red light dramatically enhanced the accumulation of chlorogenic acid (CGA), ferulic acid, luteoloside, and rutin than those under other light spectra conditions on the medium with low level of auxin. However, higher levels of auxin dramatically inhibited the CGA production under red light. Moreover, blue light can promote the accumulation of chlorogenic acid and luteoloside on these two media. The results indicate that the plant growth and secondary metabolism were dramatically influenced by light quality and auxin/cytokinin combinations. Light and auxin signaling crosstalk programmed secondary metabolites accumulation. Our findings provide effective strategies aiming to enhance biomass yield and bioactive compounds production in L. macranthoides .
... The antioxidant activity of F. saxatilis was estimated using DPPH and ABTS radical scavenging assays. The DPPH radical scavenging activity of F. saxatilis was consistent with that of the total phenol and flavonoid compounds and with previous studies, in which an increase in phytochemicals led to a significant improvement in radical scavenging activity when various combinations of LEDs were used (Samuolienė et al. 2012;Zhao et al. 2020;Manivannan et al. 2015;Oh et al. 2021). Therefore, it was concluded that the combination of R and B light at a ratio of 7:3 (R7B3) enhanced the antioxidant activity of F. saxatilis by increasing the content of functional substances, such as phenols and flavonoids. ...
Forsythia saxatilis is an endangered species endemic to Korea. Here, we determined the effects of light quality on the growth and antioxidant activity of F. saxatilis. Six different light conditions were used: white (W10, control); combined light-emitting diodes (LED) of white (W) and far-red (Fr) at 10:1 (W10Fr1); combined LED of red (R) and blue (B) at 5:5 (R5B5); combined LED of R and B at 7:3 (R7B3); combined LED of R, green (G), and B at 7:1:2 (R7G1B2); and a combined LED of R, G, B, and Fr at 7:1:2:1 (R7G1B2Fr1). Forsythia saxatilis shoot formation was the highest with R7G1B2 at 89%, whereas the greatest growth-promoting effects—that is, increase in plant height, leaf length and width, and fresh and dry weights of shoots and roots—were achieved with W10Fr1. The total phenol and flavonoid contents were the highest with R7B3. The activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) were the highest with R7B3 treatment. In summary, W10Fr1 treatment was found to be the most effective for the growth of F. saxatilis, whereas R7B3 was confirmed to be the most effective for maximizing antioxidant activity.
... A similar pattern was also recorded in LED + HA treatments, with 100B + HA and 25R:75B + HA showing the maximum vitamin C content. In a similar experiment, the vitamin C content increased in baby leaf lettuce (Samuolienė et al., 2012) and parsley microgreens (Carillo et al. (2022) under 100B LED light. Other authors concluded that a high proportion of blue light might induce the formation of ascorbic acid (Tan et al., 2020). ...
Belonging to the Brassicaceae family, rocket (Eruca sativa (Mill.) Thell.), is considered to be a nitrate-accumulating leafy vegetable. Many studies show that light-emitting diode (LED) lights can be a suitable tool to decrease anti-nutritional compounds (e.g., nitrate (and enhance antioxidant and nutritional quality for phytochemical-rich vegetable production. The positive influence of humic acid on health-promoting compounds in different crops is also well documented. This study aimed to investigate the effects of supplemental LED lights of various spectral compositions, namely 25–100% red, 25–100% blue, and 100% white, as well as their combination with humic acid on the physiological and biochemical responses of rocket plants. ANOVA results showed that almost all the measured traits were significantly affected by LED and humic acid treatments. Generally, LED combined with humic acid improved the accumulation of nutritional compounds (e.g., polyphenols, flavonoid, ascorbic acid, carbohydrate, tannin), increased the activity of key enzymes involved in nitrogen metabolism (e.g., nitrate reductase, nitrite reductase, and glutamine synthetase), and lowered nitrate and ammonium concentrations. The results of principal component analysis indicated that the combination of LED lights, regardless of the spectra, with humic acid was the most effective treatment to enhance the nutritional value and activity of enzymes involved in nitrate assimilation. In sum, these findings may be used as a reference in rocket production for supplemental LED light optimization and its combination with humic acid.
Light is essential for vegetable growth, with varying combinations of light quality affect differently on plant growth and development. In order to clarify the optimal light quality combination of celery LEDs, under hydroponic and full LED light conditions, this study investigated distinct combinations of light quality have various impacts on the growth and quality of celery using “Hongcheng Red Celery” as test material. Red-blue (R:B = 3:1, control), red-blue-purple (R:B:P = 3:1:1, purple (P)), red-blue-green (R:B:G = 3:1:1, green (G)), red-blue-yellow (R:B:Y = 3:1:1, yellow (Y)), and red-blue-far-red (R:B:FR = 3:1:1, far-red (FR)) light conditions were set up in the experiment, and plants were treated for 45 days. The findings indicated that the best growth in celery was achieved under the RBP, while RBG inhibited the growth of celery. The chlorophyll a and total chlorophyll contents of celery leaves were increased significantly by the RBP treatments compared to RB. In addition, net photosynthetic rate, stomatal conductance, and transpiration rate were highest in RBP. In RBP treatment, soluble protein, vitamin C, total phenols, total flavonoids, Ca, Fe, Zn in leaves and petioles of celery were higher than in other treatments. And the anthocyanins content in celery petioles was higher than other treatments. The RBP and RBG treatments reduced nitrate content. The RBP treatment increased the activities of apigenin synthesis-related enzymes CHS, FNS, ANS, and up-regulated expression of related genes CHS, FNS, and ANS, and increased apigenin content. In summary, the RBP is more favorable for celery growth and nutrient synthesis.
Aquaponics is a sustainable food production system that combines aquaculture and hydroponics. However, limited studies focused on the nutritional and functional properties of aquaponic produce. Thus, this study aimed to explore the nutritional and functional components of four leaf lettuce lines with different colors cultivated in a commercial aquaponic farm in four seasons from summer 2022 to spring 2023. The leaf lettuce lines grown in aquaponics had high levels of micronutrients such as vitamin C, vitamin K, and folic acid, with the levels of vitamin K and folic acid meeting Japan's health claim criteria. The lettuce lines, especially red leaf lettuce, were also rich in bioactive compounds such as nitrate ions, which are linked to blood pressure regulation, and antioxidants such as anthocyanins and chlorogenic acid. These findings suggest that leaf lettuce grown in aquaponics has potential use as a high-value functional food.
The postharvest lighting environment is a main factor that influences quality preservation for harvested biomass. The objective of this study was to evaluate postharvest changes in bioactive compounds of lettuce with different storage light spectra. The effects of green LEDs with peaks at 500 nm and 530 nm, white LEDs (400–700 nm), and dark storage were evaluated, where light intensity (10 μmol m⁻² s⁻¹) and photoperiod (12 h per day) were constant with air temperature at 5°C over the 14 d treatment period. Lettuce stored with 500 nm and 530 nm green LEDs exhibited 1474.5% and 1451.8% (approximately 15.7 and 15.5 times) higher antioxidant activity, respectively, compared to dark storage. Significant improvements in total phenolic content, and 67.5% and 64.8% increases in total soluble solids with 530 nm and 500 nm green LEDs over dark storage were discerned. Exposure to 530 nm green LEDs led to 128.2% (approximately 2.28 times) higher anthocyanin content, a 26.2% increase in carotenoids, and a 95% rise in flavonoid content compared to dark storage. Increases of 26.4% and 16.0% in chlorophyll a content in lettuce stored under 500 nm and 530 nm green LEDs, respectively, and 65.6% and 46.6% rises in the Chlorophyll a/b ratio were observed. Compared to dark storage, green LEDs (500 nm) resulted in a 13.5% higher total chlorophyll content. Findings underscore the positive impact of green LEDs on the nutritional quality of lettuce, providing insight for postharvest practices.
This review paper of literature highlights role of Light Emitting Diode (LED) on the growth of plants under controlled conditions of greenhouse farming particularly hydroponics. "Internet of Things (IOT)" is a system of interconnected computing devices, sensors, objects, microcontrollers, and cloud servers that can transmit data across a network and control other devices remotely without human intervention. Light Emitting Diode (LED) is a more efficient, versatile, lasts longer, highly energy-efficient, directional, narrow light spectrum, low power consumption, and little heat production. Common LED colors include amber, red, green, and blue. Hydroponic grow lights are designed to mimic the natural light that plants need for photosynthesis. Plants can only use the spectrum of visible light to produce photosynthesis, and this narrow spectrum (400 to 700 nanometer) is recognized as the Photosynthetically Active Radiation (PAR). The development and growth of diverse plant species can be influenced differently by a variety of colored LED lights. LED illumination provides an efficient way to improve yield and modify plant properties. Therefore, LED systems plays an important role in controlling morphological, genetic, physiological, chemical properties, increasing the synthesis of a variety of beneficial secondary metabolites, and optobiological interactions of plants in greenhouse farming. In general, red and blue light is essential for maximizing the photosynthesis process due to their strong absorption by the plant chlorophyll molecules. LED illumination sources are increasingly being utilized to enhance the growth rate of vegetables and herbs cultivated in greenhouses worldwide. LED illumination spectrum manipulation could enable significant morphological adaptations, and identification of the wavelength ranges is required to increase the plant photosynthesis process.
Bacterial volatile organic compounds (BVOCs) are biological volatiles that can have a positive effect on the postharvest preservation of fruits and vegetables. In the present study, fumigation of broccoli with BVOCs released by Lysinibacillus fusiformis supplemented with light‐emitting diode (LED) white light irradiation reduced the accumulation of reactive oxygen species in broccoli during senescence, enhanced the synthesis and accumulation of antioxidant substances, and increased antioxidant enzyme activity in stored broccoli. Compared to the control group (CK), transcriptomic and metabolic analyses of the composite treatment group (LED‐BVOCs) on the 4 days of storage identified 3/1, 7/0, 1/1, 20/6, and 6/1 differentially expressed genes (DEGs)/differentially abundant metabolites in metabolic pathways related to ascorbic acid, glutathione, glucosinolate, polyphenols, and methionine, respectively, and there were 4 DEGs involved in the regulation of senescence during ethylene signal transduction. It is evident that LED‐BVOCs treatment can effectively regulate the metabolic processes of antioxidants in broccoli during storage. Overall, the LED‐BVOCs treatment improved the antioxidant capacity and reduced ethylene production in stored broccoli, thus delaying senescence. Our study provides new insights on the ability of using BVOCs as biopreservatives to improve the antioxidant capacity and delay senescence of broccoli during storage.
The controlled environment ecosystem is a meticulously designed plant growing chamber utilized for cultivating biofortified crops and microgreens, addressing hidden hunger and malnutrition prevalent in the growing population. The integration of speed breeding within such controlled environments effectively eradicates morphological disruptions encountered in traditional breeding methods such as inbreeding depression, male sterility, self-incompatibility, embryo abortion, and other unsuccessful attempts. In contrast to the unpredictable climate conditions that often prolong breeding cycles to 10–15 years in traditional breeding and 4–5 years in transgenic breeding within open ecosystems, speed breeding techniques expedite the achievement of breeding objectives and F1–F6 generations within 2–3 years under controlled growing conditions. In comparison, traditional breeding may take 5–10 years for plant population line creation, 3–5 years for field trials, and 1–2 years for variety release. The effectiveness of speed breeding in trait improvement and population line development varies across different crops, requiring approximately 4 generations in rice and groundnut, 5 generations in soybean, pea, and oat, 6 generations in sorghum, Amaranthus sp., and subterranean clover, 6–7 generations in bread wheat, durum wheat, and chickpea, 7 generations in broad bean, 8 generations in lentil, and 10 generations in Arabidopsis thaliana annually within controlled environment ecosystems. Artificial intelligence leverages neural networks and algorithm models to screen phenotypic traits and assess their role in diverse crop species. Moreover, in controlled environment systems, mechanistic models combined with machine learning effectively regulate stable nutrient use efficiency, water use efficiency, photosynthetic assimilation product, metabolic use efficiency, climatic factors, greenhouse gas emissions, carbon sequestration, and carbon footprints. However, any negligence, even minor, in maintaining optimal photoperiodism, temperature, humidity, and controlling pests or diseases can lead to the deterioration of crop trials and speed breeding techniques within the controlled environment system. Further comparative studies are imperative to comprehend and justify the efficacy of climate management techniques in controlled environment ecosystems compared to natural environments, with or without soil.
Strawberries are a widely consumed fruit that are increasingly popular due to the perceived health benefits associated with their consumption. Fruit quality is highly dependent on the growing environment where light is one of the most significant environmental factors influencing plant physiology and metabolism. In the present work we sought to test the hypothesis that manipulation of the light environment in a commercial growing environment would influence fruit yield and quality. Fruit were grown with supplemental light-emitting diodes in the red (623 nm), far-red (727 nm) and blue (470 nm) regions of the spectrum at three different densities. The majority of light treatments resulted in increased fruit yield. All treatments also significantly enhanced contents of anthocyanins and polyphenols. Furthermore fruit exhibited enhanced antioxidant activity. Individual strawberry sugars showed differences depending on sampling date whereas Brix, acidity and ascorbic acid was not affected by the LED lights. Strawberry fruit extracts from all treatments exhibited the capacity to inhibit the digestive enzymes pancreatic lipase and α-amylase activity in vitro, extract from fruit grown under supplemental lighting had a greater inhibitory capacity. These data suggest that strawberry fruit grown in the presence of supplemental light may impart health benefits via enhanced functional compounds and by limiting calorific assimilation. The findings of this study provide the first evidence that the use of light-emitting diodes increase the inhibitory effects of polyphenols on digestive enzymes in strawberry.
Günümüzde dünya nüfusu hızlı bir artış trendi içerisinde yer almakta olup, nüfus artışı barınma ihtiyacını artırmakta ve bununla birlikte sanayii üretim alanlarına olan talebin artması beraberinde tarım alanları üzerindeki baskının her geçen gün giderek artmasına neden olmaktadır. Tarım alanları azalırken, nüfus artışına bağlı olarak insanların gıdaya olan talebi de her geçen gün artış göstermektedir. Özellikle köylerin sahip olduğu zayıf sosyal hayat koşulları tarımdaki iş gücünün şehirlere kaymasına neden olmakta, kentleşme oranını artırmakta ve bunların neticesinde tarımsal üretim sınırlamaktadır. Mevcut koşullar yeni üretim tekniklerinin uygulanarak üretim artışının teşvik edilmesi gerekliliğini ortaya çıkarmıştır. Son yıllarda ortaya çıkan kent çiftçiliği uğraşı oluşan sorunların çözümüne ve gıda arzına katkıda bulunmayı hedeflemektedir. Bitkilerin çimlenmeden sonraki süreçte büyüme ve gelişmelerinde en önemli çevresel faktörlerden birisi ışıktır. Bitkisel üretimde yapay ışık kaynaklarının kullanımı güneş ışığını desteklemek amacıyla kullanılabildiği gibi, güneş ışığı olmayan yetiştirme kabinleri veya dolaplarında da yapay ışık kaynakları kullanılabilmektedir. LED aydınlatmalar günümüzde ışık ve enerji verimliliğinin yüksek olması, kullanım ömrünün uzun olması, ısı oluşumunun düşük olması gibi özellikleri ile ek aydınlatmada bitkiler için önemli bir rol oynamaktadır. Bu çalışmada gelecekte kullanmak zorunda olacağımızı düşündüğümüz ve günümüz sebze tarımında kullanımı dikkat çekici etkiye sahip yapay ışık kaynakları ve bu alanda yapılan çalışmaların sonuçları derlenmiştir.
Lonicera macranthoides, a medicinal herb mainly distributed in southern China, is widely utilized in traditional Chinese medicine for its high yield and strong pharmacological properties rich in phenolic acids and flavonoids. However, the factors regulating plant growth and secondary metabolism in L. macranthoides remain largely unknown. In this study, the effects of seven light qualities and plant growth regulators combinations on seedlings growth and metabolite accumulation were investigated. Plants under red light produced the greatest shoot and root biomass, and promoted plant photosynthesis, as indicated by significantly greater values of net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), and transpiration rate (Tr), followed by white and blue light. The plant height and stem diameter of the tissue-cultured seedlings on the medium with 1.0 mg/L 6-benzyladenine (BA) + 1.0 mg/L indole 3-butyric acid (IBA) were the highest, while the seedlings on the medium containing 2.0 mg/L BA + 0.2 mg/L IBA produced the highest amounts of phenolic acids and flavonoids. Red light dramatically enhanced the accumulation of chlorogenic acid (CGA), ferulic acid, luteoloside, and rutin compared to those under other light spectrum conditions on media with low levels of auxin (0.2 mg/L IBA). However, higher auxin levels (1.0 mg/L IBA) dramatically inhibited CGA production under red light. Moreover, blue light promoted the accumulation of chlorogenic acid and luteoloside. The results indicate that the plant growth and secondary metabolism were dramatically influenced by light quality and auxin/cytokinin combinations. Our findings provide effective strategies aiming to enhance biomass yield and bioactive compound production in L. macranthoides.
تهدف دراسة تأثير بعض العوامل الفيزيائية والكيميائية في تحفيز وإنتاج المركبات الفعالة طبيا من نبات .Tanacetum parthenium L المزروع خارج وداخل الجسم الحي
Artificial light application is an effective method for promoting potato production in indoor facilities. In this study, we assessed the effects of different combinations of red (R) and blue (B) light application on potato leaf and tuber growth. Potato plantlets were transplanted under W (white light, control), RB5–5 (50% R + 50% B), RB3–7 (30% R + 70% B to 70% R + 30% B) and RB1–9 (10% R + 90% B to 90% R + 10% B), and ascorbic acid (AsA) metabolism in leaves and cytokinin (CTK), auxin (indole-3-acetic acid, IAA), abscisic acid (ABA), and gibberellin (GA) levels in tubers were measured. At 50 days of treatment, potato leaves had significantly higher L-galactono-1,4-lactone dehydrogenase (GalLDH) activity and utilized AsA faster under RB1–9 treatment than under RB3–7 treatment. CTK/IAA and ABA/GA ratios in large tubers under W treatment did not differ significantly from those under RB1–9 treatment, which had higher levels than those under RB5–5 and RB3–7 treatment at 50 days. However, under RB1–9 treatment, total leaf area decreased rapidly from 60 to 75 days compared with plants under RB3–7 treatment. Tuber dry weight per plant under W and RB5–5 treatment approached a plateau at 75 days. At 80 days, RB3–7 treatment significantly improved ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase activity compared with RB1–9 treatment. RB1–9 treatment with a high ratio of blue light increased CTK/IAA and ABA/GA to improve tuber bulking at 50 days, while RB3–7 treatment with a high ratio of red light stimulated AsA metabolic pathway to delay leaf oxidation and maintain tuber biomass accumulation at 80 days. For the indoor potato cultivation, RB3–7 treatment had a higher proportion of medium-sized tubers, thus being a suitable light treatment.
This study was carried out in the greenhouse of the Horticulture Department Nursery, College of Agriculture Engineering Sciences, Duhok University, Kurdistan region, Iraq, for the period from 1st Aug 2020 to 1st Mar 2021, to study the effect of five supplemental light (control, natural light, Incandescent 14, Incandescent 18, mixed 14, mixed 18) hours daily and three growing medium (river soil, river soil + 30% local compost, river soil + 60% local compost) on some vegetative growth and flowering of two cultivars of carnation plant. The best results (fewest days) for the number of days from planting to bud emergence, visible flower colour, and anthesis were obtained when the plants were exposed to mixed light colours or incandescent lamps for a 14-hour treatment, Also this treatments were significantly superior in the other characteristics like plant height, flower length and flower diameter compared to the control. Medium with 60% local compost significantly increased all the studied characteristics compared with other mediums. The Ormea (Red) cultivar was significantly superior to the Moonlight cultivar in all studies of characteristics and was early in day numbers for bud emergence, visible flower colour, and anthesis. All second interactions between the investigated factors had a significant influence in all studied characteristics. In addition, the triple interaction between the three factors had a significant impact on all characteristics, including the least days or fewest days to flower anthesis of the Ormea cultivar when planted on medium containing 60% local compost under incandescent 14h, which took 101.80 days compared 176.27 days, with an early reach of 74.47 days for the control. The Moonlight (white) cultivar required the fewest days, 128.93 days, for a medium containing 60% compost under mixed 14h, which needed 123.93 days, compared to the control, which required 195.87 days with an early flowering rate of 71.94 days.
Pinus pseudostrobus Lindl. is a species endemic to Mexico and is widely used in reforestation programmes, as it is highly adapted to poor, shallow, limestone soils and has high commercial importance. However, it is necessary to preserve this genetic material since it is in trouble due to high rates of deforestation, land use change, and forest fires, so it is necessary to have effective strategies to obtain good quality seedlings. Due to the properties of LED (light emitting diode) lamps used for illumination in the production of in vitro plants, the effects of two different lighting systems (LED and fluorescent) on an in vitro culture were analysed for the morphological characteristics of the growth and photosynthetic pigment content in P. pseudostrobus seedlings. The length and root size of the seedlings were affected by the type of illumination, where a red LED light was the most effective at 30 days of evaluation. However, a blue LED light was equally effective as a red LED light at 60 days of seedling development. On the other hand, the fluorescent light was better in terms of the number of needles in the first stage, but we found the blue LED light to be better in the second stage. For the photosynthetic pigment content, the highest values were found with the blue LED light. The results showed that the LED lighting system favours the growth, development, and photosynthetic pigment content of the species under study.
The aims of this study consist on anthocyans isolation from black grapes skin by different extraction methods in order to select the best choice, as well as the spectrophotometric characterization of anthocyans extracts (quantitative analysis, indices for pigment degradation, color density, polymeric color and stability study during time at ambient temperature). The study is justified by two major reasons: first the proved antioxidant effect of anthocyans and their importance for health and the second the worldwide trend for replacing synthetic foods colorants with natural pigments among them anthocyans being situated in first place because of their intense and diverse colors as well as for their protective effect.
The results show that black grapes skin has rich anthocyans content (325.216- 323.456 mg/100g fresh products), the index for pigment degradation are between 40.4% - 41.77% in fresh products, the color density values are from 1.59 to 2.68 and the anthocyans extracts have a good stability during time (289.335 – 316.962 mg/100g fresh products).
Keywords: anthocyans, index for pigment degradation, color density, polymeric color, black grapes
Five cultivars of leaf lettuce (Lactuca sativa L. var. crispa) - Bergamo, Dubáček, Frisby, Lollo Rossa and Redin - were evaluated in two-year experiments carried out at the Faculty of Horticulture in Lednice (Mendel University of Agriculture and Forestry in Brno). Experiments were conducted in two trial years, 1998 and 1999; the lettuce was cultivated in three seasons: spring, summer and autumn. After the harvest, contents of following nutrients were evaluated: vitamin C, minerals (K, Na, Ca, Mg), fibre, dry matter and nitrates. The weight of leaf rosette was also recorded. The contents of selected substances and weights of leaf rosette were ranged as follows: vitamin C (65 to 302 mg/kg), potassium (2,394 to 6,477 mg/kg), sodium (39 to 223 mg/kg), calcium (200 to 755 mg/kg), magnesium (110 to 413 mg/kg), fibre (4.98 to 12.22 g/kg), dry matter (59 to 140 g/kg), nitrates (293 to 3,817 mg/kg) and the weight of leaf rosette (164 to 502 g). A significant influence of cultivar was found in the case of K, Na, and Ca content, as well as in dry matter and weight of leaf rosette. The growing season affected significantly all the evaluated substances, except for fibre. The year of cultivation affected all the evaluated parameters but Ca. It appears from the results that the contents of monitored substances were significantly influenced by cultivar as well as by growing season and year.
In precise field trials in the Czech Republic from 2004-2008 the impact of location conditions, varieties with yellow, purple and red flesh and mineral fertilization on the content of total polyphenols (TP) and chlorogenic acid was investigated. The highest TP contents were reported at two locations with extreme climatic conditions; in those under stress due to low temperatures in the vegetation period at the mountainous area Stachy (5.89 mg TP/g DM) and those under drought stress in the warm lowland location Přerov nad Labem with light sandy soil (5.81 mg TP/g DM). The five-year experiment with the purple-fleshed Valfi variety (13.29 mg TP/g DM) reached 2.46 to 3.18 times higher content of TP in comparison with eight yellow-fleshed varieties. The yellow-fleshed Karin variety (5.39 mg TP/g DM) outperformed TP content of other yellow-fleshed varieties by 3.1 to 29.1%. In another experiment conclusive differences between the eight varieties with purple and red flesh were found; the highest TP content was detected in cv. Violette (25.9 mg TP/g DM) with the darkest purple flesh. As to the chlorogenic acid content similar relationships between varieties were found as in the case of TP. High linear correlation (r = 0.8536) was found between the content of chlorogenic acid and the content of TP. Among the treatments of mineral N, P, K and Mg fertilization, the content of TP was only affected by a treatment with a higher dose of K and Mg, causing a decrease in TP content.
Lactuca sativa cv. Outredgeous was grown under either fluorescent lamps or light-emitting diodes (LEDs) to test the hypothesis that antioxidant potential could be regulated by light quality. Red leaf lettuce was grown at 300 μmol·m-2·s-1 of photosynthetically active radiation, 1200 μmol·mol-1 CO2, 23°C, and an 18 h-light /6-h dark photoperiod in controlled-environment chambers. The LED treatments were selected to provide different amounts of red (640 nm), blue (440 nm), green (530 nm), and far-red (730 nm) light in the spectra. Total anthocyanin content and the oxygen radical absorbance capacity of the tissue were measured at harvest. The source of light had a dramatic effect on both plant growth and production of radioprotective compounds. LEDs resulted in 50% greater bioprotectant content per plant at the same light level over triphosphor fluorescent lamps. Blue LEDs (440 nm) appeared to regulate the metabolic pathways leading to increased concentration of bioprotective compounds in leaf tissue. LED lighting induced a number of effects on morphology that increased both accumulation of bioprotective compounds and total yield.
Tocopherols are lipophilic antioxidants that are synthesized exclusively in photosynthetic organisms. In most higher plants, alpha- and gamma-tocopherol are predominant with their ratio being under spatial and temporal control. While alpha-tocopherol accumulates predominantly in photosynthetic tissue, seeds are rich in gamma-tocopherol. To date, little is known about the specific roles of alpha- and gamma-tocopherol in different plant tissues. To study the impact of tocopherol composition and content on stress tolerance, transgenic tobacco (Nicotiana tabacum) plants constitutively silenced for homogentisate phytyltransferase (HPT) and gamma-tocopherol methyltransferase (gamma-TMT) activity were created. Silencing of HPT lead to an up to 98% reduction of total tocopherol accumulation compared to wild type. Knockdown of gamma-TMT resulted in an up to 95% reduction of alpha-tocopherol in leaves of the transgenics, which was almost quantitatively compensated for by an increase in gamma-tocopherol. The response of HPT and gamma-TMT transgenics to salt and sorbitol stress and methyl viologen treatments in comparison to wild type was studied. Each stress condition imposes oxidative stress along with additional challenges like perturbing ion homeostasis, desiccation, or disturbing photochemistry, respectively. Decreased total tocopherol content increased the sensitivity of HPT:RNAi transgenics toward all tested stress conditions, whereas gamma-TMT-silenced plants showed an improved performance when challenged with sorbitol or methyl viologen. However, salt tolerance of gamma-TMT transgenics was strongly decreased. Membrane damage in gamma-TMT transgenic plants was reduced after sorbitol and methyl viologen-mediated stress, as evident by less lipid peroxidation and/or electrolyte leakage. Therefore, our results suggest specific roles for alpha- and gamma-tocopherol in vivo.
The influence of variety and the level of maturity on the content and composition of carotenoids in toma-toes were monitored in a field experiment in the year 2007. A total of 11 varieties were submitted to this experiment – Albertovské žluté, Bejbino F1, Cristina F1, Bonset F1, Dominato F1, Monika F1, Orkado F1, Start S F1, Stupické polní rané, Tornádo F1 and Rougella F1. A significant difference in the ability of tomatoes to synthesise carotenoids in relation to variety was found. At the mature phase of fruits an average content of carotenoids was determined as 665 μg/g dry mass. The varieties with high content of carotenoids were Bonset F1, Start S F1 and Cristina F1. On the contrary, the varieties with low ability in carotenoids production are Albertovské žluté, Bejbino F1 and Tornádo F1. The main carotenoids determined at the red-fruit tomatoes were lycopene, β-carotene and lutein. In the yellow-fruited variety – Albertovské žluté, only β-carotene and lutein was found.
The blue part of the light spectrum has been associated with leaf characteristics which also develop under high irradiances.
In this study blue light dose–response curves were made for the photosynthetic properties and related developmental characteristics
of cucumber leaves that were grown at an equal irradiance under seven different combinations of red and blue light provided
by light-emitting diodes. Only the leaves developed under red light alone (0% blue) displayed dysfunctional photosynthetic
operation, characterized by a suboptimal and heterogeneously distributed dark-adapted Fv/Fm, a stomatal conductance unresponsive to irradiance, and a relatively low light-limited quantum yield for CO2 fixation. Only 7% blue light was sufficient to prevent any overt dysfunctional photosynthesis, which can be considered a
qualitatively blue light effect. The photosynthetic capacity (Amax) was twice as high for leaves grown at 7% blue compared with 0% blue, and continued to increase with increasing blue percentage
during growth measured up to 50% blue. At 100% blue, Amax was lower but photosynthetic functioning was normal. The increase in Amax with blue percentage (0–50%) was associated with an increase in leaf mass per unit leaf area (LMA), nitrogen (N) content
per area, chlorophyll (Chl) content per area, and stomatal conductance. Above 15% blue, the parameters Amax, LMA, Chl content, photosynthetic N use efficiency, and the Chl:N ratio had a comparable relationship as reported for leaf
responses to irradiance intensity. It is concluded that blue light during growth is qualitatively required for normal photosynthetic
functioning and quantitatively mediates leaf responses resembling those to irradiance intensity.
Maximal l4CO2-fixation in spinach occurs in the middle of the palisade mesophyll [Nishio et al. (1993) Plant Cell 5: 953], however, ninety percent of the blue and red light is attenuated in the upper twenty percent of a spinach leaf [Cui
et al. (1991) Plant Cell Environ. 14: 493]. In this report, we showed that green light drives 14CO2-fixation deep within spinach leaves compared to red and blue light. Blue light caused fixation mainly in the palisade mesophyll
of the leaf, whereas red light drove fixation slightly deeper into the leaf than did blue light. 14CO2-fixation measured under green light resulted in less fixation in the upper epidermal layer (guard cells) and upper most palisade
mesophyll compared to red and blue light, but led to more fixation deeper in the leaf than that caused by either red or blue
light. Saturating white, red, or green light resulted in similar maximal 14CO2-fixation rates, whereas under the highest irradiance of blue light given, carbon fixation was not saturated, but it asymptotically
approached the maximal 14CO2-fixation rates attained under the other types of light. The importance of green light in photosynthesis is discussed.
The plant blue light receptor, phot1, a member of the phototropin family, is a plasma membrane-associated flavoprotein that contains two ( approximately 110 amino acids) flavin-binding domains, LOV1 and LOV2, within its N terminus and a typical serine-threonine protein kinase domain at its C terminus. The LOV (light, oxygen, and voltage) domains belong to the PAS domain superfamily of sensor proteins. In response to blue light, phototropins undergo autophosphorylation. E. coli-expressed LOV domains bind riboflavin-5'-monophosphate, are photochemically active, and have major absorption peaks at 360 and 450 nm, with the 450 nm peak having vibronic structure at 425 and 475 nm. These spectral features correspond to the action spectrum for phototropism in higher plants. Blue light excitation of the LOV2 domain generates, in less than 30 ns, a transient approximately 660 nm-absorbing species that spectroscopically resembles a flavin triplet state. This putative triplet state subsequently decays with a 4-micros time constant into a 390 nm-absorbing metastable form. The LOV2 domain (450 nm) recovers spontaneously with half-times of approximately 50 s. It has been shown that the metastable species is likely a flavin-cysteine (Cys(39) thiol) adduct at the flavin C(4a) position. A LOV2C39A mutant generates the early photoproduct but not the adduct. Titrations of LOV2 using chromophore fluorescence as an indicator suggest that Cys(39) exists as a thiolate.
Absorption and reflectance spectra of maple (Acer platanoides), cotoneaster (Cotoneaster alaunica), dogwood (Cornus alba) and pelargonium (Pelargonium zonale) leaves with a wide range of pigment content and composition were studied in visible and near-infrared spectra in order to reveal specific anthocyanin (Anth) spectral features in leaves. Comparing absorption spectra of Anth-containing and Anth-free leaves with the same chlorophyll (Chl) content, absorption spectra of Anth in leaves were derived. The main spectral feature of Anth absorption in vivo was a peak around 550 nm; the peak magnitude was closely related to Anth content. A quantitative nondestructive technique was developed to subtract Chl contribution to reflectance in this spectral region and retrieve Anth content from reflectance over a wide range of pigment content and composition. Anth reflectance index in the form ARI = (R550)-1 - (R700)-1, where (R550)-1 and (R700)-1 are inverse reflectances at 550 and 700 nm, respectively, allowed an accurate estimation of Anth accumulation, even in minute amounts, in intact senescing and stressed leaves.
Light has a profound effect on plant growth and development. Red and blue light best drive photosynthetic metabolism, so it is no surprise that these light qualities are particularly efficient in advancing the developmental characteristics associated with autotrophic growth habits. Photosynthetically inefficient light qualities also impart important environmental information to a developing plant. For example, far-red light reverses the effect of phytochromes, leading to changes in gene expression, plant architecture, and reproductive responses. Recent evidence shows that green light also has discrete effects on plant biology, and the mechanisms that sense this light quality are now being elucidated. Green light has been shown to affect plant processes via cryptochrome-dependent and cryptochrome-independent means. Generally, the effects of green light oppose those directed by red and blue wavebands. This review examines the literature where green light has been implicated in physiological or developmental outcomes, many not easily attributable to known sensory systems. Here roles of green light in the regulation of vegetative development, photoperiodic flowering, stomatal opening, stem growth modulation, chloroplast gene expression and plant stature are discussed, drawing from data gathered over the last 50 years of plant photobiological research. Together these reports support a conclusion that green light sensory systems adjust development and growth in orchestration with red and blue sensors.
To determine the contribution of photosynthesis on stomatal conductance, we contrasted the stomatal red light response of wild-type tobacco (Nicotiana tabacum 'W38') with that of plants impaired in photosynthesis by antisense reductions in the content of either cytochrome b(6)f complex (anti-b/f plants) or Rubisco (anti-SSU plants). Both transgenic genotypes showed a lowered content of the antisense target proteins in guard cells as well as in the mesophyll. In the anti-b/f plants, CO(2) assimilation rates were proportional to leaf cytochrome b(6)f content, but there was little effect on stomatal conductance and the rate of stomatal opening. To compare the relationship between photosynthesis and stomatal conductance, wild-type plants and anti-SSU plants were grown at 30 and 300 micromol photon m(-2) s(-1) irradiance (low light and medium light [ML], respectively). Growth in ML increased CO(2) assimilation rates and stomatal conductance in both genotypes. Despite the significantly lower CO(2) assimilation rate in the anti-SSU plants, the differences in stomatal conductance between the genotypes were nonsignificant at either growth irradiance. Irrespective of plant genotype, stomatal density in the two leaf surfaces was 2-fold higher in ML-grown plants than in low-light-grown plants and conductance normalized to stomatal density was unaffected by growth irradiance. We conclude that the red light response of stomatal conductance is independent of the concurrent photosynthetic rate of the guard cells or of that of the underlying mesophyll. Furthermore, we suggest that the correlation of photosynthetic capacity and stomatal conductance observed under different light environments is caused by signals largely independent of photosynthesis.
Light-emitting diodes (LEDs) are semiconductor devices that produce noncoherent, narrow-spectrum light when forward voltage is applied. LEDs range in wavelength from the UVC band to infrared (IR) and are available in packages ranging from milliwatts to more than 10 W. The first LED was an IR-emitting device and was patented in 1961. In 1962, the first practical visible spectrum LED was developed. The first high-power (1-W) LEDs were developed in the late 1990s. LEDs create light through a semiconductor process rather than with a superheated element, ionized gas, or an arc discharge as in traditional light sources. The wavelength of the light emitted is determined by the materials used to form the semiconductor junction. LEDs produce more light per electrical watt than incandescent lamps with the latest devices rivaling fluorescent tubes in energy efficiency. They are solid-state devices, which are much more robust than any glass-envelope lamp and contain no hazardous materials like fluorescent lamps. LEDs also have a much longer lifetime than incandescent, fluorescent, and high-density discharge lamps (U.S. Dept. of Energy). Although LEDs possess many advantages over traditional light sources, a total system approach must be considered when designing an LED-based lighting system. LEDs do not radiate heat directly, but do produce heat that must be removed to ensure maximum performance and lifetime. LEDs require a constant-current DC power source rather than a standard AC line voltage. Finally, because LEDs are directional light sources, external optics may be necessary to produce the desired light distribution. A properly designed LED light system is capable of providing performance and a lifetime well beyond any traditional lighting source.
Solid-state lighting based on the use of light-emitting diodes (LEDs) is potentially one of the biggest advancements in horticultural lighting in decades. LEDs can play a variety of roles in horticultural lighting, including use in controlled environment research, lighting for tissue culture, and supplemental and photoperiod lighting for greenhouses. LED lighting systems have several unique advantages over existing horticultural lighting, including the ability to control spectral composition, the ability to produce very high light levels with low radiant heat output when cooled properly, and the ability to maintain useful light output for years without replacement. LEDs are the first light source to have the capability of true spectral composition control, allowing wavelengths to be matched to plant photoreceptors to provide more optimal production and to influence plant morphology and composition. Because they are solid-state devices, LEDs are easily integrated into digital control systems, facilitating special lighting programs such as "daily light integral" lighting and sunrise and sunset simulations. LEDs are safer to operate than current lamps because they do not have glass envelopes or high touch temperatures, and they do not contain mercury. The first sustained work with LEDs as a source of plant lighting occurred in the mid-1980s to support the development of new lighting systems to be used in plant growth systems designed for research on the space shuttle and space station. These systems progressed from simple red-only LED arrays using the limited components available at the time to high-density, multicolor LED chip-on-board devices. As light output increases while device costs decrease, LEDs continue to move toward becoming economically feasible for even large-scale horticultural lighting applications.
The effects of several wavelength selective light filters placed on developing mature green tomato fruits were studied to determine whether light environment during fruit ripening has an impact on fruit composition. Juice titratable acidity and fruit fresh and dry weight varied little with the different filters. Reducing the red/far-red light ratio with a green filter to simulate vegetation shade slightly delayed ripening. Reducing infrared light (700-1100 nm) reduced vitamin C and soluble sugars content. A drastic reduction in photosynthetic light (97%) reduced both β-carotene (-23%) and lycopene (-29%) contents and red coloration (-21%). Significant correlations were found among the content of soluble sugars, vitamin C and lycopene, but these components increased differently according to the spectral composition of the light transmitted to the fruit. The content of lycopene and β-carotene increased with exposure to photosynthetic radiation and more precisely with exposure to blue light. In contrast, the content of vitamin C and sugar increased with infrared light exposure.
The effects of light quality on biomass and internal quality of leaf lettuce, spinach and komatsuna were examined. The plants were grown hydroponically in an environmentally controlled room with a 12-h light period and under a light/dark temperature of 20 ± 1°C/18 ± 1°C and a photosynthetic photon flux density (PPFD) of 300 μmol m-2 s-1 under four light quality treatments, i.e., red light from red fluorescent lamps (R) or blue light from blue fluorescent lamps (B) or a mixture of R and B (RB) or white light from white fluorescent lamps (W). The irradiation of R compared with W increased shoot dry weight in komatsuna and decreased the nitrate content in spinach. Irradiation of B or RB compared with W increased the L-ascorbic acid content in leaf lettuce and komatsuna and decreased the nitrate content in leaf lettuce. Irradiation of B was not suitable for the spinach cultivation due to an extremely decreased shoot dry weight although the carotenoid content was slightly increased. Our data show that controlling light quality is useful to achieve higher productivity or higher nutritional quality of the commercial crops even under limited light intensity in controlled-environment agricultural facilities although the effective light quality treatment differs depending on the plant species.
Antioxidant activity of extracts of barley leaves cultivated by light emitting diode (LED) radiation such as red, far-red, blue, blue-red, green, yellow, and white light was investigated. After measuring length and weight of the leaves cultivated, barley leaves were extracted using 70% ethanol. The Hunter color value, total phenolic compounds, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salts (ABTS) radical-scavenging activities of extracts were determined. Lengths of samples cultivated by red and green light radiation were 13.7 and 13.6 cm, respectively. Hunter L* values of samples cultivated by red, far-red, and UVA radiation were 65.29, 67.55, and 67.57, respectively. The content of total phenolic compounds of samples cultivated by blue light radiation was 1.62 mg/L of sample. The DPPH radical-scavenging activities of samples cultivated by blue, green, UVA, and white light radiation were 64.28, 48.92, 55.95, and 48.72%, respectively. The ABTS radical-scavenging activity of samples cultivated by blue light radiation scored higher compared with those of samples cultivated with other LED lights. Antioxidant activities of barley leaves showed different results depending on harvest time. Application of LED radiation during re-cultivation after the first harvest showed increasing tendency on antioxidant activity of barley leaves.
Major antioxidants and antioxidant activity in eight varieties of tomatoes were determined. Hydrophilic and lipophilic antioxidant activity (HAA and LAA) was determined by the ABTS assay and ascorbic acid and carotenoid contents were determined by HPLC-DAD. The HAA has far more significant impact on total antioxidant activity (83%) as compared with LAA. HAA was increasing during all ripening stages and was strongly correlated with ascorbic acid content (r = 0.83). During the ripening the LAA was increasing till the III. stage of maturity and then decreased. The main carotenoids determined in the red-fruit tomatoes were lycopene, β-carotene and lutein. The content of lycopene has been increasing equally during the ripening. β-Carotene and lutein were intensively synthesized between the I. and II. stage of maturity. Among ascorbic acid, α-tocopherol, lycopene, β-carotene and lutein standards ascorbic acid was determined as the most efficient antioxidant followed by α-tocopherol and β-carotene. Antioxidant activity of ascorbic acid, α-tocopherol, β-carotene and lutein grew equally with increasing concentration, however lycopene was the most effective in its lowest concentration. The analysis of two-component mixtures showed significant synergism between lycopene-lutein, lycopene-β-carotene and α-tocopherol-β-carotene.
Effects of light and nutritional conditions on the ascorbic acid content in hydroponically grown lettuce of butterhead type (Luctuca sativa L. cv. Edogawa or Okayama) were investigated. With increasing levels of shading, the fresh weight and number of leaves decreased, the shape of leaves became narrower and ascorbic acid and sugars content decreased markedly, while nitrate nitrogen content inclined to increase. Plants grown in 1/4 strength standard nutrient solution were inferior in fresh weight and number of leaves to those grown in 1/2 strength solution. Though ascorbic acid and sugars content was higher for plants grown in 1/4 strength solution at higher light intensities, the effect of nutrient concentration gradually disappeared with increasing shading level.Diurnal changes in leaf constituents were studies on sunny and cloudy days. The contents of ascorbic acid, sugars and chlorophyll were higher in the daytime and lower during the night, while nitrate nitrogen content increased in the night time. These tendencies were more clear on the sunny day than on the cloudy day.The relations between the contents of ascorbic acid, sugars, nitrate nitrrogen etc. were discussed and possible techniques of practical use for improving the quality of hydroponically grown leaf vegetables were also discussed.
Using UV-A, blue (B), green (G), red (R), and far-red (FR) light-emitting diodes (LEDs), we investigated the effects of different supplemental light qualities on phytochemicals and growth of ‘Red Cross’ baby leaf lettuce (Lactuca sativa L.) grown at a high planting density under white fluorescent lamps as the main light source inside a growth chamber. Photon flux added by supplemental LEDs for UV-A, B, G, R and FR were 18, 130, 130, 130 and 160μmolm−2s−1, respectively. Photosynthetic photon flux (PPF, 400–700nm), photoperiod, and air temperature (day/night) was 300μmolm−2s−1, 16h, and 25°C/20°C in all treatments including white light control. After 12 days of light quality treatment (22 days after germination), phytochemical concentration and growth of lettuce plants were significant affected by light treatments. Anthocyanins concentration increased by 11% and 31% with supplemental UV-A and B, respectively, carotenoids concentration increased by 12% with supplemental B, phenolics concentration increased by 6% with supplemental R while supplemental FR decreased anthocyanins, carotenoids and chlorophyll concentration by 40%, 11% and 14%, respectively, compared to those in the white light control. The fresh weight, dry weight, stem length, leaf length and leaf width significantly increased by 28%, 15%, 14%, 44% and 15%, respectively, with supplemental FR light compare to white light, presumably due to enhanced light interception by enlarged leaf area under supplemental FR light. Although the mechanisms of changes in phytochemicals under different supplemental light quality are not well known, the results demonstrated that supplemental light quality could be strategically used to enhance nutritional value and growth of baby leaf lettuce grown under white light.
The aim of this work was to test 13 edible seeds for the levels of phenolic compounds and the antioxidant activity (TAC) at different germination states (dormant, imbibed and 7d sprouts). Selected seeds included mungbean, alfalfa, fava, fenugreek, mustard, wheat, broccoli, sunflower, soybean, radish, kale, lentil and onion. Accumulated phenolics (mg chlorogenic acid equivalent, CAE) and TAC (μg Trolox equivalent) on dry basis (DB) showed the general trend distribution of 7d sprouts>dormant seeds>imbibed seeds. In addition, the specific TAC (μg Trolox mg−1 CAE) increased only for imbibed seeds indicating a possible protection effect of the phenolic antioxidants to the emerging sprouts. Phenolic contents of 7d sprouts (DB) ranged from 490 (lentil) to 5676 (mustard)mg CAE 100g−1. Seven day sunflower sprouts had higher TAC on a DB (40202μgTroloxg−1) compared to other seeds (1456–25991) and a blueberry reference (35232). Increases in phenolics (DB) from dormant seed to 7d sprout differ among seeds, ranging from 2010% (mungbean) to −11% (kale), while increases in TAC (DB) ranged from 1928% (mungbean) to 0% (lentil). This study shows that germinated edible seeds are an excellent source of dietary phenolic antioxidants.
Blue light has been suggested to participate in the acclimation of photosynthesis to growth irradiance. We analyzed the effects of blue light intensity on the photosynthetic properties of leaves with regard to acclimation to irradiance. Spinach (Spinacia oleracea L.) plants were grown under mixtures of blue and red light with blue-light photon flux densities (PFDs) of 0, 30, 100 and 150 µmol m−2 s−1 at a total photosynthetic PFD of 300 µmol m−2 s−1. The light-saturated rate of photosynthesis under white light, leaf N content per unit leaf area, leaf dry weight per unit leaf area and the ratio of cytochrome (Cyt) f content to light-harvesting chlorophyll-binding protein of photosystem II (LHCII) content were evaluated. The photosynthetic rate tended to increase with increasing blue-light PFD up to 100 µmol m−2 s−1, and this was associated with an increase in leaf N content per unit leaf area. However, the increase in leaf N content per unit leaf area did not necessarily result from an increase in leaf dry weight per unit leaf area. The Cyt f to LHCII content ratio increased linearly with increasing blue-light PFD up to 100 µmol m−2 s−1, indicating that plants grown under higher blue-light PFD up to this value resembled plants grown under higher irradiance in terms of N partitioning between electron-transport components and light-harvesting components. This result suggests that the level of blue light is involved only in the acclimation to relatively low growth irradiances at the chloroplast level.
Lettuce is a popular leafy vegetable and plays an important role in American diet and nutrition. Crisphead lettuce has much lower nutrient content than leaf and romaine types. As the synthesis or absorption of many nutrients is light dependent, the lower nutritional value of crisphead lettuce is due to the enclosure of its leaves in a head structure. In addition to varietal differences, nutritional quality of lettuce may be influenced by environmental factors such as light, temperature, growing season, cultural practices, fertilizer application, and storage conditions. The moisture content of the plant also affects nutrient concentration. Enhancing the nutritional levels of vegetables would improve the nutrient intake without requiring an increase in consumption. Genotypic variation in germplasm suggests that genetic improvement of nutritional value is feasible in lettuce. However, breeding efforts for nutrition are often hampered by the lack of analytical capabilities in most crop improvement programs. Biotechnology has the potential to markedly increase the nutritional value of lettuce. The commercialization of transgenic lettuce may largely depend on progress in transgene expression, public acceptance, economic and marketing challenges, intellectual property issues, and risk assessment.
Influence of light-emitting diode (LED) light on antioxidant activity of radiated pea seedlings was first studied using red (625–630 nm) and blue (465–470 nm) LED lights as light sources in an attempt to determine and compare the changes in chlorophyll and β-carotene contents, and Trolox equivalent antioxidant capacity (TEAC, μM). After radiation for 96 h, comparing to white light group, red light radiated seedlings displayed significant (p < 0.05) increases in stem length and leaf area, while blue light radiation significantly (p < 0.05) increased the stem length and seedling weight. Chlorophyll in leaves increased rapidly when seedlings were radiated by blue light but no significant (p > 0.05) difference was observed among light radiated seedlings after 96-h cultivation. β-Carotene content of LED radiated leaves was significantly (p < 0.05) higher in red light (54.47 ± 2.35 μg/g) group than in the others. TEAC value of ethanol and acetone extracts (50 mg/mL) of 240 pieces of red light radiated seedlings cultured for 96 h reached 106.48 and 81.68 μM, respectively, were higher than the other treatments. In conclusion, the contribution of red light to significant β-carotene expression and antioxidant activity for nutrition and health benefits and blue light to seedling weight and chlorophyll induction of radiated pea seedlings are emphasized.
Whole grain products are recommended for healthy diets as being recognized sources of dietary fiber and antioxidant substances. In the present study, four cereals including barley, pearl millet, rye and sorghum which are adapted to the growing conditions in the United Arab Emirates were evaluated in terms of their composition of dietary fiber, resistant starch, minerals and total phenols and antioxidant properties. Antioxidant activity was evaluated on the basis of scavenging capacity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and 2,2′-azino-di-[3-ethylbenzthiazoline sulphonate] (ABTS+ radical cations). The adapted grains exhibited better nutritional quality compared to commercial hard and soft wheat flours, the main ingredients in grain-based food products. They were significantly rich in resistant starch, soluble and insoluble dietary fibers, minerals and antioxidants. Barley had the highest levels of phosphorus, calcium, potassium, magnesium, sodium, copper, and zinc, and the second highest content of iron following millet. Sorghum was exceptionally high in antioxidant activities followed by millet and barley. The antioxidant properties of the three grains were comparable to butylated hydroxytoluene. The nutritional data suggest that the selected grains, particularly barley and sorghum, hold promise as healthy food ingredients.
A new simple and sensitive analytical spectrophotometric method is developed for the determination of ascorbic acid reduces methyl viologen to form a stable blue coloured free radical ion. This method has a sensitivity and lower limit detection of 0.1mugml(-1) of ascorbic acid (0.1ppm) which is comparable to the flow injection analysis reported earlier. Beer's law is obeyed over the concentration range of 1.0-10mugml(-1) of ascorbic acid per 10ml of the final solution (0.1-1.0mugml(-1)) at 600nm. The molar absorptivity and Sandell's sensitivity were found to be 1.5x10(5)+/-100lmol(-1)cm(-1) and 0.001mugcm(-2), respectively. The method has been applied to the determination of ascorbic acid in food, pharmaceuticals and biological samples.
Plants are an important source of essential nutrients and health-beneficial components that are crucial for human life. Because the intake of these phytochemicals is not always adequate, the resources of plant biotechnology are being used to enhance the nutritional quality of our plant-based food supply. Various improvement strategies are feasible, depending on whether the phytochemical target is a major or minor constituent. Recent efforts in gene discovery and functional genomics are providing the necessary understanding to develop and evaluate different approaches to manipulate phytochemical composition.
In this study four cultivars of lentil originating from Spain were examined: cv Paula, cv Agueda, cv Almar and cv Alcor. Since consumption of these seeds after heat treatment and as sprouts has been popularised, the impact of cooking (up to 30 min) and germination process (in dark, at 25 degrees C, for up to 4 days) on peroxyl radical-trapping capacity (PRTC) and Trolox-equivalent antioxidant capacity (TEAC) of the processed seeds was addressed. Also, changes in the content of low-molecular-weight antioxidants (LMWA) and soluble proteins in the course of cooking and germination were studied. The analyzed LMWAwere: total phenolics, tocopherols (alpha-T, beta-T, gamma-T, delta-T), reduced glutathione, and L-ascorbic acid. On the basis of the results obtained, the contribution of LMWA and soluble proteins to the PRTC and TEAC of raw, cooked, and germinated lentil seeds was calculated by multiple mean values for the content of investigated compounds and their relative potential with respect to Trolox. The results showed avery high molar percentage contribution of phenolic compounds and low contribution of tocopherols, glutathione, soluble proteins, and ascorbate (only in germinated seeds) to the total TEAC and total PRTC calculated as a sum of data provided for phosphate-buffered and 80% methanolic extracts of raw and processed lentil seeds.
Plants have evolved highly complex sensory mechanisms to monitor their surroundings and adapt their growth and development
to the prevailing environmental conditions. The integration of information from multiple environmental cues enables the co‐ordination
of development with favourable seasonal conditions and, ultimately, determines plant form. Light signals, perceived via the
phytochrome, cryptochrome and phototropin photoreceptor families, are especially important environmental signals. Redundancy
of function among phytochromes and their interaction with blue light photoreceptors enhance sensitivity to light signals,
facilitating the accurate detection of, and response to, environmental fluctuations. In this review, current understanding
of Arabidopsis phytochrome functions will be summarized, in particular, the interactions among the phytochromes and the integration of light
signals with directional and temperature sensing mechanisms.
The degradation of cytokinins in plants is controlled by the flavoprotein cytokinin dehydrogenase (EC 1.5.99.12). Cytokinin dehydrogenase from maize showed the ability to use oxidation products of guaiacol, 4-methylcatechol, acetosyringone and several other compounds as electron acceptors. These results led us to explore the cability for indirect production of suitable electron acceptors by different quinone-generating enzymes. The results reported here revealed that the electron acceptors may be generated in vivo from plant phenolics by other enzymatic systems such as peroxidase and tyrosinase/laccase/catechol oxidase. Histochemical localization of cytokinin dehydrogenase by activity staining and immunochemistry using optical and confocal microscopy showed that cytokinin dehydrogenase is most abundant in the aleurone layer of maize kernels and in phloem cells of the seedling shoots. Cytokinin dehydrogenase was confirmed to be present in the apoplast of cells. Co-staining of enzyme activity for laccase, an enzyme poised to function on the cell wall in the apoplast, in those tissues suggests a possible cooperation of the enzymes in cytokinin degradation. Additionally, the presence of precursors for electron acceptors of cytokinin dehydrogenase was detected in phloem exudates collected from maize seedlings, suggestive of an enzymatic capacity to control cytokinin flux through the vasculature. A putative metabolic connection between cytokinin degradation and conversion of plant phenolics by oxidases was proposed.
Two experimentally important species, Solanum lycopersicon Mill. and Nicotiana benthamiana L., were propagated in vitro under low light (50 micromol m(-2) s(-1)) and transferred to HL (200 micromol m(-2) s(-1)) under a protocol previously developed for grapevine and chestnut. Compared with photooxidative stress parameters already tested in those species, imaging of hydrogen peroxide and superoxide revealed an accumulation on d2-3 and d6 in S. lycopersicon and d1-2 and d5-7 in N. benthamiana. SOD, CAT and APX activities matched ROS accumulation. The expression of the respective transcripts showed a significant increase on d1 in S. lycopersicon while in N. benthamiana a bimodal pattern was found, with peaks on d2 and d7. These results, together with the relative timing of root expansion and new leaf emergence, indicate that these two apparently similar species display different strategies when responding to light stress, evidencing further the uniqueness of the response of each species. The behaviour of N. benthamiana falls closely into the pattern already reported for wood species including grapevine.
Harmonised tripartite guideline Validation of analytical procedures: Text and methodology Q2(R1) Available from: http://www
ICH (2005). Harmonised tripartite guideline. Validation of analytical procedures: Text
and methodology Q2(R1). Available from: http://www.ich.org/LOB/media/
MEDIA417.pdf.
The contribution of photosynthesis to the red light
- I Baroli
- G D Price
- M R Badger
- S Caemmerer
Baroli, I., Price, G. D., Badger, M. R., & Caemmerer, S. (2008). The contribution of
photosynthesis to the red light. Plant Physiology, 146, 737-747.
Solanom lycopersicon Mill. and Nicotiana benthamiana L. under high light show distinct responses to antioxidative stress
- L C Carvalho
- S Santos
- B J Viela
- S Amancio
Carvalho, L. C., Santos, S., Viela, B. J., & Amancio, S. (2008). Solanom lycopersicon Mill.
and Nicotiana benthamiana L. under high light show distinct responses to antioxidative stress. Journal of Plant Physiology, 165, 1300-1312.
Tissue localization of cytokinin dehydrogenase in maize: Possible involvement of quinone species generated from plant phenolics by other enzymatic systems in the catalytic reaction
- P Giliberto
- J Frebortova
- L Luhova
- K D Bilyeu
- J T English
- I Frebort
Giliberto, P., Frebortova, J., Luhova, L., Bilyeu, K. D., English, J. T., & Frebort, I. (2005).
Tissue localization of cytokinin dehydrogenase in maize: Possible involvement
of quinone species generated from plant phenolics by other enzymatic systems
in the catalytic reaction. Plant Cell Physiology, 46, 716-728.
Blue light dose-responses of leaf photosynthesis, morphology, and chemical composition of Cucumis sativus grown under different combinations of red and blue light
- S W Hogewoning
- G Trouwborst
- H Maljaars
- H Pooter
- W Van Ieperen
- J Harbinson
Hogewoning, S. W., Trouwborst, G., Maljaars, H., Pooter, H., van Ieperen, W., &
Harbinson, J. (2010). Blue light dose-responses of leaf photosynthesis,
morphology, and chemical composition of Cucumis sativus grown under
different combinations of red and blue light. Journal of Experimental Botany,
61, 3107-3117.
Harmonised tripartite guideline. Validation of analytical procedures: Text and methodology Q2(R1)
- Ich
ICH (2005). Harmonised tripartite guideline. Validation of analytical procedures: Text
and methodology Q2(R1). Available from: http://www.ich.org/LOB/media/
MEDIA417.pdf.