Red LED Photobiomodulation Enhances Metabolic Activity in Cultured Human Pericytes

This study evaluated the influence of red (630–640 nm) and blue (450 nm) light-emitting diodes (LED) lights on the changes in antioxidant constituents, activity, volatile compounds, and overall acceptability of Coriander leaves (Coriandrum sativum) during post-harvest storage. Coriander leaves are harvested at commercial maturity, packed in polyethylene terephthalate punnets, and exposed for 2 h to the red LED or blue LED lights separately during storage at 5°C and 85% RH up to 9 days. Coriander leaves exposed to the white light (2 h) and continuous darkness served as controls. Samples were removed from cold storage at 3, 6, and 9 days to determine the antioxidant constituents, their activity, retention of volatile compounds, and overall acceptance. Coriander leaves exposed to red and blue LED lights for 2 h showed a commercially allowable mass loss of up to 9 days compared to the other treatments. Compared to those exposed to red LED light (2 h) and the control, leaves exposed to blue LED light for 2 h and stored for 3–9 days showed a reduction in colour change (ΔE). The β-carotene content significantly peaked at 44.55% on day 6 in coriander leaves exposed to the red LED light. However, leaves exposed to blue and red LED light showed an increase in total phenolic content by 9.34 and 6.39% on day 9, respectively. Exposure to blue LED lights increased the antioxidant activities (DPPH, ABTS, and FRAP), quercetin content, and the concentration of typical coriander aroma, 2-tridecenal, 2-dodecenal, (E), and Z-9-19 hexadecenal on day 9. Coriander leaves exposed to blue LED light (2 h) and stored up to day 9 scored a higher acceptance level by the panellists. Thus, blue light LED treatment during post-harvest storage can be recommended to retain the antioxidant property of coriander leaves.

As an alternative to conventional lighting systems, light emitting diode (LED) has been demonstrated to be an artificial flexible lighting source for commercial micropropagation. The objective of this study was to determine the effects of different LED light quality on in vitro shoot proliferation and growth of Vanilla planifolia. To evaluate shoot proliferation, axillary bud cuttings (3 to 5 mm in diameter) of V. planifolia were used as explants and cultivated on Murashige and Skoog basal medium supplemented with 9.55 µM of 6-benzylaminopurine. To evaluate in vitro growth, unrooted shoots (2 cm in length) were used as explants cultivated on Murashige and Skoog basal medium without plant growth regulators. All explants were exposed to a 16 h photoperiod for 60 days under five different lights: fluorescent lamp, white LED, blue LED, red LED and blue plus red LED mixtures (Blue + Red = 1:1). The results indicated a clear increase in the number of shoots per explant under Fluorescent Lamp, White LED and Blue+Red LED light; these treatments produced more than 10 shoots. Shoot length was more than 3 cm in cultures under Blue, Red and Blue+Red (1:1) LEDs, and less than 3 cm in Fluorescent Lamp and White LEDs. Our results also showed that fresh weight, dry weight and dry matter were greatest in shoots under Blue+Red LED light. For shoot growth, plant height, number of leaves, number and length of roots, fresh weight, dry weight, dry matter and chlorophyll content were greater under Fluorescent Lamp and White LED. In conclusion, White or Blue+Red LED light may be used as an alternative light source for shoot proliferation, while White LED may be used for growth in vitro. These results demonstrate the effectiveness of light qualities using LEDs for micropropagation of V. planifolia. Key words: Light quality, micropropagation, orchid, chlorophyll.

Ascorbate is one of the most abundant soluble antioxidants in the plant. Multiple functions of ascorbate in photo protection have been proposed, including scavenging of reactive oxygen species generated by oxygen photoreduction and photorespiration. There is still unclear information relation to LED light with Ascorbate biosynthesis and metabolism, yellowing, chlorophyll content, and ethylene production in broccoli florets. The effect of light-emitting diodes (LED) light on ascorbate (AsA) biosynthesis and metabolism in broccoli (Brassica oleracea L. var. Italica) cultivar “Ryokurei” were studied using red (660 nm), blue (470 nm) and white LED lights as the light source and also no light treatment as the control. Gene expression involved in the biosynthesis and metabolism of AsA, AsA content, color, chlorophyll content and ethylene production rate on the postharvest broccoli were observed in 4 days. The result showed that after two days, red light treatment significantly (p < 0,05) delayed the decrease of ascorbate content. The result was supported by observations using Real-Time Quantitative RT-PCR showed that red light treatment can suppress mRNA level of BO-APX1, BO-APX2, and BO-sAPX on the third day. Observation of BO-GLDH mRNA level was increased in the third-day exposure of red LED light. Therefore red LED light showed up-regulated AsA biosynthesis transcriptional level. Enzymes which possibility responsible for AsA metabolism and biosynthesis in a row were Ascorbate Peroxide (APX) and L-Galactono-1,4-Lactone Dehydrogenase (GLDH). The regulation of this gene expression might contribute to the suppression of AsA reduction by red LED light treatment in broccoli. Red LED also showed suppression of yellowing and decline the chlorophyll content in postharvest broccoli florets. Keywords: ascorbate, LED; broccoli; gene expression; real-time quantitative RT-PCR.

Introduction. Anthocyanins are a group of flavonoids, and their synthesis is influenced by external and internal factors such as light, temperature, phytohormones and sugar concentration. A high anthocyanin concentration, which is related to redder coloration, is one of the factors of high-quality fruit. The effects of LED irradiation on the anthocyanin concentration and enzymatic and antioxidant activities in apple skin were studied. Materials and methods. Nine 8-year-old ‘Tsugaru’ apple trees (Malus domestica Borkh.) grafted onto Malling26 (M.26 EMLA) rootstocks planted in 45-L plastic pots covered with polyvinyl film (90% transmittance) and grown in a greenhouse were used. The effects of red or blue light-emitting diode (LED) irradiation on anthocyanin accumulation, the expression of MdMYB10 and UDP-glucose-flavonoid 3-O -glucosyltransferase (MdUFGT ) and superoxide anion radical (O scavenging activity in the skin of ‘Tsugaru’ apples were investigated under early heating cultivation in a greenhouse. Results and discussion. The anthocyanin concentrations in red LEDtreated apples were increased compared with those of the blue LEDtreated apples and the untreated control at 130 days after full bloom (DAFB). The relative expression of MdMYB10 and MdUFGT genes at 130 DAFB was also highest in the skin of apples treated with red LED light. The skin of apple fruits treated with red or blue LED light showed significantly low EC50 values. Conclusion. These results suggest that red LED irradiation may be used in a controlled environment such as a greenhouse to increase the anthocyanin synthesis and antioxidant activity in apple skin.

Artificial light, in terms of its intensity and color, is of significant importance for the performance of laying hens. In this study, the efforts were made to evaluate the effect of different light-emitting diode (LED)-based light colors on production performance, welfare, and egg quality attributes of Lohmann LSL lite hens in an open-sided house. For this, 200 commercial laying hens were distributed into 4 treatment groups, having 5 replicates of 10 birds each. The treatments included different LED colors, i.e. white, monochromatic green, monochromatic red, and dichromatic red?green. Green light significantly increased body weight as compared to other LED light colors. Egg number and overall egg production percentage were higher in birds maintained under red LED. Egg mass was better under white light as compared to the rest of the treatments. Feed conversion ratio per dozen eggs and kg egg mass were better in birds reared under red and white LED lights, respectively. Initially, footpad dermatitis and feather cleanliness scores were not influenced by the light color; however, significant effects were recorded at 50 weeks of age. Hormonal profiles of laying birds also revealed several differences at 50 weeks of age under different LED light colors. Keeping in view the overall production performance and considering the fitness of the bird, red LED light may best serve the purpose.

Sesamin is a major lignan constituent of sesame seeds and beneficial to human health. We previously reported that sesamin is contained in leaves as well as seeds of sesame and proposed that sesame leaves could be a new sesamin source. Growth and constituents of plants are affected by light wavelength. In this study, growth and leaf sesamin content of sesame variety ‘Gomazou’ were investigated in plants grown under continuous white fluorescent and monochromatic red or blue light emitting diode (LED) light. Under red LED light, plants developed pale-green, epinastic leaves. Compared with white fluorescent light, red LED light promoted stem elongation 1–3 weeks after sowing but retarded it 3–5 weeks after sowing. Under blue LED light, plants exhibited interveinal necrosis in the leaf blades and excessive stem elongation occurred irrespective of plant age. Leaf yields were lower in plants grown under red and blue LED lights relative to those under white fluorescent light. Blue LED light increased leaf sesamin content by 2.0 and 4.5 times compared with white fluorescent and red LED lights, respectively. From these results, we concluded that blue (LED) light may be effective at producing sesamin-rich leaves if the unfavorable morphological changes and reduction in growth can be prevented.

Effect of light intensity and wavelengths on ascorbic acid content and the antioxidant system in tomato fruit grown in vitro

The effects of light generated by red and blue light-emitting diodes (LEDs) on callus induction from protocorm-like body (PLB) segments, callus proliferation and PLB formation from callus in Cymbidium orchid were investigated. The cultures were placed in 'LED PACK 4' incubators under different ratios of red and blue LED light (100% red LEDs, 75% red LEDs+25% blue LEDs, 50% red LEDs+50% blue LEDs, 25% red LEDs+ 75% blue LEDs, and 100% blue LEDs) at 45μmol m-2s-1 with a 16-h photoperiod or put under plant growth fluorescent (PGF) light with the same light intensity and photoperiod. Among the treatments, 100% red LEDs was the most effective for callus induction from PLB segments. Callus proliferation was best in the 75% red LEDs+25% blue LEDs treatment but was not significantly different from that in PGF light. The highest PLB formation from callus was obtained in 25% red LEDs+75% blue LEDs. The results suggested that LEDs are the effective light source for callus induction, callus proliferation and PLB formation from callus in Cymbidium orchid.

The effects of red light-emitting diode (LED) light irradiation (630 nm, 0.5 W/m2) and melatonin (10-8 and 10-7 M) on oxidative stress and physiological responses in abalones exposed to high temperatures (28°C) were investigated. Changes in messenger RNA (mRNA) expressions of melatonin receptor (MT-R), heat shock protein 70 (HSP70), and antioxidant enzymes, as well as alterations in H2O2 levels in the hemolymph, were examined. The results revealed that high-temperature-stressed abalones treated with melatonin injections or exposed to red LED light showed a significant increase in MT-R mRNA expression, while HSP70 mRNA expression decreased. Notably, HSP70 mRNA expression levels in the red LED light-irradiated group were similar to those in the group injected with 10-8 M melatonin after 24 h exposure. Abalones treated with melatonin at 20°C or irradiated with red LED light exhibited decreased H2O2 levels and reduced antioxidant enzyme mRNA expression compared with those of the control group. However, the high-temperature environment induced oxidative stress in abalones, leading to increased antioxidant enzyme mRNA expression compared with that under 20°C conditions. Moreover, abalones exposed to high-temperature stress exhibited hepatopancreatic DNA damage, which was attenuated by melatonin treatment or red LED light irradiation. Hence, red LED light reduces oxidative stress, boosts antioxidant enzymes, and alleviates DNA damage in high-temperature-stressed abalones, akin to 10-8 M melatonin treatment. Therefore, considering the practical challenges of continuous melatonin administration to abalones, utilizing red LED light emerges as a practical, effective alternative to protect abalones from oxidative stress compared to 10-8 M melatonin treatment.

Effect of the combination of ethylene and red LED light irradiation on carotenoid accumulation and carotenogenic gene expression in the flavedo of citrus fruit

Effect of red and blue LED light irradiation on ascorbate content and expression of genes related to ascorbate metabolism in postharvest broccoli

Dwarf sour cherry (Prunus cerasus L.) is a cold-hardy, short-statured pie cherry released by the University of Saskatchewan. The cherries have higher sugar and acid contents than the pie cherries and may have market potential. In this study, we assessed the influence of blue and red light-emitting diodes (LEDs) on sour cherry ‘Carmine Jewel’ over a 3-week storage period in a walk-in cooler maintained at a temperature of − 2 °C. Both red and blue LED treatments increased the sour cherry rate of mass loss and soluble solid contents by 0.5−1.5 °Brix and pH by 0.05, but decreased the total acidity by 0.3% after 24 days of storage. In the meantime, LEDs influenced the color of the sour cherry skin. Compared to the dark treatment, the sour cherries had a lighter skin color (lower lightness (L*)). The red LED also significantly increased the red-blue (a*) parameters, resulting in a redder and brighter color. However, red LEDs might negatively influence the firmness, whereas blue LEDs did not significantly affect the firmness of sour cherries. For the secondary metabolites, both LEDs caused a significant increase in total phenolics in sour cherries after 24 days of storage. Blue LEDs appeared to influence this increase during the early storage period, specifically on days 3 and 6. Both red and blue LEDs consistently increased the anthocyanin content and ascorbic acid levels during storage, with more than 8 mg/L anthocyanins and 1−20 μg/mL ascorbic acids compared to the content under dark treatment after storage. The characteristics suggest that red and blue LEDs may play essential roles in the changes of primary and secondary metabolism. Anthocyanin compounds in sour cherries, including cyanidin-3-rutinoside, cyanidin-3-glusosylrutinoside, and cyanidin-3-glucoside, showed no changes in the dark treatment but were significantly increased under red and blue LEDs, with the red impact being larger. Cyanidin-3-sophoroside increased under dark treatment, but both LEDs had a more significant influence on its content, especially under the red LEDs. Neither red nor blue LEDs significantly influenced the microbial populations, although there was more than a 1.5 (lg (CFU/g)) increase in mold and yeast growth during storage. Similarly, both LEDs increased weight loss, which is not preferred for postharvest storage. This indicates the need to optimize radiation duration and light intensity in further studies. Therefore, LEDs can help improve certain qualities of sour cherries, and further adjustments are needed to achieve additional improvements.

To clarify the response of net photosynthetic rate (Pn), stomatal conductance ( g S ), transpiration rate (Tr), and leaf intercellular CO 2 concentration (Ci) to irradiance on the adaxial and abaxial sides of mature and young strawberry leaves using blue, green, and red light-emitting diodes (LEDs), irradiation from a short distance was investigated using ‘Tochiotome’. Light–photosynthetic response curves of the adaxial side of mature leaves were not different among LED treatments. However, those of the adaxial side of young leaves irradiated with red LEDs were less than those of other LED treatments. Pn of the abaxial side of mature leaves was 42% to 71% of the abaxial side. In young leaves, Pn of the abaxial side was 17% to 68% of the adaxial side. Moreover, light–transpiration response curves were different with LED treatments. Ci and Tr under blue and green LEDs were greater than those under red LEDs. This indicates that blue and green lights affected the stomatal opening. In contrast, red LEDs decreased Ci more than other LED treatments. In addition, reactions of the adaxial side of young leaves under blue and red LEDs were seen not only in ‘Tochiotome’, but also in ‘Sachinoka’ and ‘Eran’, which indicates that the photosynthetic reactions of blue light and red light are common characteristics of the strawberry. Therefore, red LEDs promoted the photochemical reaction and activated the CO 2 fixation system. Based on the results of this study of short-distance lighting with LEDs in strawberry production, irradiance of the abaxial side of leaves by blue or green LEDs might improve more assimilates in young leaves compared with red LEDs to increase strawberry yield.

The objective of this study was to determine the effects of different light-emitting diode (LED) light sources on the growth of upland cotton (Gossypium hirsutum L.) plantlets. Shoot bud apex cuttings of upland cotton (1.0 cm) were transplanted on Murashige and Skoog (MS) basal medium supplemented with 0.1 mg/l 6-benzyladenine (BA) and 0.5 mg/l naphthalene acetic acid (NAA) and cultured in vitro for 45 days. They were exposed to 50 μmol m−2 s−1 photosynthetic photon flux (PPF) and a 12-h photoperiod under six different lights: fluorescent lamp (CON), monochromatic blue LED (B), three blue and red LED mixtures (B:R = 3:1, 1:1, 1:3) and monochromatic red LED (R). The effects of the six light sources on growth and morphogenesis of upland cotton plantlets grown in vitro were investigated. Fresh weight, dry weight, stem length and second internode length were greatest in plantlets cultured under the B:R = 1:1 blue and red LED light, followed by blue LED light, and they were lowest in plantlets cultured under a fluorescent lamp. Chlorophyll content, leaf thickness, palisade tissue length, leaf and stomata area were highest in plantlets cultured under blue LED light. Root activity, sucrose, starch and soluble sugar contents were highest in plantlets cultured under red LED light. Our results showed that larger, healthier plantlets and a greater biomass of upland cotton were produced in the presence of red LED supplemented with a quantity of blue LED light. Blue and red LED (B:R = 1:1) was the most suitable light for the growth of upland cotton plantlets in vitro, and it may be used as alternative light source for an upland cotton culture system.

The effect of light quality on seed germination, seedling growth and selected biochemical properties of Stevia rebaudiana Bertoni