LED Light Treatment Research Articles

Intra-canopy LED lighting outperformed top LED lighting in improving tomato yield and expression of the genes responsible for lycopene, phytoene and vitamin C synthesis

Greenhouses located at high latitudes and in cloudy areas often experience a low quality and quantity of light, especially during autumn and winter. This low daily light integral (DLI) reduces production rate, quality, and nutritional value of many crops. This study was conducted on Sakhiya RZ F1 tomato plants to evaluate the impact of LED lights on the growth and nutritional value of tomatoes in a greenhouse with low daily light due to cloudy weather. The treatments included LED growth lights in three modes: top lighting, intra-canopy lighting, and combined top and intra-canopy lighting. The results showed that although the combined top and intra-canopy lighting reached the maximum increase in tomato yield, exposure to intra-canopy LED lighting alone outperformed in tomato fruit yield increase (28.46%) than exposure to top LED lighting alone (12.12%) when compared to no supplemental lighting during the entire production year. Intra-canopy exposure demonstrated the highest increase in tomato lycopene (31.3%), while top and intra-canopy lighting exhibited the highest increase in vitamin C content (123.4%) compared to the control. The LED light treatment also had a very positive effect on the expression of genes responsible for metabolic cycles, including Psy1, LCY-β, and VTC2 genes, which had collinearity with the increase in tomato fruit production.

The Influence of Different LED Light Treatments on the Growth and Salt Stress Tolerance of Cauliflower Microgreens In Vitro

The aim of this study was to investigate the effects of different LED lights on the growth of cauliflower microgreens and to determine which combination of LED light best increases tolerance to salt stress and promotes the growth and accumulation of secondary antioxidants in the presence of salt stress in vitro. Plants were grown in a growth chamber under different LED light treatments (red light, blue light, a combination of red and blue light, and cool white light) and in MS media with different NaCl concentrations (0, 50, and 100 mM). The effects of the different light qualities and salt stress conditions on growth, content of photosynthetic pigment, flavonoids, phenol, proline, and antioxidant enzyme activity were measured. The best treatments for microgreen development, according to the data, were those that combined red and blue light. In addition to increasing stress tolerance and enabling plant growth at a lower salt concentration (50 mM NaCl), the combination of blue and red light also enhanced the synthesis and accumulation of secondary metabolites and the antioxidant potential of microgreens grown in vitro, which may have nutritional and pharmaceutical value.

Genome-wide identification and expression analysis of the cryptochromes reveal the CsCRY1 role under low-light-stress in cucumber.

Low-light-stress is a common meteorological disaster that can result in slender seedlings. The photoreceptors play a crucial role in perceiving and regulating plants' tolerance to low-light-stress. However, the low-light-stress tolerance of cucumber has not been effectively evaluated, and the functions of these photoreceptor genes in cucumber, particularly under low-light-stress conditions, are not clear. Herein, we evaluated the growth characteristics of cucumber seedlings under various LED light treatment. The low-light-stress tolerant cucumber CR and intolerant cucumber CR were used as plant materials for gene expression analysis, and then the function of CsCRY1 was analyzed. The results revealed that light treatment below 40 μmol m-2 s-1 can quickly and effectively induce low-light-stress response. Then, cucumber CR exhibited remarkable tolerance to low-light-stress was screened. Moreover, a total of 11 photoreceptor genes were identified and evaluated. Among them, the cryptochrome 1 (CRY1) had the highest expression level and was only induced in the low-light sensitive cucumber CS. The transcript CsaV3_3G047490.1 is predicted to encode a previously unknown CsCRY1 protein, which lacks 70 amino acids at its C-terminus due to alternative 5' splice sites within the final intron of the CsCRY1 gene. CRY1 is a crucial photoreceptor that plays pivotal roles in regulating plants' tolerance to low-light stress. In this study, we discovered that alternative splicing of CsCRY1 generates multiple transcripts encoding distinct CsCRY1 protein variants, providing valuable insights for future exploration and utilization of CsCRY1 in cucumber.

Effects of light qualities on growth and physiological-biochemical traits of Scutellaria baicalensis.

Canopy spectral composition significantly affects growth and functional traits of understory plants. In this study, we explored the optimal light condition suitable for enhancing Scutellaria baicalensis's yield and quality, aiming to provide scientific reference for the exploitation and utilization of medicinal plant resources in the understory of forests. We measured the responses of growth, morphology, biomass allocation, physiological traits, and secon-dary metabolites of S. baicalensis to different light qualities. S. baicalensis was cultured under five LED-light treatments including full spectrum light (control), ultraviolet-A (UV-A) radiation, blue, green, and red light. Results showed that UV-A significantly reduced plant height, base diameter, leaf thickness, leaf area ratio, and biomass of each organ. Red light significantly reduced base diameter, biomass, effective quantum yield of photosystem Ⅱ (ФPSⅡ), and total flavonoid concentration. Under blue light, root length and total biomass of S. baicalensis significantly increased by 48.0% and 10.8%, respectively, while leaf number and chlorophyll content significantly decreased by 20.0% and 31.6%, respectively. The other physiological and biochemical traits were consistent with their responses in control. Our results suggested that blue light promoted photosynthesis, biomass accumulation, and secondary metabolite synthesis of S. baicalensis, while red light and UV-A radiation negatively affected physiological and biochemical metabolic processes. Therefore, the ratio of blue light could be appropriately increased to improve the yield and quality of S. baicalensis.

Effect of LED light on the production of fruiting bodies and nucleoside compounds of Cordyceps militaris at different growth stages of solid-state fermentation

BackgroundTimely harvesting of Cordyceps militaris fruiting bodies and their bioactive compounds can reduce production costs. This study examined the effects of LED treatments on the production of fruiting bodies and nucleoside compounds in C. militaris at different growth stages of solid-state fermentation. MethodsC. militaris was grown on oats under different LED light treatments. Harvested samples were divided into fruiting bodies and fermented oats to dry, grind, extract, and determine the contents of adenosine, cordycepin, and pentostatin during cultivation by high-performance liquid chromatography. Significant FindingsThe highest fruiting bodies yield (6.20 g dw/bottle), biological efficiency (92.75 %), adenosine (2.22 mg/g dw), and cordycepin (2.57 mg/g dw) content in fruiting bodies were achieved on the 56th day under T5 white, LED blue light, LED blue light, and LED red light, respectively. LED white (1.31 mg/g dw), LED blue (1.23 mg/g dw), and LED red (1.25 mg/g dw) lights during days 35 to 42 resulted in the highest pentostatin content in fruiting bodies. Optimal yields of C. militaris fruiting bodies and their nucleoside compounds can be achieved through appropriate LED lighting and timely harvesting.

Blue LED light treatment of pregnant mares is not detrimental to gonadal development in their offspring

A light program transmitted via blue LED light directed at one eye from individual light masks (Equilume, Kildare, Ireland) to pregnant mares from the middle of December onwards advanced the onset of foaling with birth of mature and healthy foals, but they were slightly smaller than foals from untreated control pregnancies (Lutzer et al., Domestic Anim Endocrinol 2022;78:106675). Differences, however, equilibrated within the first year of life. In this study we followed the hypothesis that light treatment of pregnant mares is without detrimental effects on body size and gonadal development of offspring after puberty. A total of 47 warmblood horses born and raised on the same stud farm to blue LED light-treated (17 males and 9 females) or control mares (14 males and 9 females) were included. At 24 months of age, their body weight, height at withers and cannon bone circumference was determined. In males, the external genitalia were examined, testis size was measured by transcutaneous ultrasound. The total testicular volume (TTV) was calculated. In females, a transrectal ultrasound examination of the genital tract was performed, the presence of corpora lutea was detected via plasma progesterone concentration and the antral follicle count (AFC) was assessed. Statistical comparisons weremade by analysis of variance (general linear model) with group (blue light vs. control) and sex (male vs. female) as between subject factors (IBM SPSS 27). Results are given as mean ± SEM. There were no group or sex differences with regard to bodyweight or height at the withers. The cannon bone circumference was larger in male vs. female horses (p<0.001) but not affected by blue light treatment during pregnancy. Testes were classified as normal in size and location (Love et al., J Reprod Fertil Suppl 1991;44:99-105) in 13 of 17 blue light and 11 of 14 control colts (n.s., chi2 analysis). The TTV was 232±14cm3 in the blue light and 218±11cm3 in the control group (n.s.). Abnormal testicular development was diagnosed in 7 males with unequal testicular size in 3 blue light and 2 control animals, both testes too small (1 blue light) or unilaterally cryptorchid (1 control). In females, no abnormalities were present. A corpus luteum (progesterone >1ng/ml) was present in 8 / 9 females from the blue light and 5 / 8 from the control group. The AFC was 20.6±2.5 in blue light and 22.1±3.7 in control females (n.s.). Results demonstrate that blue LED light treatment of pregnant mares has no detrimental effects on body and genital tract development of their offspring at two years of age.

Effect of different LED wavelengths on growth, chlorophyll and anthocyanin content of purple-red pakchoi (Brassica rapa chineensis) in indoor vertical farming

Understanding the effects of different light wavelengths on plant growth and the accumulation of essential nutrients like antioxidants is critical for obtaining optimal light conditions for the production of high-quality vegetables in indoor vertical farming. Purplered pakchoi (Brassica rapa chineensisis) is a fast-growing brassiceous vegetable. This vegetable is known to have health-promoting properties due to anthocyanin, which is a crucial antioxidant in the diet. This crop was used to evaluate the effects of red (RL), blue (BL), and green (GL) wavelengths on plant morphology, relative chlorophyll content, and phytochemical accumulation (anthocyanin). Light treatments consisted of three different wavelength combinations: a) full spectrum, white light (WL) as a control (the proportions of RL, BL and GL wavelengths were 42%, 15% and 43%, respectively); b) combination RL81BL19 (the proportions of RL and BL wavelengths were set at 81% and 19%, respectively); and c) combination RL70BL21GL9 (the proportions of RL, BL and GL wavelengths were set at 70%, 21% and 9%, respectively). The experiment was carried out in the LED Light Research Lab (MARDI, Serdang), a walk-in chamber with a 12-hour photoperiod. The temperature, CO2, and relative humidity levels in the LED light lab were kept under control. Plant width and height were found to be most prominent in plants exposed under RL81BL19 LED light, followed by RL70BL21GL9, while plants grown under WL were relatively small. Purple-red pakchoi exposed to a combination of RL and BL, supplemented with GL light treatment, had a slightly smaller plant height and width than plants exposed to RL81BL19 light treatment. Similar results were obtained in terms of shoot fresh and dry weight, with the RL81BL19 having the highest shoot fresh and dry weight, followed by the RL70BL21GL9 and WL light exposure plants. Furthermore, when compared to other treatments, purple-red pakchoi treated with RL81BL19 light had a significantly higher content (p&lt;0.05) of chlorophyll and anthocyanin. This finding indicated that GL light treatment has no direct effect on overall growth, chlorophyll accumulation, or anthocyanin content in purple-red pakchoi. This study found that the RL81BL19 wavelength is the best LED light treatment for purple-red pakchoi production in indoor vertical farming.

LED omics in Rocket Salad (Diplotaxis tenuifolia): Comparative Analysis in Different Light-Emitting Diode (LED) Spectrum and Energy Consumption.

By applying three different LED light treatments, designated as blue (B), red (R)/blue (B), red (R) and white (W) light, as well as the control, the effect on Diplotaxis tenuifolia phenotype (yield and quality), and physiological, biochemical, and molecular status, as well as growing system resource use efficiency, was examined. We observed that basic leaf characteristics, such as leaf area, leaf number, relative chlorophyll content, as well as root characteristics, such as total root length and root architecture, remained unaffected by different LEDs. Yield expressed in fresh weight was slightly lower in LED lights than in the control (1113 g m-2), with R light producing the least (679 g m-2). However, total soluble solids were significantly affected (highest, 5.5° Brix, in R light) and FRAP was improved in all LED lights (highest, 191.8 μg/g FW, in B) in comparison to the control, while the nitrate content was less (lowest, 949.2 μg/g FW, in R). Differential gene expression showed that B LED light affected more genes in comparison to R and R/B lights. Although total phenolic content was improved under all LED lights (highest, 1.05 mg/g FW, in R/B), we did not detect a significant amount of DEGs in the phenylpropanoid pathway. R light positively impacts the expression of the genes encoding for photosynthesis components. On the other hand, the positive impact of R light on SSC was possibly due to the expression of key genes being induced, such as SUS1. In summary, this research is an integrative and innovative study, where the exploration of the effect of different LED lights on rocket growing under protected cultivation, in a closed chamber cultivation system, was performed at multiple levels.

Analgesic Effectiveness of Physical Therapy Combining the Use of Electromagnetic Fields with Light Radiation Emitted by LEDs along with the Use of Topical Herbal Ointment in Patients with Gonarthrosis

(1) Background: The aim of the study is to evaluate the analgesic effectiveness of a physical therapy regimen that combines the use of an electromagnetic field with light radiation emitted by LEDs, along with the use of Traumeel S ointment, in patients with gonarthrosis. (2) Methods: The study included 90 patients with knee osteoarthritis (grade 2 Kellgren and Lawrence osteoarthritis). They were divided into three groups: Group I, 30 patients treated with magnetic stimulation plus LED therapy; Group II, 30 patients treated with Traumeel S ointment; and Group III, 30 patients treated with magnetic stimulation plus LED therapy with Traumeel S ointment. Pain intensity was assessed using the VAS and Laitinen scales before and after a series of treatments. (3) Results: Significant results in terms of pain reduction before and after treatment were obtained in each of the study groups, as there were significant differences in the VAS pain intensity scores before and after the procedures between the groups. In group I, with electromagnetic field and LED light treatment, the difference was 35.5; in group II, which received Traumeel S® ointment, the difference was 18.5; and in group III, with electromagnetic field and LED light treatment as well as Traumeel S ointment, the difference was 26.5. In the Laitinen scale, the differences were insignificant, although the size distribution was similar. (4) Conclusions: The therapy used in this study showed that magnetic stimulation plus LED therapy and the use of Traumeel S ointment gave positive results in terms of pain reduction in each of the study groups. The strongest analgesic factor seems to be magnetic and LED therapies used separately. Traumeel S in magnetoledophoresis does not work synergistically with the magnetic field of LED light, and even worsens the effect of the therapy used.

Transcriptome Dataset of Strawberry (Fragaria × ananassa Duch.) Leaves Using Oxford Nanopore Sequencing under LED Irradiation and Application of Methyl Jasmonate and Methyl Salicylate Hormones Treatment

This data descriptor introduces a transcriptome dataset of strawberry plant left exposed to an LED light treatment and plant hormones of Methyl Jasmonate (MeJA) and Methyl Salicylate (MeSA). These data consist of a transcriptome dataset (four libraries) obtained from the leaves of strawberry plants treated with LEDs of blue and red spectrums and the hormones of Methyl Jasmonate (MeJA) and Methyl Salicylate (MeSA), which allowed us to conduct a further analysis of the growth and development processes of strawberry plants. In addition, we describe detailed procedures on how the plants were prepared and treated and how the data were generated and processed beforehand. Further analysis of these data will significantly help to improve our understanding of the molecular mechanisms of LED light and MeJA-MeSA in strawberry plants.

Supplemental light with different blue and red ratios in the physiology, yield and quality of Impatiens

• LED 83R:17B increased the cuttings number per Impatiens plant in winter by 35.4%. • Anthocyanin content in Impatiens leaves did not increase with the use of LED. • Impatiens mother plants did not show oxidative stress with LED use and keep quality. • The 83R:17B LED reduced plugs height Impatiens White by 21.3%, even after light off. • The 67R:33B and 83R:17B LEDs, increased average 41.0% trichomes number on leaves. The yield of many ornamental plant species decreases sharply in the fall and winter seasons due to the decrease in solar radiation and temperature. The aim of this study was to verify the response of two Impatiens hybrid hort cultivars Sunpatiens Compact Royal Magenta and Sunpatiens Compact White to LED supplemental light with different ratios of red and blue: 83% red (640-660 nm): 17% blue (460-470 nm), 75% red (640-660 nm): 25% blue (460-470 nm), 67% red (640-660 nm): 33% blue (460-470 nm), and 50% red (640-660 nm): 25% red (620-630 nm): 25% blue (460-470 nm); and control (only natural light). Plants were grown in a nursery greenhouse at Atibaia, SP, Brazil, with day and night air temperature of 28°C and 21°C, respectively. Mother plants were grown with a spacing of 12 cm x 14 cm in plastic boxes (36 cm width x 56 cm length x 14 cm height) with 50% vermiculite and 50% perlite. Lights were placed at 1 m distance from the plants base, emitting a PPFD of 150 µmol m −2 s −1 . The daily supplemental light for 12 hours (6 am to 6 pm) began after mother plants transplant and was maintained for seven months until the end of the experiment. The yield and quality of both mother plants and cuttings collected from them, as well as of the plugs developed after three weeks were evaluated regarding to biometric characteristics, pigments, antioxidant enzymes, stress indicators, photosynthetic activity and trichomes counting. Impatiens response varied according to the growing season. In the winter season, at 202 DAT, the 83R:17B LED light increased in 35.4% the number of cuttings produced per plant compared to the control. The light supplementation with different spectral proportions did not cause oxidative stress of the Impatiens mother plants, maintaining its quality. The performance of Royal Magenta cv. differed from the White cv. regarding to the use of artificial lighting, mainly due to the higher concentration of anthocyanin in leaves of the Royal Magenta cv. The supplemental light effect during the cuttings production of the White cv. continued until the final phase of the plugs production, due to more compact cuttings produced in the 83R:17B LED light treatment.

Light Quality Impacts Vertical Growth Rate, Phytochemical Yield and Cannabinoid Production Efficiency in Cannabis sativa.

Light is one of the most crucial parameters for enclosed cannabis (Cannabis sativa) production, as it highly influences growth, secondary metabolite production, and operational costs. The objective of this study was to investigate and evaluate the impact of six light spectra on C. sativa ('Babbas Erkle Cookies' accession) growth traits and secondary metabolite (cannabinoid and terpene) profiles. The light spectra evaluated included blue (430 nm), red (630 nm), rose (430 + 630 nm, ratio 1:10), purple (430 + 630 nm, ratio 2:1), and amber (595 nm) LED treatments, in addition to a high-pressure sodium (HPS, amber-rich light) treatment as a control. All the LED light treatments had lower fresh mean inflorescence mass than the control (HPS, 133.59 g plant-1), and monochromatic blue light yielded the least fresh inflorescence mass (76.39 g plant-1). Measurement of Δ9-tetrahydrocannabinol (THC) concentration (%) and total yield (g plant-1) showed how inflorescence mass and THC concentration need to be analyzed conjointly. Blue treatment resulted in the highest THC concentration (10.17% m/m), yet the lowest THC concentration per plant (1.44 g plant-1). The highest THC concentration per plant was achieved with HPS (2.54 g plant-1). As with THC, blue light increased cannabigerol (CBG) and terpene concentration. Conversely, blue light had a lesser impact on cannabidiol (CBD) biosynthesis in this C. sativa chemotype. As the combined effects of the light spectrum on both growth traits and secondary metabolites have important ramifications for the industry, the inappropriate spectral design could cause a reduction in cannabinoid production (20-40%). These findings show promise in helping producers choose spectral designs that meet specific C. sativa production goals.

Effect of Use of Different Light Spectrum on Growth Performance and Color Brightness Level of Tiger Barb (Puntius tetrazona)

This study aims to evaluate the effect of light spectrum on growth performance and brightness level of tiger barb (Puntius tetrazona). The research was conducted in January – March 2022 at the Laboratory of Aquatic Animal Physiology, Faculty of Fisheries and Marine Sciences, Padjadjaran University. This study used an experimental method of Completely Randomized Design (CRD) with five treatments and three replications. The treatment consisted of five treatments, namely control (without LED lights), white LED lights (B), red (C), green (D) and blue (E) lights with 12 hours of irradiation. The treatment was given for 60 days. Parameters observed included growth in length and absolute weight, color brightness level, survival rate and water quality (temperature, pH and DO). The results of the study for 60 days of maintenance showed that the best growth parameter was the red LED light treatment with an absolute length growth of 0.57 cm and an absolute weight growth of 0.49 g. The best color quality parameter for tiger barb (Puntius tetrazona) was obtained in the red LED light treatment with an increase in the color score in the Toca color finder (TCF) reaching 1.7 on the body; 2,3 on the pectoral fins; and 2.4 on the tail. The water quality parameter values are in normal conditions (temperature ranges from 27.3-27.9 ◦C; DO ranges from 4.2-5 mg/l; and pH ranges from 6.97-7.65;) so that it is good for the survival rate of tiger barb, namely 100%.

Development of Foals Until One Year of Age When the Dam was Exposed to Blue Monochromatic Light Directed at One Eye During Late Pregnancy

In horses, blue LED light directed at one eye of pregnant mares shortens gestation length and results in the birth of foals with lower wither heights, similar weight and reduced hair length compared to controls. In this study, we have therefore analysed postnatal development of foals born to either blue LED light-treated (n = 20) or control mares (n = 20). Size, weight and hair coat changes were determined for 1 year and heart rate, heart rate variability (HRV) and selected haematology parameters for 1 month. Haematocrit decreased (P < .001) and leukocyte and lymphocyte counts increased (P < .001) but none of the parameters differed between groups. Heart rate (P < .001) and HRV (P < .01) increased until day 6 but did not differ between groups, indicating that foals born to blue LED light-treated mares were mature and healthy. The guard hair was shorter in foals born to treated mares compared to control foals at birth (P < .001) but no differences in hair coat length were observed beyond the age of 2 months. At birth and 6 days thereafter, wither height (P < .01) and elbow to carpus distance (P < .05) of control foals were increased relative to foals born to blue LED light-treated mares. Height differences decreased over time and and for elbow-to-carpus distance there was a time x group interaction (P < .005) In conclusion, blue LED light treatment of pregnant mares is without detrimental effects on postnatal foal growth and development.

Effect of different LED lights on aliphatic glucosinolates metabolism and biochemical characteristics in broccoli sprouts

In this study, various LED lights (white, red, yellow, green, blue and purple) were applied to evaluate their effects on the biochemical parameters, aliphatic glucosinolates synthesis and sulforaphane formation in broccoli sprouts. The length of broccoli sprouts and bulk water content were decreased after LED light treatments, especially white, green, and purple LED lights. The highest contents of ascorbic acid and anthocyanins were recorded in blue LED light treated broccoli sprouts. Green LED light treated sprouts contained the highest contents of ATP, ADP and AMP. Yellow and bule lights resulted in higher glucose content. Yellow, blue, and purple LED lights induced glucoraphanin and glucoerucin accumulation via upregulating aliphatic glucosinolates biosynthetic genes. Yellow LED light caused higher glucoraphanin content than blue LED light, while sulforaphane formation showed no difference; which might be attributed to higher myrosinase activity and its expression as well as lower ESM1 expression under blue LED light.

Effects of The Proportion of The LED Light Red, Blue, and White Colors on Chlorophyll Content and Canopy Area of Pakcoy (Brassica rapa L.)

Abstract&#x0D; Light is the main energy source for plants for the photosynthesis process. In indoor cultivation systems (plant factories), LEDs can be used as artificial light. The dominant light colors absorbed by plants for the photosynthesis process are red and blue, but the proportion of the LED colors used is unknown, so it is necessary to research the proportions of light colors. This study aims to determine the effect of the proportions of red, blue, and white light on the chlorophyll content (SPAD value) and the canopy area of Pakcoy. Pakcoy was planted in a growth chamber and given seven different proportions of light for 12 hours with a lamp total of 60 Watt and light intensity of 2000 lux. This study was conducted for 49 days, and the observations to make once a week. The results showed the proportion of red, blue, and white LED light treatment affects the chlorophyll content and canopy area. The proportions of LED light 30 Watt red, 20 Watt blue, and 10 Watt white produced the highest chlorophyll content (35.0 SPAD value) and canopy area (70.7 cm2). In conclusion, the proportion of red, blue, and white LED light showed significantly different in the growth of Pakcoy.

THE EFFECTS OF LIGHT-EMITTING DIODES (LED) IRRADIATION TREATMENT ON THE POSTHARVEST PRESERVATION AND MICROBIOLOGICAL QUALITY OF STRAWBERRY (Fragaria ananassa) CV. FESTIVAL

Strawberry (Fragaria Ananassa sp.) is non-climacteric, aggregate fruit with a rich source of anthocyanin and vitamin C. However, strawberry has short storage life and is very susceptible to decay and physiological deterioration process. Therefore, emitting the post-harvest LED light to strawberries during cold storage has been studied. This work aimed to evaluate different LED light treatment effects to retain post-harvest quality and microbial quality of the strawberry. The post-harvest parameters that have been used are weight loss, colour, firmness, total soluble solids, titratable acidity, and pH. The microbial parameter such as Escherichia coli count, Salmonella count, total plate count, and mold count would also has been assessed. Strawberries were irradiated under three different LED light types (white, blue and red). Blue and red LED lights have different wavelengths, which are 470 nm and 630 nm. The strawberry fruits were stored at 5ºC in a cold room and study parameter were assessed in 10 days. There were statistically significant differences (p&lt;0.05) between the treatment of weight loss, firmness, pH, and total soluble solid. The best treatment for this experiment is blue LED light which showed the lowest weight loss, retained the colour and delayed firmness loss of the strawberry. This study also proved that blue LED light could reduce the growth of E.coli. In conclusion, LED light produces minimal heat, which improves food safety and preserves post-harvest quality of strawberry.

Study of Postharvest Quality and Antioxidant Capacity of Freshly Cut Amaranth after Blue LED Light Treatment.

Freshly cut vegetables are susceptible to microbial contamination and oxidation during handling and storage. Hence, light-emitting diode technology can effectively inhibit microbial growth and improve antioxidant enzyme activity. In this paper, the freshly cut amaranth was treated with different intensities of blue light-emitting diode (LED460nm) over 12 days. Chlorophyll content, ascorbic acid content, antioxidant capacity, antioxidant enzymes activity, the changes in microbial count, and sensorial evaluation were measured to analyze the effects of LED treatment on the amaranth. Blue LED460nm light irradiation improved the vital signs of the samples and extended the shelf life by 2–3 days. The AsA–GSH cycle was effectively activated with the irradiation of 30 μmol/(m2·s) blue LED460nm light. According to the results, the LED460nm light could retard the growth of colonies and the main spoilage bacteria, Pseudomonas aeruginosa, of freshly cut amaranth.

Comparison of the effects of LED light quality combination on growth and nutrient accumulation in green onion (Allium fistulosum L.).

The growth and development and metabolism of plants have different physiological responses to different light qualities. To study the influence of light qualities on green onions, the impacts of LED light treatment on the growth and development as well as the nutritional components and flavor substances in green onions were studied under controlled conditions. Leaf area, plant height, dry matter accumulation, Dickson's quality index (DQI), nutritional content, and volatile compounds under different light quality treatments were determined. The results indicated that the white and blue combined light (W/B: 3/1) treatment was the most beneficial to growth and nutrient accumulation and led to higher levels of sulfur compounds in the green onions than the other treatments. This shows that it is possible to control the contents of compounds that affect consumer preferences by adjusting the lighting conditions and to thereby increase the value and quality of seasoning vegetables.

Efek Penggunaan Beberapa Sinar LED pada Tanaman Buah Naga Merah (Hylocereus polyrhizus)

Effects of Using Multiple LED Beams on Red Dragon Fruit (Hylocereus polyrhizus). Red dragon fruit plant (H. polyrhizus) is a tropical plant and is very adaptable to growing environments and weather changes such as sunlight, wind, and rainfall. Dragon fruit plants is a long day plants (plants that require long enough sun exposure), which means that to produce this plant requires at least 12 hours of radiation. Knowing this, there needs to be a solution so that production stability can be controlled, one of which is by modifying the environment. The purpose of this study was to determine the effect of several colors of LED light (Light Emitting Diode) at the initiation stage of dragon fruit flowers in an effort to increase production. This study used a randomized block design with four treatments and nine replications, while the treatment consisted of control plants, the administration of white LED lights, yellow LED lights and blue LED lights. Three variables were observed, namely the number of flower buds, the number of blooming flowers and the number of young fruits. The results showed that the use of yellow LED lights give the best light intensity when compared to other treatments so that the yellow LED light treatment gave the best results on each variable including 6.44 pieces for flower buds, 7.56 pieces for flowers blooms and 7.56 pieces for young fruit.