Effects Of Supplemental Lighting Research Articles

Effect of Supplemental Light for Leaves Development and Seed Oil Content in Brassica napus

Effect of Supplemental Light for Leaves Development and Seed Oil Content in Brassica napus

Effects of Supplemental Lighting on Flavonoid and Anthocyanin Biosynthesis in Strawberry Flesh Revealed via Metabolome and Transcriptome Co-Analysis.

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.

The Effect of Supplemental Lighting during the Late Gestation Period on Post-Partum Mechanical Properties of Mare and Foal Guard Hair.

This study investigates Thoroughbred mares exposed or not to supplemental blue light at the end of the gestation. Sixty mares and their 60 foals were selected for the investigation. Guard hair samples were collected from the shoulder just after (within 12 h) the parturition or birth. The foals of the light-treated mares developed significantly (p < 0.05) shorter hair than those of the control mares. A general effect of light treatment on basal hair diameter thinning could be demonstrated (p < 0.005). The maximum force of hair samples of light-treated mares and foals (0.098 and 0.085 N, respectively) was significantly lower than that of the control (0.272 and 0.178 N, respectively). The tensile strength (82.2 N/mm2) of the foal hair samples of the light-treated mares was significantly lower than that of the control foals (121.6 N/mm2). Although no significant difference was found in the elongation (ΔL), the hair of the control animals (mares and foals together) was more elastic than that of the treated animals (335 vs. 262 μm). In conclusion, the supplemental blue light treatment of the pregnant mares has a decreasing effect on both mares and their foals on the mechanical properties of the hair, making it shorter, thinner, and weaker.

The role of supplemental lighting during late fall and winter on photosynthetic and non-photosynthetic pigments biosynthesis of cut rose flower (Rosa hybrida cv. ‘Dolce Vita’)

ABSTRACT Low levels of natural light within the late fall and winter periods are main restricting factors for greenhouse-cut rose flower production in northern countries. Here, the effects of supplemental lighting on photosynthetic and non-photosynthetic pigments and the morphological response of cut rose flower cv. ‘Dolce Vita’ were investigated. Four different supplemental lighting regimes, including 85, 170, 255, and 340 μmol·m−2·s−1 PPFD using a high-pressure sodium lamp for a six-hour day extension started at sunset were applied to rose plants during late fall and winter. With increasing light intensity to 255 μmol·m−2·s−1 PPFD, the content of chlorophyll a, total chlorophyll, carotenoid content, and the ratio of chlorophylls a/b as well as amount of anthocyanins greatly improved. The highest phenol content and total antioxidant capacity was observed in 170 μmol·m−2·s−1 PPFD. Moreover, extending of daylength by light intensity of 255 μmol·m−2·s−1 PPFD had a significant affirmative effect on traits of growth, including flower stem length (P < 0.01), leaf number (P < 0.05), renewal bud formation (P < 0.05), time of harvesting (P < 0.05), and vase life of cut flowers (P < 0.01). Considering physiological and morphological improvement, extending of daylength from 10-h to 16-h by supplemental light of 255 μmol·m−2·s−1 PPFD would be the best choice to cultivate cut rose flower cv. ‘Dolce Vita’.

Chromatic Effects of Supplemental Light on the Fruit Quality of Strawberries

Chromatic Effects of Supplemental Light on the Fruit Quality of Strawberries

Effect of supplemental light, benzyl adenine (BA) on the growth and flowering of two cultivar of Chrysanthemum plant (Dendranthema grandiflora Tzvelev)

This study was conducted during the period from 23rd September 2021 to 1st May 2022 in Horticulture stations / Akre / Iraqi Kurdistan region, amid to scheduled the flower production of Chrysanthemum (Dendrathema grandiflora Tzvelev), by use the supplemental light with (Natural day, 1.5-month, 3-month) treatment, and BA with 0, 200 and 400 mg.l-1 and two cultivars Avalon (pink) and Flirt (red). The best results include, use 3-month of supplemental light significantly increased the day to flower bud, days to anthesis to 143.36, 201.10 day respectively compared with 1.5 month which need 119.61 , 175.02 day and control which need 49.28, 78.31day for the two characteristics respectively this mean that 3-month delay the flower production by 122.79 day than control, Plant high, the flower grade and Plant growth index also increased significantly with increased the supplemental light to 1.5 and 3-month compared with control. spray Chrysanthemum with BA increased significantly the day to flower bud emergence, vase life and flower grade compared with control. the Flirt (red) cultivar significantly superior than Avalon (pink) in day flower bud emergence, day flowering anthesis, plant high and flower grade. Key Words: supplemental light, benzyl adenine, cultivars, chrysanthemum

Effect of Supplementary Light with Different Wavelengths on Anthocyanin Composition, Sugar Accumulation and Volatile Compound Profiles of Grapes.

Protected cultivation is currently one of the main cultivation modes for grape production, but the long-term use of plastic film will have a certain negative impact on the light environment in vineyards, which in turn causes poor colouring, low sugar content and a lack of aroma in some red grape varieties. Supplementing light can be an effective way to mitigate these problems. In this study, vines of three red table grape varieties ('Summer Black', 'Xinyu' and 'Queen Nina') cultivated in a plastic greenhouse were supplemented with red, blue, white and red-blue light from veraison to harvest. All four supplemental light treatments increased the content of anthocyanins, sugars and volatile compounds in three grape varieties compared to CK (no supplemental lighting). Red-blue light treatment was the most favourable for the accumulation of anthocyanins and sugars, and the grapes treated with blue light had the highest content of volatile compounds. The grapes treated with red-blue light all obtained the highest composite scores via principal component analysis. For most of the sensory properties, the highest scores were obtained by the red-blue light-treated grapes. The results of this study will be useful in improving the colouring, sugar, and aroma content of grapes under protected cultivation.

Effect of supplementary lighting on nutrient recovery of Ocimum basilicum and fishes in a polyculture aquaponic system

Effect of supplementary lighting on nutrient recovery of Ocimum basilicum and fishes in a polyculture aquaponic system

Effect of Supplemental Inter-Lighting on Paprika Cultivated in an Unheated Greenhouse in Summer Using Various Light-Emitting Diodes.

This study investigated the effects of supplemental inter-lighting on paprika (cv. Nagano RZ) in South Korea in summer using various LED light sources. The following LED inter-lighting treatments were used: QD-IL (blue + wide-red + far-red inter-lighting), CW-IL (cool-white inter-lighting), and B+R-IL (blue + red (1:2) inter-lighting). To investigate the effect of supplemental lighting on each canopy, top-lighting (CW-TL) was also used. Additionally, a control without supplemental lighting was included for comparison. Significant variations were observed in the plant growth indexes 42 days after treatment. The SPAD values and total chlorophyll content in the last period of cultivation were significantly higher than those of the control. In November, the marketable fruit yield was significantly higher than that of the control. QD-IL, CW-IL, and CW-TL resulted in significantly higher values of total soluble solids than the control, and CW-IL resulted in higher values of ascorbic acid content than the control. Regarding the economic analysis, CW-IL resulted in the highest net income rate (12.70%) compared with the control. Therefore, the light sources of CW-IL were assessed as suitable for supplemental lighting due to the highest total soluble solids, ascorbic acid content, and net income rate obtained.

Supplemental light and silicon improved strawberry fruit size and sugars concentration under both full and deficit irrigation

Light, water and nutrient are essential factors influencing fruit quality of strawberry plants grown in commercial greenhouse. The aim of this study was to investigate the effect of supplemental light on the fruit quality as well as the effect of incorporating deficit irrigation and silicate spray on the plant nitrogen assimilation and fruiting of strawberry plants. The experimental plants were subjected to two light conditions, supplemental lighting (LED) and natural lighting environment (N), combining with two irrigation regimes, full irrigation (FI) or deficit irrigation (DI) and two foliar spray treatments, silicate spray (Si) or water spray (W), resulting in 8 treatments in total, viz., FIWN, FISiN, FIWLED, FISiLED, DIWN, DISiN, DIWLED, DIWLED. The Light treatment significantly elevated fruit polyphenols by 15.5% in the early season, and elevated fruit total sugar, glucose and fructose concentrations by 10.0%, 10.9% and 10.2% in the late season, respectively. The DI increased fruit anthocyanins concentration by 25% in the early season, and increased fruit glutamate concentration by 12.3% in the late season. The Si increased fruit anthocyanins, polyphenols and citrate concentrations by 41.7%, 14.7% and 8.2% in the early season, respectively, and increased single fruit mass by 8.8% in the late season. Furthermore, the Si enhanced the leaf GOGAT activity and glutamate concentration by 56.3% and 25.8%, respectively. The FISiLED and DIWLED had comparable advantages in elevating the fruit glucose, fructose, polyphenols and ascorbate concentrations in both seasons. Therefore, the silicate spray combined with supplemental lighting was recommended for growers to produce high quality strawberry fruit, and the deficit irrigation could be incorporated for the purpose of water conservation. The influence of supplemental light on the nitrogen metabolizing cycle and the carbohydrates transportation when the plants subjected to silicate spray or drought stress deserve further study.

Evaluation of the effects of supplemental lighting and stem number on greenhouse sweet pepper growth and yield via ray-tracing simulation with 3D plant models

Evaluation of the effects of supplemental lighting and stem number on greenhouse sweet pepper growth and yield via ray-tracing simulation with 3D plant models

Intensity of Supplemental Greenhouse Lighting Affects Strawberry Plant Growth, Anthracnose Infection Response, and Colletotrichum Pathogen Development in Culture

The effect of supplemental lighting on strawberry growth and anthracnose disease response of three strawberry (Fragaria ×ananassa) cultivars was evaluated in two greenhouse trials, and the effect on strawberry anthracnose pathogens (Colletotrichum sp.) was evaluated in the laboratory. The objective of the greenhouse trials was to determine the effect of various intensities of the red and blue light emitting diode (LED) light treatment on strawberry plant vigor, injury, and disease development. In these trials, the duration of supplemental light treatments was split into two 4-hour periods: dawn and dusk. The intensity of the red and blue LED bulbs was set using an adjustable dial at 1 or 3 in trial 1 and at 1, 5, or 10 in trial 2. Illuminance and photosynthetic photon flux densities of the light treatments ranged from lows of 402 lx and 5 μmol⋅m–2⋅s–1 (blue LED 1) to highs of 575 lx and 25 μmol⋅m–2⋅s–1 (red LED 1 + blue LED 3) in trial 1, and from lows of 4213 lx and 81 μmol⋅m–2⋅s–1 (red LED 1) to highs of 7051 lx (red LED 5) and 194 μmol⋅m–2⋅s–1 (red LED 10) in trial 2. Lower light intensities in trial 1 resulted in no significant differences as a result of light treatments in relative chlorophyll content, plant vigor ratings, or disease severity ratings (DSRs). However, plant injury ratings were significantly greater in plants in the wide-spectrum fluorescent (WSF) plus ultraviolet B (UVB) light treatment compared with the other treatments. Under the higher light intensities in trial 2, there were more significant effects among light treatments. Relative chlorophyll content of plants in the WSF + UVB, WSF, and red LED 1 treatments was significantly greater than that of plants in the red LED 10 treatment; however, plants in the red LED 10 treatment had the greatest injury ratings. Detached leaves from plants in the red 5 LED and red 10 LED treatments inoculated with Colletotrichum gloeosporioides received the greatest DSRs, and leaves from plants in the red LED 1 and WSF treatments received the lowest DSRs. In the laboratory, five days of exposure to supplemental lights did not prevent the growth of isolates of three species of Colletotrichum pathogens even though the intensity of the LED lights was set at their highest intensity. However, growth of isolates exposed to the WSF + UVB light treatment was slowed.

Effect of supplemental light, pinching, and number of plants per pot on the growth and flowering of chrysanthemum plant (Dendranthema grandiflora Tzvelev)

This study was conducted in the plastic house - Nursery of the Duhok University - Duhok governorate-Kurdistan region-Iraq from the period 10th Apr. 2021 to 10th Jan. 2022. This study aimed to investigate the effect of supplemental light (light and without light), pinching (pinching and without pinching) and number of plants per pot (2, 3, and 4) plants/pot on the growth and flowering of chrysanthemum (Dendranthema grandiflora Tzvelev) plant. The results showed that supplemental light for one month delayed the flower bud emergence (223.08) days, and flower anthesis (241.58) days compared with the control (without supplemental light) that gave (198.83, 218.44) days for the two characteristics respectively. Further, supplemental light gave the best results for flower length, flower diameter, flower number, and vase life compared to (without supplemental light). Pinching delayed the flower bud emergence and decreased the plant high, growth index, flower diameter, and vase life of cut flower significantly while it significantly increased the flower diameter and vasa life. Increasing the number of plants per pot to 4 plants caused a significant increment in flower number (8.25) compared with 2 plants which gave 5.64 plants/pot. The triple interaction showed significant differences in all characteristics and number of days to flower bud emergence and flower anthesis were the highest mean for the supplemental light with or without the pinch and 2 plants/pot. Also, the best plant height (72.33) cm and growth index (26761) cm3 were recorded without supplemental light, without pinch with 2 plants/pot. However, the maximum vase life of 26.33 days was found from the interaction of supplemental light, pinch, and 2 plants/pot.

The effect of supplementary light on the photosynthetic apparatus of strawberry plants under salinity and alkalinity stress

Considering the destructive effect of stresses on the photosynthetic apparatus of plants and the important role of light in photosynthesis, we investigated the effect of complementary light on the photosynthetic apparatus under salinity and alkalinity stress conditions. Light-emitting diodes (LEDs) in monochromatic blue (460 nm), monochromatic red (660 nm), dichromatic blue/red (1:3), white/yellow (400–700 nm) at 200 μmol m−2 S−1, and without LED treatment were used. The stress treatments were in three stages: Control (no stress), Alkalinity (40 mM NaHCO3), and Salinity (80 mM NaCl). Our results showed that salinity and alkaline stress reduced CO2 assimilation by 62.64% and 40.81%, respectively, compared to the control treatment. The blue light spectrum had the highest increase in water use efficiency (54%) compared to the treatment without supplementary light. Under salinity and alkalinity stress, L, K, and H bands increased and G bands decreased compared to the control treatment, with blue/red light causing the highest increase in L and K bands under both stress conditions. In salinity and alkalinity stress, white/yellow and blue/red spectra caused the highest increase in H bands. Complementary light spectra increased the G band compared to the treatment without complementary light. There was a significant decrease in power indices and quantum power parameters due to salt and alkalinity stress. The use of light spectra, especially blue, red, and blue/red light, increased these parameters compared with treatment without complementary light. Different light spectra have different effects on the photosynthetic apparatus of plants. It can be concluded that using red, blue spectra and their combination can increase the resistance of plants to stress conditions and be adopted as a strategy in planting plants under stress conditions.

Effect of Light-emitting Diodes, Ultraviolet-B, and Fluorescent Supplemental Greenhouse Lights on Strawberry Plant Growth and Response to Infection by the Anthracnose Pathogen Colletotrichum gloeosporioides

Supplemental lighting is frequently used to extend daylength for strawberries (Fragaria ×ananassa) grown in greenhouses and high tunnels; however, information is limited on the effect of these lights on disease development. We evaluated the effect of ambient light and six supplemental light treatments [red, blue, and white light-emitting diodes (LEDs), separately; a combination of red, blue, and white LEDs; wide-spectrum fluorescent (WSF); and WFS + ultraviolet B (UV-B)] on plant growth and disease response of strawberries grown in a greenhouse. Plants were exposed to supplemental light treatments for 17 h each day. In the WSF+UV-B treatment, plants were exposed to WSF light during the day and to UV-B light for 3 hours during the night. Two trials were conducted; each trial contained five or six cultivars and was replicated three times. Twice during each trial, detached leaves from each cultivar in each light treatment were inoculated with a conidial suspension of the anthracnose crown rot pathogen, Colletotrichum gloeosporioides and rated for disease severity 10 days later. There was a significant difference due to light treatment and to cultivar in relative chlorophyll content and plant growth parameters. Plant injury ratings were lowest in the white LED, WSF, and WSF+UV-B treatments. Plants in the combination LED and red LED light treatments received higher injury, lower vigor scores, and lower relative chlorophyll content values than plants in all other light treatments. After inoculation of detached strawberry leaves with C. gloeosporioides in Trial 1, there was a significant effect due to light treatments on disease severity ratings (DSRs) after 18 weeks’ exposure to light treatments with the DSRs in the WSF+UV-B treatment being lower than those in all other treatments except those in the red LED treatment. There was not a significant effect in DSRs due to light treatments after 24 weeks in Trial 1 or after 4 or 22 weeks in Trial 2. There were significant effects due to cultivar on DSRs in both trials: ‘Strawberry Festival’, ‘Pelican’, and ‘Seascape’ received the lowest DSRs. This study showed an effect of supplemental light on several strawberry plant growth parameters, including a harmful effect of high-intensity red LED irradiation.

Factors Influencing the Efficacy of Biological Control Agents Used to Manage Insect Pests in Indoor Cannabis (Cannabis sativa) Cultivation

Current biological control strategies in cannabis (Cannabis sativa) cultivation have resulted in poor efficacy for managing certain insect pests. The cannabis industry has grown at a rapid pace, surpassing our ability to develop knowledge on the production systems for this crop. Currently, the research focus is on optimizing agronomic and environmental factors to maximize the yield and quality of cannabis. However, cannabis growers are increasingly challenged by severe insect pest pressure, with few effective options. Decades of research have optimized biological control strategies in other crops. The implementation of effective biological control strategies in cannabis is hindered by a variety of morphological, biochemical, and agronomic factors unique to this crop. Here, we review the rather limited literature relevant to insect pest management in indoor cannabis production. Further, we have identified three factors that we believe are primarily responsible for the ineffectiveness of biological control in cannabis: Plant morphology including trichome density and floral resources, effects of plant biochemistry on prey suitability, and finally the effects of supplemental lighting including photoperiod, intensity, and spectrum. We highlight the importance of prioritizing the evaluation of these factors to improve our understanding of the tritrophic interactions governing the success of biological control in cannabis cultivation. As intensive research efforts are underway to optimize agronomic practices for cannabis, it is also important to consider their relevance to biological control.

Effects of supplemental light on tomato growth and the mechanism of the photosystem II apparatus.

The addition of supplemental light (SL) is an effective way to offset insufficient lighting. Although it is commonly believed that SL increases leaf photosynthesis and therefore improves yield and fruit flavor, the mechanism underlying the effects of SL on the photosystem II (PSII) apparatus remains unclear, and SL leads to high energy consumption. In order to save energy, we investigated the physiological status of the PSII apparatus, plant growth parameters and fruit parameters under two types of overhead SL with a low daily energy consumption of 0.0918 kWh m-2. The results showed that SL significantly increased the leaf chlorophyll content from full unfolding to yellowing. However, a remarkable increase in the absorption flux per cross-section (ABS/CS), the quantum yield of electron transport (φEo) and the performance index (PIabs) was observed only in a relatively short period of the leaf life cycle. SL also enhanced the fruit yield and quality. The obviously increased ΔVK and ΔVJ components of the chlorophyll fluorescence induction kinetic (OJIP) curve, along with the significantly decreased PIabs from days 40–60 after unfolding in the SL-treated groups, resulted in more rapid leaf aging and earlier fruit ripening compared with the control plants (CK). Therefore, an energy-friendly SL strategy can alter the physiological status of the PSII apparatus, affecting yield and fruit quality and maturity.

Effects of Supplemental Lighting at Different Positions on Tomato Plant Morphology,Photosynthesis and Endogenous Hormone Biosynthesis Under Low-light Environment

Effects of Supplemental Lighting at Different Positions on Tomato Plant Morphology,Photosynthesis and Endogenous Hormone Biosynthesis Under Low-light Environment

LED Intercanopy Lighting in Blackberry During Spring Improves Yield as a Result of Increased Number of Fruiting Laterals and Has a Positive Carryover Effect on Autumn Yield.

High market price and low availability of local winter and spring production has stimulated production of blackberries in glasshouses at northern latitudes. For this production, light is the main limiting factor. We investigated the potential of intercanopy lighting (ICL) using light emitting diodes (LEDs) to improve blackberry fruit yield in a crop with a spring and an autumn production cycle. During the spring production cycle three light treatments were applied: only natural light (no ICL), 93 or 185 μmol m–2 s–1 ICL In summer the lateral shoots were cut back and 93 μmol m–2 s–1 ICL was applied to all plants after cutting back, investigating a possible carryover effect of supplemental light in spring on autumn production. Fresh fruit yield in spring increased by 79 and 122% with 93 and 185 μmol m–2 s–1 ICL, respectively, compared to no ICL. This represents 3.6 and 2.8% increase in harvestable product for every additional 1% of light. A yield component analysis and leaf photosynthesis measurements were conducted. Maximum photosynthetic capacity (Amax) for leaves at 185 μmol m–2 s–1 ICL was about 50% higher, and LAI was 41% higher compared to no ICL. ICL increased the number of fruiting laterals per cane, and this explained 75% of the increase in yield. ICL at 185 μmol m–2 s–1 resulted in a higher yield compared to no ICL, primarily as a result of higher total dry matter production. Furthermore, a higher fraction of dry matter partitioned to the fruits (0.59 compared to 0.52) contributed to yield increase, whereas fruit dry matter content and fruit quality (sugar and acid content) was not affected by ICL. Averaged over the three light treatments autumn yield was 47% lower than spring yield. Autumn yield was 10% higher for plants at ICL 93 μmol m–2 s–1 in spring and 36% higher for plants at 185 μmol m–2 s–1 in spring compared to no ICL in spring. This increased autumn yield was caused by more fruiting laterals (less necrotic buds). It is concluded that management practices in spring can have a carryover effect on the autumn production. This is the first scientific paper on the potential for applying LED ICL in blackberries. Further research should focus on optimal intensity of ICL, positioning of supplementary lighting and economic feasibility.

Upward LED Lighting from the Base Suppresses Senescence of Lower Leaves and Promotes Flowering in Indoor Rose Management

In indoor environments such as hotels, the light intensity is generally insufficient for managing plants, and flower buds often fail to open. Lamps placed above (downward lighting) take up space. We assessed the applicability of lighting from underneath (upward lighting) for the indoor management of roses. We grew plants indoors in dim light for 2 weeks under three conditions: 1) without supplemental lighting, 2) with downward light-emitting diode (LED) lighting, and 3) with LED lighting. We quantified photosynthetic components (chlorophyll and rubisco) and the maximum quantum yield of photosystem II (Fv/Fm, an indicator of plant health) to determine the effects of each treatment on the quality and photosynthetic abilities of the leaves. We determined the ratios of dead and opened flower buds to elucidate the effects of supplemental lighting on flower bud maturation. Management without supplemental lighting decreased the number of flowers and resulted in lower-leaf senescence. Downward LED lighting promoted blooming but also resulted in lower-leaf senescence. However, upward LED lighting promoted blooming and maintained the photosynthetic abilities of the leaves, including the lower leaves. This study shows a strong case for using upward LED lighting in appropriate settings for indoor plant management and LED-based horticulture.