Variation of phenotypic responses to lighting using a combination of red and blue light-emitting diodes versus darkness in seedlings of 18 vegetable genotypes

2019 ◽  
Vol 99 (2) ◽  
pp. 159-172
Author(s):  
Yun Kong ◽  
Youbin Zheng
Keyword(s):  
Phenotypic Plasticity ◽  
Light Emitting Diodes ◽  
Plant Traits ◽  
Germination Rate ◽  
Shoot Length ◽  
Fresh Mass ◽  
Plasticity Index ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Light Emitting

The objectives of this study were to identify traits and screen genotypes sensitive to narrow-waveband light-emitting diode light in 18 vegetable genotypes. Their phenotypic plasticity responses were examined under a combination of red (85%) and blue (15%) light-emitting diodes relative to darkness from seed germination to cotyledon unfolding. The photosynthetic photon flux density was around 316 μmol m−2 s−1 and the photoperiod was 17 h. Generally, light vs. dark delayed germination by reducing germination rate and increasing spread time of germination; inhibited shoot growth by reducing shoot length and fresh mass; promoted root growth by increasing root length, diameter, branching, and fresh mass; and promoted genotype-inherent colouring in leaves and stems. Shoot colour, shoot length, and (or) root branching showed higher plasticity indices than other plant traits in response to light, suggesting that some or all of these plant traits are more sensitive to lighting across the tested genotypes. Using cluster analysis based on the plasticity index, the 18 genotypes were separated into six groups that expressed response sensitivity to part or all of the above-mentioned traits. Based on the average plasticity index of all the tested plant traits, the 18 genotypes were graded into four groups using the Fisher optimal partition. Small- vs. large-seed species and the red- vs. green-leaf/root cultivars within the same species showed higher phenotypic plasticity indices in most cases, suggesting that they are more sensitive to lighting.

Automated measurement of leaf photosynthetic O 2 evolution as a function of photon flux density

1989 ◽  
Vol 323 (1216) ◽  
pp. 313-326 ◽  
Keyword(s):  
Flux Density ◽  
Light Emitting Diodes ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Automated Measurement ◽  
Light Emitting ◽  
Rate Of Photosynthesis ◽  
Polarographic Measurement

An automated procedure is described that allows the rate of photosynthesis, as a function of photon flux density (PFD), to be determined and plotted within 30 minutes. The method is based on polarographic measurement of O 2 evolution from a piece of leaf enclosed in a chamber and illuminated from above by an array of light-emitting diodes. The light emitted from these diodes is altered by a computer which also facilitates analyses of the data so derived. Applications of the procedure to leaves of shade and sun plants, to studies of photoinhibition and to analysis of the Kok effect, are described.

In vitro culture of Chrysanthemum plantlets using light-emitting diodes

2008 ◽  
Vol 3 (2) ◽  
pp. 161-167 ◽  
Author(s):  
Anželika Kurilčik ◽  
Renata Miklušytė-Čanova ◽  
Stasė Dapkūnienė ◽  
Silva Žilinskaitė ◽  
Genadij Kurilčik ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Spectral Component ◽  
Dry Weight ◽  
Chrysanthemum Morifolium ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Shoot Height ◽  
Light Emitting ◽  
Blue Component

AbstractEffects of illumination spectrum on the morphogenesis of chrysanthemum plantlets (Chrysanthemum morifolium Ramat. ‘Ellen’) grown in vitro were studied using an illumination system consisting of four groups of light-emitting diodes (LEDs) in the following spectral regions: blue (450nm), red (640nm), red (660nm), and far-red (735nm). Taking into account all differences in shoot height, root length, and fresh and dry weight (FW and DW, respectively), observed while changing the total photon flux density (PFD), the optimal total PFD for growth of chrysanthemum plantlets in vitro was estimated. For 16 h photoperiod and typical fractions of the spectral components (14%, 50%, 28%, and 8%, respectively), the optimal total PFD was found to be 40 µmol m−2 s−1. Our study shows that the blue component in the illumination spectrum inhibits the plantlet extension and formation of roots and simultaneously increases the DW to FW ratio and content of photosynthetic pigments. We demonstrate photomorphogenetic effects in the blue region and its interaction with the fractional PFD of the far-red spectral component. Under constant fractional PFD of the blue component, the root number, length of roots and stems, and fresh weight of the plantlets have a correlated nonmonotonous dependence on the fractional PFD of the far-red component.

scholarly journals Growing lettuce under multispectral light-emitting diodes lamps with adjustable light intensity

2017 ◽  
Vol 11 ◽  
Author(s):  
Giacomo Tosti ◽  
Paolo Benincasa ◽  
Rossano Cortona ◽  
Beatrice Falcinelli ◽  
Michela Farneselli ◽  
...  
Keyword(s):  
Light Intensity ◽  
Conversion Efficiency ◽  
Light Emitting Diodes ◽  
Biomass Conversion ◽  
High Energy ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Light Emitting ◽  
Light Spectra ◽  
Use Efficiency

Light-Emitting Diodes (LEDs) technology offers vast possibilities in plant lighting due to its ability to mix different light frequencies, high energy use efficiency and low heat production combined to long lifespan. In particular, the combined effect of the Blue:Red (B:R) ratio and other frequencies in the central part of the PAR spectrum (CGA, <em>i.e.</em> cyan, green and amber) may be very important, though literature information is scarce. In this paper, the effects of six light spectra from LED technology were tested, <em>i.e.</em>: (i) B:R=0.82 (<em>i.e.</em> similar to sunlight) with CGA (treatment T0), (ii) B:R=0.82 without CGA (T1), (iii) red prevalence (B:R=0.25) without CGA (T2), (iv) blue prevalence (B:R=4) without CGA (T3), (v) red prevalence with CGA (T4) and (vi) blue prevalence with CGA (T5). The experiment was carried out in a walk-in climatic chamber with controlled temperature and relative humidity and an incident PAR photon flux density (PFD) of 300 μmol m<sup>–2</sup> s<sup>–1</sup> (14/10 light/dark photoperiod), generated by multispectral LED lamps with adjustable light intensity. Smooth leaved lettuce (Lactuca sativa L. cv Gentilina) was used as the test plant and biomass yield (DW, g m<sup>–2</sup>), LAI, soil coverage proportion (SC%), energy-biomass conversion efficiency (E-BCE, kWh g<sup>–1</sup>) and Radiation Use Efficiency (RUE, g mol<sup>–1</sup> photons) were determined. Treatments with red predominance (T2 and T4) showed the highest SC% rates, while those with blue predominance (T3 and T5) showed the lowest. Light spectrum also affected leaf size (<em>i.e. </em>mean leaf area). The highest DW and RUE were observed in T2 and T4, followed by T0, while biomass in T3 and T5 was significantly lower (similar to T1). LAI values were generally high, but treatments with blue predominance showed the lowest LAI values (both with or without CGA). The introduction of intermediate wavelengths (green, cyan and amber) did not bring about significant improvement in DW or RUE, but resulted in reduced energy-biomass conversion efficiency, mainly due to lower architectural efficiency of the CGA LEDs. Future research should clarify how to optimise the light spectra according to the crop growth phases. The adoption of spectra promoting fast growth is fundamental in the early growth, while the use of spectra maximising yield quality may be more important later on.

The growth and morphology of microgreens is associated with modified ascorbate and anthocyanin profiles in response to the intensity of sole-source light-emitting diodes

2020 ◽  
Author(s):  
Chase Jones-Baumgardt ◽  
Qinglu Ying ◽  
Youbin Zheng ◽  
Gale G. Bozzo
Keyword(s):  
Light Emitting Diodes ◽  
Photosynthetic Pigment ◽  
Sole Source ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Total Phenolic ◽  
Hypocotyl Length ◽  
Total Anthocyanin ◽  
Light Emitting ◽  
Phytochemical Profiles

Sole-source light-emitting diodes (LEDs) are alternatives to fluorescent tubes and high intensity discharge lamps that are routinely used for indoor cultivation of horticultural commodities, including microgreens. This study examined the effect of photosynthetic photon flux density (PPFD) from LEDs on phytochemical profiles in organically grown kale, cabbage, arugula, and mustard microgreens, and their association with growth and morphological attributes. LEDs were used to deliver a 15% blue light and 85% red light mixture to microgreens at varying PPFDs between 100 and 600 μmol m-2 s-1. For all microgreens, increased concentrations of ascorbate (total and reduced) and total anthocyanin were proportional to PPFD. Total phenolic concentrations were elevated in all four microgreens at high PPFDs, whereas chlorophyll concentrations declined in arugula cabbage and mustard. A principal component analysis revealed anthocyanins and phenolics were associated with ascorbate levels in all microgreens, but not with chlorophylls or carotenoids. At high PPFDs photosynthetic pigment levels were negatively associated with fresh and dry weight to varying degrees. Anthocyanins, phenolics and ascorbate were negatively correlated with hypocotyl length and the colour attribute hue angle in all microgreens. These results indicate that microgreen growth and morphology are associated with altered phytochemical profiles during cultivation under sole source LEDs.

scholarly journals Seedling Growth Is Similar under Supplemental Greenhouse Lighting from High-pressure Sodium Lamps or Light-emitting Diodes

HortScience ◽  
2017 ◽  
Vol 52 (3) ◽  
pp. 388-394 ◽  
Author(s):  
Brian R. Poel ◽  
Erik S. Runkle
Keyword(s):  
High Pressure ◽  
Petunia Hybrida ◽  
Light Emitting Diodes ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Common Environment ◽  
Light Emitting ◽  
White Leds ◽  
Subsequent Flowering

Light-emitting diodes (LEDs) have the potential to replace high-pressure sodium (HPS) lamps as the main delivery method of supplemental lighting (SL) in greenhouses. However, few studies have compared growth under the different lamp types. We grew seedlings of geranium (Pelargonium ×hortorum), pepper (Capsicum annuum), petunia (Petunia ×hybrida), snapdragon (Antirrhinum majus), and tomato (Solanum lycopersicum) at 20 °C under six lighting treatments: five that delivered a photosynthetic photon flux density (PPFD) of 90 μmol·m−2·s−1 from HPS lamps (HPS90) or LEDs [four treatments composed of blue (B, 400–500 nm), red (R, 600–700 nm), or white LEDs] and one that delivered 10 μmol·m−2·s−1 from HPS lamps (HPS10), which served as a control with matching photoperiod. Lamps operated for 16 h·d−1 for 14 to 40 days, depending on cultivar and season. The LED treatments defined by their percentages of B, green (G, 500–600 nm), and R light were B10R90, B20R80, B10G5R85, and B15G5R80, whereas the HPS treatments emitted B6G61R33. Seedlings of each cultivar grown under the 90 μmol·m−2·s−1 SL treatments had similar dry shoot weights and all except pepper had a similar plant height, leaf area, and leaf number. After transplant to a common environment, geranium ‘Ringo Deep Scarlet’ and petunia ‘Single Dreams White’ grown under HPS90 flowered 3 days earlier than those grown under HPS10, but flowering time was not different from that in LED treatments. There were no consistent differences in morphology or subsequent flowering among seedlings grown under HPS90 and LED SL treatments. The inclusion of white light in the LED treatments played an insignificant role in growth and development when applied as SL with the background ambient light. The LED fixtures in this study consumed substantially less electricity than the HPS lamps while providing the same PPFD, and seedlings produced were of similar quality, making LEDs a suitable technology option for greenhouse SL delivery.

scholarly journals Different LED Light Wavelengths and Photosynthetic Photon Flux Density Effect on Colletotrichum acutatum Growth

Plants ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 143
Author(s):  
Neringa Rasiukevičiūtė ◽  
Aušra Brazaitytė ◽  
Viktorija Vaštakaitė-Kairienė ◽  
Alma Valiuškaitė
Keyword(s):  
Flux Density ◽  
Photosynthetic Photon Flux Density ◽  
Growth Characteristics ◽  
Colletotrichum Acutatum ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Photon Flux ◽  
Light Emitting ◽  
Led Light ◽  
Fungus Growth

The study aimed to evaluate the effect of different photon flux density (PFD) and light-emitting diodes (LED) wavelengths on strawberry Colletotrichum acutatum growth characteristics. The C. acutatum growth characteristics under the blue 450 nm (B), green 530 nm (G), red 660 nm (R), far-red 735 nm (FR), and white 5700 K (W) LEDs at PFD 50, 100 and 200 μmol m−2 s−1 were evaluated. The effect on C. acutatum mycelial growth evaluated by daily measuring until five days after inoculation (DAI). The presence of conidia and size (width and length) evaluated after 5 DAI. The results showed that the highest inhibition of fungus growth was achieved after 1 DAI under B and G at 50 μmol m−2 s−1 PFD. Additionally, after 1–4 DAI under B at 200 μmol m−2 s−1 PFD. The lowest conidia width was under FR at 50 μmol m−2 s−1 PFD and length under FR at 100 μmol m−2 s−1 PFD. Various LED light wavelengths influenced differences in C. acutatum colonies color. In conclusion, different photosynthetic photon flux densities and wavelengths influence C. acutatum growth characteristics. The changes in C. acutatum morphological and phenotypical characteristics could be related to its ability to spread and infect plant tissues. This study’s findings could potentially help to manage C. acutatum by LEDs in controlled environment conditions.

scholarly journals Critical Photoperiod and Optimal Quality of Night Interruption Light for Runner Induction in June-Bearing Strawberries

Agronomy ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1996
Author(s):  
Yali Li ◽  
Jie Xiao ◽  
Jiangtao Hu ◽  
Byoung Ryong Jeong
Keyword(s):  
Red Light ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Light Emitting ◽  
Red Led ◽  
Critical Photoperiod ◽  
Closed Walk ◽  
White Light Emitting Diodes ◽  
Optimal Quality

The optimal photoperiod and light quality for runner induction in strawberries ‘Sulhyang’ and ‘Maehyang’ were investigated. Two experiments were carried out in a semi-closed walk-in growth chamber with 25/15 °C day/night temperatures and a light intensity of 250 μmol·m–2·s–1photosynthetic photon flux density (PPFD) provided from white light-emitting diodes (LEDs). In the first experiment, plants were treated with a photoperiod of either 12, 14, 16, 18, 20, or 22 h In the second experiment, a total of 4 h of night interruption (NI) light at an intensity of 70 μmol·m–2·s–1PPFD provided from either red, blue, green, white, or far-red LED in addition to 11 h short day (SD). The results showed that both ‘Sulhyang’ and ‘Maehyang’ produced runners when a photoperiod was longer than 16 h, and the number of runners induced positively correlated with the length of photoperiod. However, the plant growth, contents of chlorophyll, sugar and starch, and Fv/Fo decreased in a 22 h photoperiod. All qualities of the NI light, especially red light, significantly increased the number of runners and daughter plants induced per plant as compared with those in the SD treatment in both cultivars. In a conclusion, a photoperiod between 16 and 20 h and NI light, especially red NI light, can be used for quality runner induction in both ‘Sulhyang’ and ‘Maehyang’.

scholarly journals Carbon gain optimization in five broadleaf deciduous trees in response to light variation within the crown: correlations among morphological, anatomical and physiological leaf traits

2015 ◽  
Vol 74 (1) ◽  
pp. 71-94 ◽  
Author(s):  
Rosangela Catoni ◽  
Loretta Gratani ◽  
Francesco Sartori ◽  
Laura Varone ◽  
Mirko U. Granata
Keyword(s):  
Phenotypic Plasticity ◽  
Deciduous Forest ◽  
Light Variation ◽  
Stress Factors ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Carbon Gain ◽  
Deciduous Species ◽  
Shade Leaves ◽  
Sun Leaves

AbstractLeaf trait variations in five deciduous species (Quercus robur, Corylus avellana, Populus alba, Acer campestre, Robinia pseudoacacia) growing in an old broadleaf deciduous forest in response to light variation within the tree crown was analyzed. Net photosynthetic rate (PN), leaf respiration rate (R) and the photosynthetic nitrogen use efficiency were, on average, more than 100% higher in sun than in shade leaves. A. campestre and C. avellana sun leaves had the highest specific leaf area (SLA, 156.0 ± 17.9 cm2 g-1) and the lowest total leaf thickness (L, 101.9 ± 8.8 μm) underlining their shade-tolerance. Among the shade-intolerant species (Q. robur, P. alba and R. pseudoacacia), Q. robur had the lowest SLA and the highest L in sun leaves (130.6 ± 10.0 cm2 g-1 and 160.8 ± 9.6 μm, respectively) since shade-intolerant species typically have thicker leaves. The higher PN decrease in respect to R decrease from sun to shade leaves attested the higher sensitivity of PN than R to light variations within the crown. This determined a 69% lower R/PN in sun than in shade leaves. This result is further attested by the significant correlation between PN and the relative photosynthetic photon flux density. The shade-tolerant species have a 76% higher R/PN ratio than the shade-intolerant ones. The measured leaf phenotypic plasticity (PI = 0.35) was in the range of broadleaf deciduous species. Plasticity is a key trait useful to quantify plant response to environmental stimuli. It is defined as the ability of a genotype to produce different phenotypes depending on the environment. Among the considered species, Q. robur showed the highest PI (0.39) and P. alba the lowest (0.29). Knowledge on phenotypic plasticity is important in making hypotheses about the dynamics of the studied forest in consideration of environmental stress factors, including invasive species competition and global climate change.

scholarly journals Optimal LED Wavelength Composition for the Production of High-Quality Watermelon and Interspecific Squash Seedlings Used for Grafting

Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 870 ◽  
Author(s):  
Filippos Bantis ◽  
Athanasios Koukounaras ◽  
Anastasios S. Siomos ◽  
Kalliopi Radoglou ◽  
Christodoulos Dangitsis
Keyword(s):  
Blue Emission ◽  
Dry Weight ◽  
Photosynthetic Photon Flux Density ◽  
Stem Diameter ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Light Sources ◽  
High Quality ◽  
Light Emitting ◽  
Shoot Dry Weight

Watermelon is cultivated worldwide and is mainly grafted onto interspecific squash rootstocks. Light-emitting diodes (LEDs) can be implemented as light sources during indoor production of both species and their spectral quality is of great importance. The objective of the present study was to determine the optimal emission of LEDs with wide wavelength for the production of watermelon and interspecific squash seedlings in a growth chamber. Conditions were set at 22/20 °C temperature (day/night), 16 h photoperiod, and 85 ± 5 μmol m−2 s−1 photosynthetic photon flux density. Illumination was provided by fluorescent (FL, T0) lamps or four LEDs (T1, T2, T3, and T4) emitting varying wide spectra. Watermelon seedlings had greater shoot length, stem diameter, cotyledon area, shoot dry weight-to-length (DW/L) ratio, and Dickson’s quality index (DQI) under T1 and T3, while leaf area and shoot dry weight (DW) had higher values under T1. Interspecific squash seedlings had greater stem diameter, and shoot and root DW under T1 and T3, while leaf and cotyledon areas were favored under T1. In both species, T0 showed inferior development. It could be concluded that a light source with high red emission, relatively low blue emission, and a red:far-red ratio of about 3 units seems ideal for the production of high-quality watermelon (scion) and interspecific squash (rootstock) seedlings.

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