scholarly journals Blue light promotes vascular reconnection, while red light boosts the physiological response and quality of grafted watermelon seedlings

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Filippos Bantis ◽  
Emmanuel Panteris ◽  
Christodoulos Dangitsis ◽  
Esther Carrera ◽  
Athanasios Koukounaras
Keyword(s):  
Blue Light ◽  
System Development ◽  
Citrullus Lanatus ◽  
Vascular Development ◽  
Red Light ◽  
Photosynthetic Apparatus ◽  
Light Emitting ◽  
Light Spectra ◽  
Root System Development

AbstractThe wound inflicted during grafting of watermelon seedlings requires rapid and sufficient vascular development which is affected by light quality. Our objective was to investigate the effect of light spectra emitted by light-emitting diodes (LEDs) during healing of grafted watermelon (Citrullus lanatus) seedlings on their vascular development, physiological and phytohormonal profile, and root architecture. Three LEDs emitting red (R), blue (B), and RB with 12% blue (12B) were tested in a healing chamber. During the first three days, the photosynthetic apparatus portrayed by PIABS, φP0, ψE0, and ΔVIP was less damaged and faster repaired in B-treated seedlings. B and 12B promoted vascular reconnection and root development (length, surface area and volume). This was the result of signaling cascade between phytohormones such as indole-3-acetic acid and others. After vascular reconnection the seedlings switched lights for 3 more days and the picture was reversed. Seedlings treated with B for the first 3 days and R for days 4 to 6 had better photosynthetic characteristics, root system development, morphological, shoot and root biomass, and quality (i.e. Dickson’s quality index) characteristics. We concluded that blue light is important during the first 3 days of healing, while the presence of red is necessary after vascular reconnection.

scholarly journals Manipulation of light spectrum can improve the performance of photosynthetic apparatus of strawberry plants growing under salt and alkalinity stress

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0261585
Author(s):  
Majid Esmaeilizadeh ◽  
Mohammad Reza Malekzadeh Shamsabad ◽  
Hamid Reza Roosta ◽  
Piotr Dąbrowski ◽  
Marcin Rapacz ◽  
...  
Keyword(s):  
Blue Light ◽  
Red Light ◽  
Photosynthetic Apparatus ◽  
Stress Conditions ◽  
Control Treatment ◽  
Light Spectrum ◽  
Light Spectra ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency ◽  
Metabolic Activities

Strawberry is one of the plants sensitive to salt and alkalinity stress. Light quality affects plant growth and metabolic activities. However, there is no clear answer in the literature on how light can improve the performance of the photosynthetic apparatus of this species under salt and alkalinity stress. The aim of this work was to investigate the effects of different spectra of supplemental light on strawberry (cv. Camarosa) under salt and alkalinity stress conditions. Light spectra of blue (with peak 460 nm), red (with peak 660 nm), blue/red (1:3), white/yellow (1:1) (400–700 nm) and ambient light were used as control. There were three stress treatments: control (no stress), alkalinity (40 mM NaHCO3), and salinity (80 mM NaCl). Under stress conditions, red and red/blue light had a positive effect on CO2 assimilation. In addition, blue/red light increased intrinsic water use efficiency (WUEi) under both stress conditions. Salinity and alkalinity stress decreased OJIP curves compared to the control treatment. Blue light caused an increase in its in plants under salinity stress, and red and blue/red light caused an increase in its in plants under alkalinity. Both salt and alkalinity stress caused a significant reduction in photosystem II (PSII) performance indices and quantum yield parameters. Adjustment of light spectra, especially red light, increased these parameters. It can be concluded that the adverse effects of salt and alkalinity stress on photosynthesis can be partially alleviated by changing the light spectra.

Plant Perception of Light: The role of indoleamines in Scutellaria species

2020 ◽  
Vol 3 (2) ◽  
pp. 161-176
Author(s):  
Jillian A Forsyth ◽  
Lauren A Erland ◽  
Paul R Shipley ◽  
Susan J Murch
Keyword(s):  
Plant Growth ◽  
Blue Light ◽  
White Light ◽  
Light Emitting Diode ◽  
Red Light ◽  
Plant Signaling ◽  
Full Spectrum ◽  
Light Emitting ◽  
Light Spectra ◽  
Lighting Systems

Light mediates plant growth through diverse mechanisms and signaling networks including plant growth regulators (PGRs). We hypothesized that a novel class of PGRs, the indoleamines, are plant signaling molecules that perceive changes in light composition and initiate a cascade of metabolic responses. We used three Scutellaria model species (skullcap): S. lateriflora, S. galericulata and S. racemosa that produce high levels of melatonin and serotonin to investigate this hypothesis. Axenic Scutellaria cultures were exposed to red, blue, green or full spectrum white light spectra provided by light emitting diode (LED) lighting systems, or daylight fluorescent bulbs. Melatonin (MEL), serotonin (5HT), abscisic acid (ABA), auxin (IAA), and jasmonic acid (JA), were quantified by liquid chromatography with tandem mass spectrometry. Melatonin was detected consistently in plants grown under blue light in all species of Scutellaria. In S. galericulata, significant quantities of ABA were detected in plants grown under white light but not detected in plants grown under other light spectra.  In timeline studies of S. racemosa plants exposed to limited red or blue light spectra had significantly reduced levels of tryptamine (TRM), 5HT and MEL in the shoots initially but melatonin was detected after 12 hours and quantifiable amounts of 5HT were detected after 7 days. Supplementation of the culture medium with MEL or 5HT did not change the pattern of MEL in blue light grown cultures but did change patterns of 5HT accumulation.  5HT was highest in plants grown under red light immediately after culture and decreased over 7 days.  These data indicate that the relative amounts of MEL and 5HT are responsive to light spectra and redirect metabolic resources to enable plant adaptations to changing environments.   

scholarly journals Effects of light spectra from light-emitting diodes on the growth and quality of grafted watermelon seedlings

2020 ◽  
Author(s):  
Φίλιππος Μπαντής
Keyword(s):  
Light Emitting Diodes ◽  
Citrullus Lanatus ◽  
Cucurbita Maxima ◽  
Light Emitting ◽  
Light Spectra

Το καρπούζι (Citrullus lanatus) είναι οικονομικά σημαντικό προϊόν το οποίο πολλαπλασιάζεται κυρίως μέσω εμβολιασμού. Η παραγωγή εμβολιασμένων σποροφύτων καρπουζιού αποτελείται από τρία διακριτά στάδια: την παραγωγή σποροφύτων προς εμβολιασμό (εμβόλιο και υποκείμενο) (στάδιο Ι), τον εμβολιασμό και την επούλωση των τομών εμβολιασμού (στάδιο ΙΙ), και τη σκληραγώγηση των εμβολιασμένων σποροφύτων (στάδιο ΙΙΙ). Ο κύριος στόχος της διατριβής ήταν η διερεύνηση της επίδρασης τεχνητού φωτισμού από διόδους εκπομπής φωτεινής ακτινοβολίας (light-emitting diodes, LEDs) ως συμπληρωματικός ή αποκλειστικός φωτισμός στην ποιότητα εμβολίων και υποκειμένων προς εμβολιασμό, καθώς και εμβολιασμένων σποροφύτων καρπουζιού. Επιπλέον, μελετήθηκε η επίδραση του φάσματος ακτινοβολίας λαμπτήρων LED στα τρία στάδια παραγωγής εμβολιασμένων σποροφύτων σε θάλαμο ανάπτυξης και σε θερμοκήπιο. Μελετώμενα είδη αποτέλεσαν το καρπούζι (εμβόλιο Celine F1) και το διειδικό υβρίδιο κολοκυθιού (υποκείμενο Cucurbita maxima × C. moschata “TZ-148). Αρχικά, καθορίσαμε κατηγορίες ποιότητας σποροφύτων στα τρία στάδια παραγωγής. Αναφέρουμε ότι το ξηρό βάρος υπέργειου τμήματος και ριζικού συστήματος, η διάμετρος ριζικού κόμβου και η φυλλική επιφάνεια είναι οι σημαντικότεροι δείκτες ποιότητας σποροφύτων στα τρία στάδια παραγωγής. Συνδυασμός «high» εμβολίων με «optimum» υποκειμένων είναι ιδανικός για την παραγωγή εμβολιασμένων σποροφύτων υψηλής ποιότητας. Επιπλέον, διερευνήθηκε η ανάγκη χρήσης τεχνητού φωτισμού στα τρία στάδια παραγωγής και καταλήξαμε ότι είναι απαραίτητος ο συμπληρωματικός φωτισμός στο θερμοκήπιο παραγωγής εμβολίων καθώς και σκληραγώγησης εμβολιασμένων σποροφύτων, ενώ οι λαμπτήρες φθορισμού δεν έχουν υψηλή απόδοση κατά το στάδιο επούλωσης. Κατόπιν, μελετήσαμε την επίδραση λαμπτήρων LED με ευρύ φάσμα ακτινοβολίας στην παραγωγή εμβολίων και υποκειμένων σε θάλαμο ανάπτυξης και βρήκαμε ότι LEDs με σχετικά υψηλό ποσοστό ερυθρού φωτός (53-64%) και χαμηλό ποσοστό κυανού φωτός (8-14%) οδήγησε σε ενισχυμένη ποιότητα. Στην περίπτωση του θερμοκηπίου, εμβόλια καρπουζιού παρουσίασαν βελτιωμένα ποιοτικά χαρακτηριστικά κάτω από συμπληρωματικό φωτισμό με LEDs συγκριτικά με λαμπτήρες υψηλής πίεσης νατρίου (HPS) λόγω ευνοϊκότερου φάσματος ακτινοβολίας. Η επούλωση αποτελεί ευαίσθητη διαδικασία κατά την οποία λαμβάνουν χώρα φυσιολογικές και ιστολογικές μεταβολές στα δύο τμήματα. Επομένως, μελετήσαμε την επίδραση φωτισμού με LEDs που εκπέμπουν ακτινοβολία μονοχρωματική ερυθρή (R), κυανή (Β) και συνδυασμούς ερυθρής-κυανής κατά τη διάρκεια της επούλωσης. Από τα αποτελέσματα προέκυψε ότι η R καθώς και ερυθρή με 12 ή 24% επιπρόσθετη κυανή ακτινοβολία (12Β ή 24Β) είχε θετική επίδραση σε σημαντικές μορφολογικές παραμέτρους, ενώ η Β ενίσχυσε παραμέτρους ανταλλαγής αερίων. Τα αποτελέσματα επιβεβαιώθηκαν από τη διερεύνηση τεσσάρων συνδυασμών γενοτύπων όπου δεν εντοπίστηκε σημαντική επίδραση του γενοτύπου. Κατόπιν, μελετήσαμε μεταβολές στην ανατομία της τομής εμβολιασμού και της αρχιτεκτονικής ρίζας και βρήκαμε ότι η κυανή ακτινοβολία είναι ευνοϊκή για την ταχεία ένωση του αγγειακού συστήματος εμβολίου-υποκειμένου και τον σχηματισμού ριζικού συστήματος τρεις μέρες από τον εμβολιασμό. Τις επόμενες ημέρες συνεχίστηκε η ένωση του αγγειακού συστήματος και η παρουσία ερυθρής ακτινοβολίας βελτίωσε την ανάπτυξη του ριζικού συστήματος. Επιπλέον, εμβολιασμένα σπορόφυτα κατά την σκληραγώγηση στο θερμοκήπιο παρουσίασαν αυξημένη ποιότητα κάτω από συμπληρωματικό φωτισμό με LEDs συγκριτικά με λαμπτήρες υψηλής πίεσης νατρίου (HPS). Σε όλα τα πειράματα με λαμπτήρες LED αναδείξαμε την επίδραση του ερυθρού και κυανού φάσματος ακτινοβολίας στη μορφολογία και φυσιολογία σποροφύτων και αποδείξαμε ότι ακόμα και μικρές μεταβολές στο φάσμα ακτινοβολίας ασκεί σημαντική επίδραση στη συμπεριφορά των φυτών.

(K0.5Na0.5)NbO3:Eu3+/Bi3+: a novel, highly efficient, red light-emitting material with superior water resistance behavior

RSC Advances ◽  
2015 ◽  
Vol 5 (6) ◽  
pp. 4707-4715 ◽  
Author(s):  
Qiwei Zhang ◽  
Haiqin Sun ◽  
Tao Kuang ◽  
Ruiguang Xing ◽  
Xihong Hao
Keyword(s):  
Blue Light ◽  
White Light ◽  
High Performance ◽  
Water Resistance ◽  
Light Emitting Diodes ◽  
Red Light ◽  
Light Emitting ◽  
Highly Efficient ◽  
White Light Emitting Diodes

Materials emitting red light (∼611 nm) under excitation with blue light (440–470 nm) are highly desired for fabricating high-performance white light-emitting diodes (LEDs).

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’.

Changes in light spectra modify secondary compound concentrations and BVOC emissions of Norway spruce seedlings

2020 ◽  
Author(s):  
Minna Kivimäenpää ◽  
Virpi Virjamo ◽  
Rajendra Prasad Ghimire ◽  
Jarmo Holopainen ◽  
Riitta Julkunen-Tiitto ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Blue Light ◽  
White Light ◽  
Carbon Allocation ◽  
Light Emitting Diode ◽  
Abiotic Stress Tolerance ◽  
Photon Flux ◽  
Emission Rates ◽  
Light Emitting ◽  
Light Spectra

Our objective was to study how changes in the light spectra affects growth, carbohydrate, chlorophyll, carotenoid, terpene, alkaloid and phenolic concentrations, and BVOC (biogenic volatile organic compound) emissions of Norway spruce (Picea abies) seedlings. This study was conducted during the growth of the third needle generation in plant growth chambers. Two light spectra with the main difference in proportion of blue light (400-500 nm) and equal photon flux densities were provided by LED (light-emitting diode) lamps: 1) control (white light + 12 % blue light) and 2) increased blue light (+B) (white light + 45% blue light). The +B treatment increased needle concentrations of total flavonoids and acetophenones. The major changes in the phenolic profile were an accumulation of astragalin derivatives and the aglycone of picein. +B decreased concentrations of the main alkaloid compound, epidihydropinidine, and it’s precursor, 2-methyl-6-propyl-1,6-piperideine, emission rates of limonene, myrcene and total monoterpenes, and concentrations of a few terpenoid compounds, mainly in stems. Growth, needle carbohydrates and pigments were not affected. The results suggest that supplemental blue light shifts carbon allocation between secondary metabolism routes, from alkaloid and terpenoid synthesis to flavonoid and acetophenone synthesis. The changes may affect herbivory and abiotic stress tolerance of Norway spruce.

scholarly journals Effects of photoperiod and light spectra on growth and pigment composition of the green macroalga Codium tomentosum

2020 ◽  
Author(s):  
Rúben Marques ◽  
Sónia Cruz ◽  
Ricardo Calado ◽  
Ana Lillebø ◽  
Helena Abreu ◽  
...  
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Blue Light ◽  
Early Development ◽  
Red Light ◽  
Pigment Composition ◽  
Relative Growth ◽  
Light Spectra ◽  
Short Day ◽  
Long Day

Abstract Codium tomentosum is a marine green macroalga with multiple value-added applications that is being successfully used as an extractive species in sustainable integrated multi-trophic aquaculture systems. Nonetheless, growth conditions of this species at an early development phase still require optimization. The present study addresses, under controlled laboratory conditions, the effects of photoperiod (long vs. short-day) and light spectra (white, blue, and red light) on growth and pigment composition of C. tomentosum. Relative growth rate was approximately 2× higher under long-day photoperiod (average of 39.2 and 20.1% week−1 for long and short-day, respectively). Concentrations per dry weight of major pigments such as chlorophyll a (Chla) and siphonoxanthin (Siph) were significantly higher under long-day photoperiod. Relative growth rates were higher under red light, intermediate under white light, and lower under blue light. These last results were rather surprising, as Siph-Chla/Chlb light harvesting complexes of Codium have increased absorption in the blue-green region of the light spectra. Changes in carbon allocation patterns caused by the spectral composition of light and overgrowth of green microalgae in blue light cultures could explain the differences recorded for relative growth rate. Long-day photoperiod and light sources with preferential emission at the red region of the light spectra were identified as optimal for growth of C. tomentosum at early development stages. These lighting conditions can reduce the time required to reach the necessary biomass before transfer to grow-out systems. Overall, these findings can shorten production time, increase macroalgal productivity, and enhance aquaculture revenues.

scholarly journals Suppression of Cucumber Powdery Mildew by Supplemental UV-B Radiation in Greenhouses Can be Augmented or Reduced by Background Radiation Quality

Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1349-1357 ◽  
Author(s):  
A. Suthaparan ◽  
A. Stensvand ◽  
K. A. Solhaug ◽  
S. Torre ◽  
K. H. Telfer ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Blue Light ◽  
Background Radiation ◽  
Red Light ◽  
Ultraviolet B ◽  
Disease Suppression ◽  
Radiation Quality ◽  
Light Emitting ◽  
Cucumber Powdery Mildew ◽  
Yellow Orange

This study demonstrates that the spectral quality of radiation sources applied with ultraviolet-B (UV-B; background radiation) affects the suppression of cucumber powdery mildew (Podosphaera xanthii) by UV-B. Suppression provided by daily UV-B exposure of 1 W/m2 for 10 min was greatest in the presence of red light or by a complete lack of background light, and powdery mildew suppression was least in the presence of ultraviolet-A (UV-A) or blue radiation compared with plants exposed only to 16 h of daily natural light supplemented with high-pressure sodium lamps that supply broad-spectrum radiation with peaks in the yellow-orange region. Exposure of powdery mildew-inoculated plants to supplemental red light without UV-B, beginning at the end of the daylight period, also reduced disease severity; however, supplemental blue light applied in the same fashion had no effect. Daily application of UV-B at 1 W/m2 beginning on the day of inoculation significantly reduced the severity of powdery mildew to 15% compared with 100% severity on control plants. Maximum suppression of powdery mildew was observed following 15 min of exposure to UV-B (1.1% severity compared with 100% severity on control plants) but exposure time had to be limited to 5 to 10 min to reduce phytotoxicity. There was no additional disease suppression when plants were exposed to UV-B beginning 2 days prior to inoculation compared with plants exposed to UV-B beginning on the day of inoculation. UV-B inhibited germination, infection, colony expansion, and sporulation of P. xanthii. The results suggest that efficacy of UV-B treatments, alone or in combination with red light, against P. xanthii can be enhanced by exposure of inoculated plants to these wavelengths of radiation during the night, thereby circumventing the counteracting effects of blue light and UV-A radiation. The effect of UV-B on powdery mildew seemed to be directly upon the pathogen, rather than induced resistance of the host. Night exposure of plants to 5 to 10 min of UV-B at 1 W/m2 and inexpensive, spectral-specific, light-emitting diodes may provide additional tools to suppress powdery mildews of diverse greenhouse crops.

scholarly journals Seeing the Light: The Roles of Red- and Blue-Light Sensing in Plant Microbes

2018 ◽  
Vol 56 (1) ◽  
pp. 41-66 ◽  
Author(s):  
Gwyn A. Beattie ◽  
Bridget M. Hatfield ◽  
Haili Dong ◽  
Regina S. McGrane
Keyword(s):  
Blue Light ◽  
Molecular Mechanisms ◽  
Red Light ◽  
Light Availability ◽  
Photosynthetic Apparatus ◽  
Light Regulation ◽  
Environmental Signals ◽  
Light Sensing ◽  
Fungal Phytopathogens ◽  
Bacteria And Fungi

Plants collect, concentrate, and conduct light throughout their tissues, thus enhancing light availability to their resident microbes. This review explores the role of photosensing in the biology of plant-associated bacteria and fungi, including the molecular mechanisms of red-light sensing by phytochromes and blue-light sensing by LOV (light-oxygen-voltage) domain proteins in these microbes. Bacteriophytochromes function as major drivers of the bacterial transcriptome and mediate light-regulated suppression of virulence, motility, and conjugation in some phytopathogens and light-regulated induction of the photosynthetic apparatus in a stem-nodulating symbiont. Bacterial LOV proteins also influence light-mediated changes in both symbiotic and pathogenic phenotypes. Although red-light sensing by fungal phytopathogens is poorly understood, fungal LOV proteins contribute to blue-light regulation of traits, including asexual development and virulence. Collectively, these studies highlight that plant microbes have evolved to exploit light cues and that light sensing is often coupled with sensing other environmental signals.

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