Light Dark Research Articles

Maltese Coastline Never Sleeps: The Effects of Artificial Light at Night (ALAN) on the Local Infralittoral Assemblages—A Case Study

Aside from the most notorious threats, the Mediterranean Sea faces novel and poorly explored impacts from artificial light at night (ALAN), which influences natural light–dark cycles and affects marine ecosystems. This study investigates the impact of ALAN on coastal infralittoral assemblages in Malta, where such effects remain unexplored. Using Baited Remote Underwater Videos (BRUVs), we examined the influence of different light intensities on species assemblages and behaviour at two sites: a light-polluted harbour and a darker reef area. Our findings reveal significant differences in fish community composition between light treatments and habitats. Among the 23,955 individuals recorded across multiple taxa, Boops boops accounted for 80% of observations. From our results, light intensity had a more substantial impact on community structure than habitat type, with species-specific responses to light. Predatory species such as Trachurus trachurus displayed increased activity under high-intensity white light, while Apogon imberbis and Serranus scriba were more abundant under red light, irrespective of habitat. These results underscore the role of ALAN in altering marine community dynamics and emphasise the need for sustainable management strategies to mitigate its impact on the biodiversity of the Mediterranean. This study provides initial empirical evidence of ALAN’s effects in Maltese waters, contributing to broader efforts to understand and manage light pollution in marine ecosystems.

Linear response theory for light dark matter-electron scattering in materials

We combine the nonrelativistic effective theory of dark matter (DM)-electron interactions with linear response theory to obtain a formalism that fully accounts for screening and collective excitations in DM-induced electronic transition rate calculations for general DM-electron interactions. In the same way that the response of a dielectric material to an external electric field in electrodynamics is described by the dielectric function, so in our formalism the response of a detector material to a DM perturbation is described by a set of which can be directly related to densities and currents arising from the nonrelativistic expansion of the Dirac Hamiltonian. We apply our formalism to assess the sensitivity of non-spin-polarized detectors, and find that in-medium effects significantly affect the experimental sensitivity if DM couples to the detector's electron density, while being decoupled from other densities and currents. Our formalism can be straightforwardly extended to the case of spin-polarized materials. Published by the American Physical Society 2024

Minocycline reduces neurobehavioral deficits evoked by chronic unpredictable stress in adult zebrafish

Chronic stress-related brain disorders are widespread and debilitating, and often cause lasting neurobehavioral deficits. Minocycline, a common antibiotic and an established inhibitor of microglia, emerges as potential treatment of these disorders. The zebrafish (Danio rerio) is an important emerging model organism in translational neuroscience and stress research. Here, we evaluated the potential of minocycline to correct microglia-mediated behavioral, genomic and neuroimmune responses induced by chronic unpredictable stress (CUS) in adult zebrafish. We demonstrated that CUS evoked overt behavioral deficits in the novel tank, light–dark box and shoaling tests, paralleled by elevated stress hormones (CRH, ACTH and cortisol), and upregulated brain expression of the ‘neurotoxic M1′ microglia-specific biomarker gene (MHC-2) and pro-inflammatory cytokine genes (IL-1β, IL-6 and IFN-γ). CUS also elevated peripheral (whole-body) pro-inflammatory (IL-1β, IFN-γ) and lowered anti-inflammatory cytokines (IL-4 and IL-10), as well as reduced whole-brain serotonin, dopamine and norepinephrine levels, and increased brain dopamine and serotonin turnover. In contrast, minocycline attenuated most of these effects, also reducing CUS-elevated peripheral levels of IL-6 and IFN-γ. Collectively, this implicates microglia in zebrafish responses to chronic stress, and suggests glial pathways as potential evolutionarily conserved drug targets for treating stress-evoked neuropathogenesis. Our findings also support the growing translational value of zebrafish models for understanding complex molecular mechanisms of brain pathogenesis and its therapy.

Research on light dark matter particle from evaporating primordial black hole in CDEX-10 experiment

Research on light dark matter particle from evaporating primordial black hole in CDEX-10 experiment

Electroacupuncture negatively regulates the Nesfatin-1/ERK/CREB pathway to alleviate HPA axis hyperactivity and anxiety-like behaviors caused by surgical trauma

BackgroundHyperactivity of the hypothalamic–pituitary–adrenal (HPA) axis constitutes a pivotal response by surgical trauma, manifesting as a critical aspect of the acute stress reaction. This hyperactivity resulted in adverse surgical outcomes and is often associated with increased postoperative anxiety. Increased evidence suggests that Nesfatin-1 plays a crucial role in stress responses and stress-related psychiatric disorders. Electroacupuncture (EA) is widely used to alleviate stress responses and anxiety, although its mechanism of action remains unclear. This study aimed to assess the mechanisms by which hypothalamic Nesfatin-1 contribute to the alleviation of HPA axis hyperactivity and anxiety by EA.MethodsPartial hepatectomy (HT) was performed to simulate surgical trauma, and EA was applied at Zusanli (ST36) and Sanyinjiao (SP6). The levels of hypothalamic Nesfatin-1, c-Fos, and corticotropin-releasing hormone (CRH) were detected, and serum adrenocorticotropic hormone (ACTH) and corticosterone (CORT) were regarded as indicators of HPA axis activity. Anxiety levels were assessed through open field tests (OFT), elevated plus maze (EPM), and light–dark box tests (LDBT). To investigate the role of Nesfatin-1, its expression was modulated using stereotactic viral injections or plasmid transfections. Transcriptome sequencing was employed to explore the downstream signaling pathways of Nesfatin-1. Additionally, brain cannula implantation was performed to facilitate targeted drug administration.ResultsOur findings demonstrated that EA reduced the hypothalamic overexpression of CRH and Nesfatin-1, as well as serum levels of ACTH and CORT. Additionally, it alleviated anxiety-like behaviors resulting from surgical trauma. We observed that overexpression of Nesfatin-1 in the hypothalamic paraventricular nucleus (PVN) triggered hyperactivity of the HPA axis and anxiety. Conversely, knocking down Nesfatin-1 in the PVN reversed these effects caused by surgical trauma. Transcriptome sequencing identified the extracellular regulated protein kinases (ERK)/cAMP-response element binding protein (CREB) pathway as a key mediator in the impacts of surgical trauma and EA on the hypothalamus. Both in vivo and in vitro studies showed that overexpression of Nesfatin-1 activated the ERK/CREB pathway. Furthermore, administering ERK or CREB inhibitors into the PVN mitigated HPA axis hyperactivity and anxiety-like behaviors induced by surgical trauma. Finally, EA was observed to decrease the phosphorylation levels of ERK and CREB in the PVN.ConclusionEA alleviates HPA axis hyperactivity and anxiety-like behaviors caused by surgical trauma through inhibition of Nesfatin-1/ERK/CREB pathway in the hypothalamus.

Flavor phenomenology of light dark vectors

Light dark matter with flavor-violating couplings to fermions may be copiously produced in the laboratory as missing energy from decays of SM particles. Here we study the effective Lagrangian of a light dark vector with generic dipole or vector couplings. We calculate the resulting two-body decay rates of mesons, baryons and leptons as a function of the dark vector mass and show that existing experimental limits probe UV scales as large as 1012 GeV. We also derive the general RGEs in order to constrain the flavor-universal UV scenario, where all flavor violation arises radiatively proportional to the CKM matrix.

Blue lighting combined with cold storage temperature can suppress gray mold in strawberry fruit

Cold storage is an optimal way of preventing quality deterioration in fruit crops, and this is exemplified by strawberries. However, Botrytis cinerea, the causal agent of gray mold, is cold-adaptive and can cause losses to cold-stored fruit. This study evaluated the regulatory effects of the spectral quality of light on the fungal growth in vitro, and the development of gray mold on postharvest strawberries at both ambient (21 ℃) and cold (4 ℃) temperatures. None of the light qualities tested (white, blue, green, or red) significantly affected colony growth of B. cinerea compared with the dark conditions in which they were tested at 21 ℃. In fungal cultures kept at 4 ℃, blue light significantly retarded colony expansion compared to other light conditions and darkness. Moreover, blue light and cold conditions can synergistically result in an increased number of septa, hyphal abnormality and intracellular vacuoles. An enhanced accumulation of reactive oxygen species (ROS) was also observed in fungal hypha exposed to blue light under cold conditions. Infection assay on strawberries demonstrated that blue light caused insignificant and significant suppressive effects at 21 ℃ and 4 ℃, respectively. In addition, blue-light caused significant weight loss in strawberries compared with all other treatments. Consequently, blue-light illumination under cold conditions may result in oxidative stress to the B. cinerea cells, thus preventing this cold-adaptive pathogen from causing unexpected deterioration in the stored fruit.

Improving light availability and creating high-frequency light–dark cycles in raceway ponds through vortex-induced vibrations for microalgae cultivation: a fluid dynamic study

Limited light availability due to insufficient vertical mixing strongly reduces the applicability of raceway ponds (RWPs). To overcome this and create light–dark (L/D) cycles for enhanced biomass production through improved vertical mixing, vortex-induced vibration (VIV) system was implemented by the authors in a previous study to an existing pilot-scale RWP. In this study, experimental characterization of fluid dynamics for VIV-implemented RWP is carried out. Particle image velocimetry (PIV) technique is applied to visualize the flow. The extents of the vertical mixing due to VIV and the characteristics of L/D cycles were examined by tracking selected particles. Pond depth was hypothetically divided into three zones, namely dark, light Iimited and light saturated for detailed analysis of cell trajectories. It has been observed that VIV cylinder oscillation can efficiently facilitate the transfer of cells from light-limited to light-saturated zones. Among the cells that were tracked, 44% initially at dark zone entered the light-limited zone and 100% of initially at light-limited zone entered the light-saturated zone. 33% of all tracked cells experienced high-frequency L/D cycles with an average frequency of 35.69 s−1 and 0.49 light fraction. The impact of VIV was not discernible in the deeper sections of the pond, due to constrained oscillation amplitudes. Our findings suggest that the approximately 20% increase in biomass production reported in our previous study can be attributed to the synergistic effects of enhanced L/D cycle frequencies and improved light availability resulting from the transfer of cells from dark to light-limited zones. To further enhance the effectiveness of VIV, design improvements were developed. It was concluded that light availability could be significantly improved with the presented method for more effective use of RWPs.

Dark sink enhances the direct detection of freeze-in dark matter

We describe a simple dark sector structure which, if present, has implications for the direct detection of dark matter (DM); . A dark sink transports energy density from the DM into light dark-sector states that do not appreciably contribute to the DM density. As an example, we consider a light, neutral fermion ψ which interacts solely with DM χ via the exchange of a heavy scalar Φ. We illustrate the impact of a dark sink by adding one to a DM freeze-in model in which χ couples to a light dark photon γ′ which kinetically mixes with the Standard Model (SM) photon. This freeze-in model (absent the sink) is itself a benchmark for ongoing experiments. In some cases, the literature for this benchmark has contained errors; we correct the predictions and provide them as a public code. We then analyze how the dark sink modifies this benchmark, solving coupled Boltzmann equations for the dark-sector energy density and DM yield. We check the contribution of the dark sink ψ’s to dark radiation; consistency with existing data limits the maximum attainable cross section. For DM with a mass between MeV−O(10 GeV), adding the dark sink can increase predictions for the direct detection cross section all the way up to the current limits. Published by the American Physical Society 2024

Investigating the Effects of Dark Period Light Exposure on Sex Expression In Female Cannabis sativa

Hermaphroditism in female plants is a common problem in the cannabis industry. Cannabis sativa florogenesis is dependent on photoperiod, and industry experts suspect disruptions to the photoperiod contribute to hermaphroditism. The goals of this report are to (i) determine the relationship between hermaphroditism and dark period light exposure in C. sativa, (ii) identify a causal mechanism that could explain female hermaphroditism, and (iii) recommend a course of action for indoor cultivators. A literature search suggested that hermaphroditism in C. sativacould be the result of a very low fluence response. To test this idea, 403 plants grown indoors were inspected for male flowers. The distance of each plant from the nearest grow room door—the proposed source of dark period light—was used to calculate relative dark period light intensity values for each plant. Linear regression analysis was used to assess the relationship between relative light intensity and males per plant. The average males per plant was 0.136, compared with an intercept coefficient of 0.125 (p=0.00197, R2=0.0162). Based on these results, proximity to a door does not affect hermaphroditism. Because the actual light intensities during dark periods in this study were likely too low to cause very low fluence responses, this study cannot confidently evaluate the relationship between dark period light exposure and hermaphroditism in C. sativa. Management at the study site would be advised not to spend resources addressing grow room door light leaks.

Effect of Ambient Lighting on Intraocular Pressure Rhythms in Rats.

The purpose of this study was to determine the effects of ambient lighting on intraocular pressure (IOP) rhythmicity and variability. IOP was continuously recorded by wireless telemetry from rats under light/dark (LD), dark/light (DL), asymmetric (6L18D and 18D6L), constant dark (DD), and constant light (LL) cycles. In some DD experiments, 1-hour light pulses were presented at varying times. IOP rhythmicity and variability were respectively quantified via cosinor analysis and peak detection algorithms that identified transient and sustained fluctuations. Rat IOP peaked at night and troughed during the day with LD amplitude of 8.7 ± 3.4mm Hg. Rhythmicity persisted in DD and LL with a free-running period of 24.1 ± 0.3 and 25.2 ± 0.4 hours, respectively. Peak-to-trough amplitude was approximately 60% smaller in LL, often disappeared after 1 to 2 weeks as daytime IOP drifted 2.6 ± 1.5mm Hg higher, and returned to approximately 60% larger in LD. Rhythmicity was similarly impacted but resynchronized to DL over 4 to 6days. Rhythmicity was unaltered by short photoperiods (6L18D), but the nocturnal IOP elevation was markedly shortened by long photoperiods (18L6D) and temporarily lowered to daytime levels by light pulses during the subjective night. Transient and sustained event rate, amplitude, interval, and energy content were nearly identical in LD, DD, and LL. Aqueous humor dynamics of rat eyes are intrinsically configured to set IOP at daytime levels. Circadian clock input modulates these dynamics to elevate IOP at night. Light at night blocks this input, sending IOP back to daytime levels. Effects of abnormal lighting on IOP rhythmicity may contribute to pressure-related ocular neuropathies.

Extraction of melanin from the shell and mantle and activities of enzymes related to the melanin biosynthesis in the Ruditapes philippinarum

The shell surface of Manila clam (Ruditapes philippinarum) has a variety of colors and stripes, with diverse shell color polymorphism. As an important trait of economic shellfish, shell color plays an important role in the selection breeding of shellfish species. In this study, we extracted melanin from the shell and mantle of R. philippinarum by the hydrochloric acid method and measured the melanin content by spectrophotometry. The absorption spectrum of melanin and its absorption peak at 350 nm absorbance was determined. We found significant differences in the melanin content of clams with dark strain and light strain, as well as four different shell colors. Moreover, we further detected the activities of enzymes related to melanin synthesis in R. philippinarum mantle, such as tyrosinase (TYR), tyrosine hydroxylase (TH), dopa decarboxylase (DDC), N-acetyltransferase (NAT), and N-β- alanyldopamine (NBAD) in the mantle of R. philippinarum. The results showed that the activities of TYR, TH, DDC and NAT were positively correlated with the content of melanin. However, the activity of NBAD was negatively correlated with the content of melanin. Altogether, these results indicating that these enzymes are involved in the regulation of the melanogenesis pathway of R. philippinarum. This study provides valuable information for further research on shell color genetic mechanism and breeding of R. philippinarum.

Fe3O4/ZnO/L-lysine functionalized graphene oxide a promising nanocomposite with double Z-scheme visible photocatalytic and dark catalytic activity for water remediation

Developing multifunctional catalysts for efficient pollutant degradation in dark and visible light conditions represents a significant advancement in water remediation technology. This study reports the synthesis of a novel Fe3O4/ZnO/Lys-rGO nanocomposite via environmentally friendly methods that exhibit catalytic-photocatalytic activity for efficient degradation of organic pollutants. The synergistic effect of compositing Lys-rGO, a bio-organic component with a narrow band gap (1.08 eV), into the Fe3O4/ZnO inorganic composite induces a double Z-scheme mechanism by providing two pathways for effective charge separation in the visible photocatalytic activity of the nanocomposite. Additionally, the stored electrons in the very conductive Lys-rGO layers offer active sites for the catalytic activity of the nanocomposite in the dark. Meanwhile, ZnO generates reactive oxygen species (ROS) through surface oxygen vacancies, further contributing to the nanocomposite’s dark catalytic activity. The degradation of various organic pollutants (Methylene Blue, Tetracycline, Ciprofloxacin, Rhodamine B, and their mixture), as well as Congo Red, with low catalyst dosage and visible light irradiation time, demonstrates the high performance and versatility of this nanocomposite. This research highlights the potential of Lys-rGO in compositing with semiconductors to design multifunctional catalysts for cost-effective sustainable water purification technologies.

Comparative Analysis of Polyphenolic Profile and Chemopreventive Potential of Hemp Sprouts, Leaves, and Flowers of the Sofia Variety.

This study investigates the phytochemical composition and biological activities of hemp (Cannabis sativa L.) leaves, flowers' methanolic extracts from the Sofia variety, and its sprouts cultivated under different light conditions (natural light, darkness, blue, and white LED light for 5, 7, and 9 days). Phytochemical analysis using HPLC identified four key polyphenolic compounds in sprouts' extracts: chlorogenic, caffeic, and gallic acids, and myricetin, with a predomination of the chlorogenic acid. In contrast, leaves and flowers' extracts contained cannflavins A and B and chlorogenic, p-coumaric, and ferulic acids, with a significant presence of isochlorogenic acid. Antioxidant capacity, assessed by FRAP method, revealed higher antioxidant potential in leaves compared to flowers and sprouts, with sprouts grown under blue and white LED lights exhibiting the highest activity. Cytotoxic activity was evaluated on human colon cancer cell lines (HT29, HCT116, DLD-1) and normal colon epithelial cells (CCD 841 CoN). Results demonstrated significant and selective cytotoxicity against cancer cell lines, with leaves showing more pronounced effects than flowers, and sprouts only moderate activity. All samples revealed an anti-inflammatory effect in vitro. To conclude, sprouts, leaves, and flowers of the Sofia hemp may be considered promising products for chemoprevention in the future.

Effects of light on reproduction of the Mediterranean medicinal leech, Hirudo verbana Carena, 1820: do circadian rhythm disruptions positively affect reproductive performance of leeches?

ABSTRACT This study aimed to assess the impact of light on the reproductive performance of leeches for the first time using the Mediterranean medicinal leech Hirudo verbana Carena, 1820, which is important in medicinal leech aquaculture. Gravid leeches were subjected to three different light conditions: 24-h Light, 24-h Dark, and Daylight (14-h light and 10-h dark) for 11 weeks. Gravidity ended at the 8th week for the Dark (5.33 ± 0.38 weeks) and Daylight (5.41 ± 0.29 weeks) groups, whereas it persisted for 11 weeks in the Light group (6.75 ± 0.51 weeks) (p = 0.031). In comparison to the Daylight group (cocoons: 40, offspring: 538), the Light (cocoons: 50, offspring: 723) and Dark (cocoons: 45, offspring: 576) groups achieved a greater yield of cocoons (p = 0.312) and offspring (p = 0.323). We invite discussion on the notion that the enhanced reproductive capacity of leeches in full light and full dark conditions, as opposed to daylight, may be attributed to the disturbance of their circadian rhythms.

Microglia undergo molecular and functional adaptations to dark and light phases in male laboratory mice

Microglia are increasingly recognized to contribute to brain health and disease. Preclinical studies using laboratory rodents are essential to advance our understanding of the physiological and pathophysiological roles of these cells in the central nervous system. Rodents are nocturnal animals, and they are mostly maintained in a defined light–dark cycle within animal facilities, with many laboratories investigating the molecular and functional profiles of microglia exclusively during the animals’ light (sleep) phase. However, only a few studies have considered possible differences in microglial functions between the active and sleep phases. Based on initial evidence suggesting that microglial intrinsic clock genes can affect their phenotypes, we sought to investigate differences in transcriptional, proteotype and functional profiles of microglia between light (sleep) and dark (active) phases, and how these changes are affected in pathological models. We found marked transcriptional and proteotype differences between microglia harvested from male mice during the light or dark phase. Amongst others, these differences related to genes and proteins associated with immune responses, motility, and phagocytosis, which were reflected by functional alterations in microglial synaptic pruning and response to bacterial stimuli. Possibly accounting for such changes, we found RNA and protein regulation in SWI/SNF and NuRD chromatin remodeling complexes between light and dark phases. Importantly, we also show that the time of microglial sample collection influences the nature of microglial transcriptomic changes in a model of immune-mediated neurodevelopmental disorders. Our findings emphasize the importance of considering diurnal factors in studying microglial cells and indicate that implementing a circadian perspective is pivotal for advancing our understanding of their physiological and pathophysiological roles in brain health and disease.

Interpreting 95 GeV di-photon/bb¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ b\\overline{b} $$\\end{document} excesses as a lightest Higgs boson of the MRSSM

The Minimal R-symmetric Supersymmetric Standard Model (MRSSM) is a well motivated BSM model which can accommodate the observed 125 GeV Higgs boson in agreement with electroweak precision observables, in particular with the W boson mass and T parameter. In the 2016 paper we showed that the SM-like 125 GeV Higgs state can be also realised as the second-to-lightest scalar of the MRSSM, leaving room for another sub-100 GeV state. Motivated by the recent ATLAS and CMS observation of the di-photon excess at a mass of around 95 GeV we investigate the possibility whether this could be the lightest CP-even MRSSM scalar in a variation of our benchmarks presented in the 2016 work. We show that such a state can also simultaneously explain the excess in the bb¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ b\\overline{b} $$\\end{document} final state observed around the same mass value at LEP. Due to the R-symmetric nature of the model, a light singlet-like Higgs state leads necessarily to a light bino-singlino Dirac dark matter candidate, which can give a correct relic density while evading current experimental bounds. Dark matter and LHC searches place further bounds on this scenario and point to parameter regions which are viable and of interest for the LHC Run III and upcoming dark matter experiments.

Antibacterial Activity of Visible Light Responsive‐Silver‐Nanoparticle/Titania Composite Thin Films with Unprecedently Higher Amounts of Silver

AbstractTo study the antibacterial efficacy of metallic Ag nanoparticle/titania (Ag‐NP)/TiO2 composite thin films against Escherichia coli (ATCC 25922), COMP‐Agn with various amounts of Ag (10 mol% ≤ n ≤ 80 mol%) are fabricated on a quartz glass substrate at 600 °C using the molecular precursor method. The films are characterized by X‐ray diffraction, X‐ray photoelectron, scanning electron microscopy, transmission electron microscopy, photoluminescence, and UVvis techniques. The analysis reveals that the films are composed of metallic Ag‐NPs embedded in a mixture of anatase and rutile matrix, with a volumetric fraction of Ag ranging from 0.18 to 0.68. The antibacterial activity of the TiO2 thin film and COMP‐Agn are determined by disk diffusion and viable cell count methods. Neither pure TiO2 nor pure Ag films exhibit any discernible antibacterial under dark and visible light. The antibacterial of Ag content in composite films is observed to persist for a maximum increase of 70%. The model is proposed on the basis of photoexcited electron transfer from Ag NPs to the TiO2 conduction band of COMP‐Agn, which clarifies the main factors affecting the photoresponse and the excellent response to visible light via surface plasmon resonance.

Research Note: Effects of different light-emitting diode lights during egg incubation on hatching performance and embryo development in White King pigeons

The light provide during incubation can influence hatching characteristics (hatching time, hatchability, etc.) and embryo development in chickens, geese, and turkeys. However, relevant studies on this factor in pigeons are lacking. This study investigated the effects of in ovo photostimulation during embryogenesis on hatching performance, squab quality, and embryo development in pigeons. 400 eggs from paired- bred pigeons were randomly distributed into 4 incubation lighting treatments, with 2 replicates per treatment. The treatments included dark as a control (NL), 12-h light, and 12-h dark photoperiods of white light (WL), red light (RL), and green light (GL) (100 lx at egg level) during the first 15 d of incubation. A total of 1,600 eggs in 4 batches from White King pigeons were used. The results showed that hatching time of the WL group was significantly shorter than that of the dark light group (P < 0.05). The hatchability of fertile eggs in the WL group was significantly higher (P < 0.05), whereas the hatchability of fertile eggs in the RL group was significantly lower (P < 0.05) than that of in the control group. Light stimulation had no effect on time to 90% hatching or average hatching time (P > 0.05). In addition, the hatch window was not extended by light stimulation (P > 0.05). The group incubated under GL showed an increase in embryo weight and relative leg muscle on embryonic d 14 and the hatching day compared to the dark incubation (P < 0.05). Green light stimulated the heart and liver development during the early and middle stages of embryogenesis. It was concluded that white light stimulation during embryogenesis accelerated the hatching process, whereas monochromatic green light had a positive effect on embryo development. Our findings provide important guidance for developing light protocols for pigeon egg incubation.

Temperature and LED lightning affect the regeneration of somatic embryo-derived sporophytes on the internode explants of the tree fern Cyathea delgadii Sternb.

The influence of the temperature and different light qualities emitted by light-emitting diodes (LEDs) and fluorescent lamps (Fl) on the micropropagation of the tree fern Cyathea delgadii was evaluated. The most efficient somatic embryo production was obtained on internode explants at 22 °C. The optimal temperature range for obtaining well-developed plants was 24–28 °C. This stimulated the elongation and development of the first leaf and the formation of the next leaf and roots primordia. Temperatures lower than 24 °C and higher than 28 °C inhibited the formation of young sporophyte organs and delayed their development. The RBUV (35% red, 15% blue, and 50% UV) and B (100% blue) lights and Fl light were beneficial for the sporophyte production on internode explants. However, plants obtained under RBUV light were undeveloped. The white LED light stimulated the number of explants capable of gametophyte production and development. The RB light (70% red and 30% blue) enhanced the number of roots of newly-formed plants. Most of the LED lights tested had a good impact on root elongation compared to Fl light and constant darkness. The R light (100% red) benefits leaf development and elongation. Research shows that temperature and LED lightning play a significant role in the process of morphogenesis in C. delgadii, significantly affecting the embryogenic competence of somatic cells and the development of sporophytes.