Variation Of Light Intensity Research Articles

Period induced reflectance tuning in transparent gold metasurfaces

Gold (Au) nanodisk arrays are modeled and fabricated for tunable near infrared reflectance with high visible transmittance. Simulations are performed in the visible and near infrared regimes between 400 and 2000 nm with varying period of nanostructures. A progressive increase in period of up to three times the diameter of the nanodisks on polymer and quartz substrates is presented. As a result, an increase in visible transmittance with a decrease in near infrared reflectance peak intensity is observed. Modeling results exhibit a high average visible transmittance of 91.5% (400–700 nm) and average reflectance of 62.9% (750–2000 nm) with diameter (D) variations from D=120 nm to D=500 nm with a period (P) equal to twice the diameter, P=2D for a polymer substrate. Electric field intensities exhibit an increase with a decrease in the period between individual nanostructures for constant unit cell dimensions. Alongside simulations, electron beam lithography and evaporation processes are utilized for the patterning and fabrication. Optical characterizations including scanning electron microscopy (SEM) and atomic force microscopy (AFM) of selected metasurfaces on quartz are performed. For a specific period and diameter, the fabricated metasurfaces exhibit near infrared reflectance having a good agreement with the simulated results about plasmonic wavelengths. Such metasurfaces offer potential to be deployed for applications that require selective reflectance intensities in the near infrared range with high visible transmittance, such as controlled environment agriculture (CEA) or multi spectral near infrared sensing. With tunability over a broadband (750–2500 nm), this simple and fabrication-friendly model may be used as a theoretical guide in quantifying specific design parameters with varying light intensity configurations.

Outdoor biohydrogen production by thermotolerant Rhodopseudomonas pentothenatexigens KKU-SN1/1 in a cluster of ten bioreactors system.

In tropical regions, the viability of outdoor photo-fermentative biohydrogen production faces challenges arising from elevated temperatures and varying light intensity. This research aimed to explore how high temperatures and outdoor environments impact both biohydrogen production and the growth of purple non-sulfur bacteria. Our findings revealed the potential of Rhodopseudomonas spp. as a robust outdoor hydrogen-producing bacteria, demonstrating its capacity to thrive and generate biohydrogen even at 40°C and under fluctuating outdoor conditions. Rhodopseudomonas harwoodiae NM3/1-2 produced the highest cumulative biohydrogen of 223mL/L under anaerobic light conditions at 40°C, while Rhodopseudomonas harwoodiae 2M had the highest dry cell weight of 2.93g/L. However, R. harwoodiae NM3/1-2 demonstrated the highest dry cell weight of 3.99g/L and Rhodopseudomonas pentothenatexigens KKU-SN1/1 exhibited the highest cumulative biohydrogen production of 400mL/L when grown outdoors. In addition, the outdoor enhancement of biohydrogen production was achieved through the utilization of a cluster of ten bioreactors system. The outcomes demonstrated a notable improvement in biohydrogen production efficiency, marked by the highest daily biohydrogen production of 493mL/Ld by R. pentothenatexigens KKU-SN1/1. Significantly, the highest biohydrogen production rate was noted to be 17 times greater than that observed in conventional batch production methods. This study is the first to utilize R. pentothenatexigens and R. harwoodiae for sustained biohydrogen production at high temperatures and in outdoor conditions over an extended operational period. The successful utilization of a clustered system of ten bioreactors demonstrates potential to scale-up for industrial biohydrogen production.

Life Cycle Assessment of Exopolysaccharides and Phycocyanin Production with Arthrospira platensis

In the pursuit of sustainable solutions for contemporary environmental challenges arising from the increasing global demand for energy, this study delves into the potential of cyanobacteria, specifically Arthrospira platensis (commonly known as “spirulina”), as a versatile resource. Employing a life cycle assessment (LCA) in accordance with the ISO 14044:2006 standard and employing both midpoint and endpoint indicators, the study comprehensively evaluates environmental impacts. The research explored a range of scenarios, specifically investigating variations in light intensity and harvesting volume. These investigations were carried out using a pilot-scale photobioreactor, specifically an airlift reactor system featuring a horizontal tubular downcomer. The primary focus is on extracting valuable compounds, namely exopolysaccharides and phycocyanin. It emphasized the extraction of value-added products and strategic integration with a biogas plant for process heat, contributing to developing a sustainable supply network and offering insights into environmentally conscious algae cultivation practices with implications for renewable energy and the production of valuable products. The results emphasize the project’s potential economic feasibility with minimal energy impact from by-product extraction. The environmental assessment identifies marine ecotoxicity and fossil resource depletion as principal impacts, predominantly influenced by upstreaming and harvesting stages. After conducting comparisons across various scenarios, it was found that cultivations under higher light intensities have a lower environmental impact than cultivations with low light supply. However, regardless of light intensity, processes with shorter harvesting cycles tend to have a smaller environmental impact compared to processes with longer harvesting cycles. Overall, this research contributes a nuanced and realistic perspective, fostering informed decision-making in sustainable algae cultivation practices, with implications for renewable energy and valuable compound production.

Photo-activated dynamic isomerization induced large density changes in liquid crystal polymers: A molecular dynamics study.

We use molecular dynamics simulations to unravel the physics underpinning the light-induced density changes caused by the dynamic trans-cis-trans isomerization cycles of azo-mesogens embedded in a liquid crystal polymer network, an intriguing experimental observation reported in the literature. We employ two approaches, cyclic and probabilistic switching of isomers, to simulate dynamic isomerization. The cyclic switching of isomers confirms that dynamic isomerization can lead to density changes at specific switch-time intervals. The probabilistic switching approach further deciphers the physics behind the non-monotonous relation between density reduction and light intensities observed in experiments. Light intensity variations in experiments are accounted for in simulations by varying the trans-cis and cis-trans isomerization probabilities. The simulations show that an optimal combination of these two probabilities results in a maximum density reduction, corroborating the experimental observations. At such an optimal combination of probabilities, the dynamic trans-cis-trans isomerization cycles occur at a specific frequency, causing significant distortion in the polymer network, resulting in a maximum density reduction.

Photostriction effect and electric properties of La-doped PMN-PT transparent ferroelectric ceramics

ABSTRACT Ferroelectric ceramics display a remarkable photostriction effect, which could facilitate the prevention of electromagnetic interference and promote the integration and miniaturization of actuator systems, indicating potential applications in glimmer sensors. In this work, highly transparent La-doped 0.9Pb(Mg1/3Nb2/3)O3-0.1PbTiO3 (0.9PMN–0.1PT) ceramics were synthesized using a solid-state reaction method in an oxygenated atmosphere. XRD and SEM were used to analyze the phase structure of the dense samples, which displayed a pure perovskite structure, with no trace of a pyrochlore phase. With La doping, the phase transition temperature shows a decreasing trend, and its dielectric constant could reach up to 20,000. The P-E loop of the samples was gradually refined into a straight line with an increase in the doping amount. After La doping, the transparency of the 0.9PMN–0.1PT ceramics was significantly enhanced and reached up to 61% at the near-infrared band. Finally, the photogenerated voltage and deformation of the La-doped 0.9PMN–0.1PT ceramics were investigated under ultraviolet light of various intensities. After 20 s of irradiation at an intensity of 800 mW/cm2, the maximum voltage and deformation, with values of 40 V and 250 nm, respectively, were both found in the 1%La-doped 0.9PMN–0.1PT ceramics.

Online detection of eggshell cracks using adaptive light‐source intensity

AbstractUnder the fixed light source intensity (LSI), eggshell thickness difference results in excessive exposure or darkening in imaging, which affects the accuracy of crack identification. To optimize it, a solution involves the utilization of an innovative adaptive light source for optical imaging is proposed. A multi function station is adopted. Among them, one station serves as a reference workstation is utilized to obtain the average grayscale value of the eggs image. The other sub stations serve as detection workstations to acquire and detect the panoramic images of the eggshell. By using the red component average grayscale as a reference to adjust the LSI in the remaining sub stations, imaging consistency is effectively. Moreover, a dual threshold segmentation algorithm was developed to attenuate the dark spot, thereby improving crack detection. Experiments results demonstrating the proposed method significantly improving the detection accuracy of non microcracked eggs while achieving approximately 90% and 92% detection accuracy for intact and cracked eggs, respectively.Practical ApplicationsThere are a few studies on the consistency of light for eggs, and in actual online detection, the light source is often set to a fixed light intensity value, which can lead to overexposure or over‐darkening of the egg image due to variations in the eggshell thickness, and both overexposed and over‐darkened images will result in decreased accuracy of crack recognition. This study designed and built an online detection system for eggshell cracks based on variable light intensity. Therefore, the system not only can help to improve the crack recognition rate of poultry eggs and improve their quality but also would help to promote the development of the commercialization of poultry eggs, which has a broad application prospect.

Light-dependent regulation of neurotransmitter release from rod photoreceptor ribbon synapses involves an interplay of Complexin 4 and Transducin with the SNARE complex.

Adaptation of photoreceptor sensitivity to varying light intensities is a fundamental requirement for retinal function and vision. Adaptive mechanisms in signal transduction are well described, but little is known about the mechanisms that adapt the photoreceptor synapse to changing light intensities. The SNARE complex regulators Complexin 3 and Complexin 4 have been proposed to be involved in synaptic light adaptation by limiting synaptic vesicle recruitment and fusion. How this Complexin effect is exerted is unknown. Focusing on rod photoreceptors, we established Complexin 4 as the predominant Complexin in the light-dependent regulation of neurotransmitter release. The number of readily releasable synaptic vesicles is significantly smaller in light than in dark at wildtype compared to Complexin 4 deficient rod photoreceptor ribbon synapses. Electrophysiology indicates that Complexin 4 reduces or clamps Ca2+-dependent sustained synaptic vesicle release, thereby enhancing light signaling at the synapse. Complexin 4 deficiency increased synaptic vesicle release and desensitized light signaling. In a quantitative proteomic screen, we identified Transducin as an interactor of the Complexin 4-SNARE complex. Our results provide evidence for a presynaptic interplay of both Complexin 4 and Transducin with the SNARE complex, an interplay that may facilitate the adaptation of synaptic transmission to light at rod photoreceptor ribbon synapses.

Variable carbon isotope fractionation of photosynthetic communities over depth in an open-ocean euphotic zone

Marine particulate organic carbon (POC) contributes to carbon export, food webs, and sediments, but uncertainties remain in its origins. Globally, variations in stable carbon isotope ratios (δ13C values) of POC between the upper and lower euphotic zones (LEZ) indicate either varying aspects of photosynthetic communities or degradative alteration of POC. During summertime in the subtropical north Atlantic Ocean, we find that δ13C values of the photosynthetic product phytol decreased by 6.3‰ and photosynthetic carbon isotope fractionation (εp) increased by 5.6‰ between the surface and the LEZ-variation as large as that found in the geologic record during major carbon cycle perturbations, but here reflecting vertical variation in δ13C values of photosynthetic communities. We find that simultaneous variations in light intensity and phytoplankton community composition over depth may be important factors not fully accounted for in common models of photosynthetic carbon isotope fractionation. Using additional isotopic and cell count data, we estimate that photosynthetic and non-photosynthetic material (heterotrophs or detritus) contribute relatively constant proportions of POC throughout the euphotic zone but are isotopically more distinct in the LEZ. As a result, the large vertical differences in εp result in significant, but smaller, differences in the δ13C values of total POC across the same depths (2.7‰). Vertical structuring of photosynthetic communities and export potential from the LEZ may vary across current and past ocean ecosystems; thus, LEZ photosynthesis may influence the exported and/or sedimentary δ13C values of both phytol and total organic carbon and affect interpretations of εp over geologic time.

Time resolved calorimetric investigations of photoinduced isomeric molecular changes in the nematic phase of an azobenzene compound

By monitoring the time dependence of the thermal conductivity of a p,p’-diheptylazobenzene sample irradiated with UV light of various intensities, a quantitative study is presented on the effects played by the photo-induced trans to cis isomerization on the degree of the homeotropic alignment in its nematic phase. In particular, the kinetics of the changes eventually leading to the nematic–isotropic phase transformation has been investigated. Unlike the case of the thermal diffusivity analyzed in a recent study, the thermal conductivity analysis has enabled the quantitative evaluation of the trans–cis transformation rates since it is not affected by the specific heat critical behavior and, therefore, it is determined only by changes in the molecular structure induced by the photo-isomerization. The study has been possible thanks to the peculiarity of the adopted photopyroelectric calorimetric setup that enabled both the calorimetric evaluations, as well as the sample texture characterization, to be performed during the UV illumination of the sample.

A self-adjusting method to generate daily consistent nighttime light data for the detection of short-term rapid human activities

Nighttime light (NTL) has become an emerging indicator of the magnitude and changes in human settlement and activities. A recently released Lunar-BRDF-corrected NTL product, Black Marble VNP46A2, with enhanced temporal (daily) and spatial (15 arc-second) resolutions, has the potential to monitor human reactions to short-term events with rapid light intensity variations. However, the VNP46A2 NTL exhibits unexpected large daily variations resulting from two residual errors (spatial observational coverage mismatch and angular effect), leading to difficulty in extracting true change signals of NTL time series. In this study, we developed a Self-adjusting method featuring Filter and Angular effect Correction (SFAC) to eliminate the two errors without any auxiliary data. The proposed adjusted-average filtering effectively reduced the mismatch error and enhanced data consistency with less “blooming effect” than other filtering methods. The normalized standard deviation of daily NTL was largely reduced in the selected airport areas after filtering. The variation caused by the angular effect has also been corrected by a relative calibration method using the 16 days' cycle of satellite view angles, which apparently decreases the dependence of the light intensity on the view angles. We further explored and found that the detectability of short-term rapid events (i.e., festival/event celebration with increased NTL and power outage with reduced NTL) using SFAC-corrected VNP46A2 outperformed the original product. More detailed information on rapid events and evolutions in small spaces is expected to be digested with the high-quality, SFAC-corrected daily consistent VNP46A2 NTL data.

EFFECT OF INSTANTANEOUS LIGHT INTENSITY AFTER MAGNESIUM SUPPRESSION IN TOMATO AND BELL PEPPER CULTIVATION

Plants dynamically respond to varying light intensities, which may further interact with their nutrient status to affect gas exchange parameters. This study investigated the combined effect of instantaneous light intensity and magnesium suppression on tomato and bell pepper cultivation. Two independent experiments were conducted in September 2022 using the tomato variety Mariana (Sakata®) and bell pepper variety Magali R (Sakata®) at the Faculty of Agricultural and Technological Sciences, Dracena, São Paulo, Brazil. A completely randomized 2x5 factorial design was employed, with the first factor being the presence/absence of magnesium in the nutrient solution and the second factor being four light intensities: 0 (control), 600, 1200, and 1800 μmol m⁻² s⁻¹ photosynthetically active radiation (PAR) applied instantaneously using an IRGA device. Magnesium deficiency was confirmed to be a limiting factor for gas exchange responses in both tomato and pepper crops. Notably, the light intensity of 1200 μmol m⁻² s⁻¹ PAR elicited the most optimal gas exchange performance in both plant species.

Seedling Growth Stress Quantification Based on Environmental Factors Using Sensor Fusion and Image Processing

Understanding the diverse environmental influences on seedling growth is critical for maximizing yields. The need for a more comprehensive understanding of how various environmental factors affect seedling growth is required. Integrating sensor data and image processing techniques offers a promising approach to accurately detect stress symptoms and uncover hidden patterns, enhancing the comprehension of seedling responses to environmental factors. The objective of this study was to quantify environmental stress symptoms for six seedling varieties using image-extracted feature characteristics. Three sensors were used: an RGB camera for color, shape, and size information; a thermal camera for measuring canopy temperature; and a depth camera for providing seedling height from the image-extracted features. Six seedling varieties were grown under controlled conditions, with variations in temperature, light intensity, nutrients, and water supply, while daily automated imaging was conducted for two weeks. Key seedling features, including leaf area, leaf color, seedling height, and canopy temperature, were derived through image processing techniques. These features were then employed to quantify stress symptoms for each seedling type. The analysis of stress effects on the six seedling varieties revealed distinct responses to environmental stressors. Integration of color, size, and shape parameters established a visual hierarchy: pepper and pak choi seedlings showed a good response, cucumber seedlings showed a milder response, and lettuce and tomato seedlings displayed an intermediate response. Pepper and tomato seedlings exhibited a wide range of growth stress symptoms, at 13.00% to 83.33% and 2.96% to 70.01%, respectively, indicating considerable variability in their reactions to environmental stressors. The suggested classification approach provides valuable groundwork for advancing stress monitoring and enabling growers to optimize environmental conditions.

Effects of Environmental Enrichments on Welfare and Hepatic Metabolic Regulation of Broiler Chickens.

The aims of this study were to find suitable environmental enrichment (EE) and evaluate the combined effect of two EEs, variable light intensity (VL) lighting program and EH, on mental health and hepatic metabolic regulation in commercial broilers. To find the advantageous EEs for broilers, three different EEs (board, hut, and ramp) were tested in trial 1. EEs were placed and the engagement of birds to EEs, dustbathing behavior, and daily physical activity were observed. Birds treated with huts showed higher engagement than the board- or ramp-treated birds (p < 0.05). The results of dustbathing behavior and daily physical activity indicated that the environmental hut (EH) is the most favorable enrichment for broilers. In the second trial, to test the effect of EHs on mental health and hepatic metabolic conditions, the brain and liver were sampled from the four treatment birds (20 lx_Con, 20 lx_Hut, VL_Con and VL_Hut) on day 42. The lower expression of TPH2 (tryptophan hydroxylase 2) of VL_Hut birds than those of VL_Con and 20 lx_Hut treated birds suggests the combining effect of EHs with the VL lighting program on the central serotonergic homeostasis of broilers. Reduced expressions of TH (tyrosine hydroxylase), GR (glucocorticoid receptor), BDNF (brain-derived neurotrophic factor) of VL_Hut treated birds compared to those of VL_Con and 20 lx_Hut birds suggest lower stress, stress susceptibility, and chronic social stress in VL_Hut treated birds. The expression of CPT1A (carnitine palmitoyl transferase 1) increased over three-fold in the liver of VL_Con birds compared to 20 lx_Con birds (p < 0.05). EHs treatment in VL birds (VL_Hut) significantly decreased CPT1A but not in 20 lx birds (20 lx_Hut). The expression of ACCα (acetyl-CoA carboxylase alpha) was significantly decreased in VL_Con birds compared to 20 lx_Con birds. There was no significant difference in the hepatic FBPase (fructose-1,6-bisphosphatase), GR, and 11β-HSD1 (11 β-hydroxysteroid dehydrogenease-1) expression between 20 lx_Con and VL_Con birds, but EHs significantly stimulated GR in 20 lx_Hut birds, and stimulated FBPase and 11β-HSD1 expression in the VL_Hut birds compared to 20 lx_Con birds, suggesting that the VL lighting program reduced fatty acid synthesis and increased fatty acid β-oxidation in the broilers' liver and VL_Hut improved the hepatic de novo glucose production. Taken together, the results suggest that the stimulated voluntary activity by EHs in the light-enriched broiler house improved mental health and hepatic metabolic function of broilers and may indicate that the improved hepatic metabolic function contributes to efficient nutritional support for broilers.

Natural genetic variation in GLK1-mediated photosynthetic acclimation in response to light

BackgroundGOLDEN-like (GLK) transcription factors are central regulators of chloroplast biogenesis in Arabidopsis and other species. Findings from Arabidopsis show that these factors also contribute to photosynthetic acclimation, e.g. to variation in light intensity, and are controlled by retrograde signals emanating from the chloroplast. However, the natural variation of GLK1-centered gene-regulatory networks in Arabidopsis is largely unexplored.ResultsBy evaluating the activities of GLK1 target genes and GLK1 itself in vegetative leaves of natural Arabidopsis accessions grown under standard conditions, we uncovered variation in the activity of GLK1 centered regulatory networks. This is linked with the ecogeographic origin of the accessions, and can be associated with a complex genetic variation across loci acting in different functional pathways, including photosynthesis, ROS and brassinosteroid pathways. Our results identify candidate upstream regulators that contribute to a basal level of GLK1 activity in rosette leaves, which can then impact the capacity to acclimate to different environmental conditions. Indeed, accessions with higher GLK1 activity, arising from habitats with a high monthly variation in solar radiation levels, may show lower levels of photoinhibition at higher light intensities.ConclusionsOur results provide evidence for natural variation in GLK1 regulatory activities in vegetative leaves. This variation is associated with ecogeographic origin and can contribute to acclimation to high light conditions.

Metabolomic and Growth Responses of Houttyunia cordata to Varying Light Intensities and Subsequent Effects on Fermented Products

Suitable light intensities were studied to enable sustainable and efficient cultivation of Houttuynia cordata with a high yield of bioactive compounds which later can be a good quality material for fermentation. To achieve this goal, the evaluation of physiological adaptation and elucidation of the metabolic alterations of Houttuynia cordata in response to different light intensities were conducted. Four-month-old H. cordata was exposed to 3 different light intensities: high light, control, and low light (100, 50 and 20 % natural irradiances, respectively). Physiological responses were measured using leaf gas exchange. The same leaf samples were either methanolic extracted for LC-QTOF-MS analysis to generate metabolite fingerprints or fermented for 3 months prior to quercetin quantification. High light treatment had the greatest effects on both the physiology and metabolisms of H. cordata compared to control and low light treatments. Compared to the control, the key results observed in high-light-grown H. cordata were a significant increase in photosynthesis, a decrease in relative chlorophyll contents, the enrichment of the top 3 metabolic pathways (phenylpropanoid biosynthesis, pyruvate metabolism and fatty acid degradation) and increasing quercetin concentrations in both fresh and fermented leaves. Metabolite fingerprints of high light-grown H. cordata were distinctively different from those of the other 2 treatments according to PCA and hierarchical clustering analysis. In conclusion, H. cordata responded to high light intensity by enriching the phenylpropanoid biosynthetic pathway to elevate sunscreen pigments. Additional acetyl-CoA generated from pyruvate metabolism and fatty acid degradation was a key supporting factor in the above response. As high quercetin concentration was observed in both fresh and fermented leaves, this will lead to quality improvement of the fermented products. HIGHLIGHTS The remarkable effects of light intensities on Houttuynia cordata growth and abundance of bioactive compounds are substantial, but the underlying mechanism has never been investigated. Metabolomics technology was applied to gain insight into light-induced metabolic reconfiguration. GRAPHICAL ABSTRACT

Intrinsic kinetic model with variable light intensity of the emerging pollutants degradation in a photocatalytic differential reactor with immobilized TIO2: Experiments and CFD

AbstractHeterogeneous photocatalysis is an alternative to mineralizing emerging pollutants. The present study focuses on the kinetic model of salicylic acid photocatalytic degradation in an aqueous solution as a function of pollutant concentration and light intensity. The intrinsic kinetic model parameters were determined using a differential photocatalytic reactor with immobilized TiO2 based on experiments and numerical simulations. Five degradation experiments with different light intensities were performed for a turbulent flow rate of 4.7 L/min and salicylic acid concentration of 20 mg/L. Light intensities used for the kinetic experiments were obtained by computational fluid dynamics (CFD) simulation using the radiation transfer equation that was pre‐validated. The TiO2 immobilized method presents low leaching of the catalyst and good degradation efficiency. The intrinsic kinetic model showed to be first‐order both for the pollutant concentration and for the light intensity and can be applied in simulation to optimize and design photocatalytic reactors.

Light Intensity Modulates the Functional Composition of Leaf Metabolite Groups and Phyllosphere Prokaryotic Community in Garden Lettuce (Lactuca sativa L.) Plants at the Vegetative Stage.

Light intensity primarily drives plant growth and morphogenesis, whereas the ecological impact of light intensity on the phyllosphere (leaf surface and endosphere) microbiome is poorly understood. In this study, garden lettuce (Lactuca sativa L.) plants were grown under low, medium, and high light intensities. High light intensity remarkably induced the leaf contents of soluble proteins and chlorophylls, whereas it reduced the contents of leaf nitrate. In comparison, medium light intensity exhibited the highest contents of soluble sugar, cellulose, and free amino acids. Meanwhile, light intensity resulted in significant changes in the composition of functional genes but not in the taxonomic compositions of the prokaryotic community (bacteria and archaea) in the phyllosphere. Notably, garden lettuce plants under high light intensity treatment harbored more sulfur-cycling mdh and carbon-cycling glyA genes than under low light intensity, both of which were among the 20 most abundant prokaryotic genes in the leaf phyllosphere. Furthermore, the correlations between prokaryotic functional genes and lettuce leaf metabolite groups were examined to disclose their interactions under varying light intensities. The relative abundance of the mdh gene was positively correlated with leaf total chlorophyll content but negatively correlated with leaf nitrate content. In comparison, the relative abundance of the glyA gene was positively correlated with leaf total chlorophyll and carotenoids. Overall, this study revealed that the functional composition of the phyllosphere prokaryotic community and leaf metabolite groups were tightly linked in response to changing light intensities. These findings provided novel insights into the interactions between plants and prokaryotic microbes in indoor farming systems, which will help optimize environmental management in indoor farms and harness beneficial plant-microbe relationships for crop production.

Shining a Light on Symbiosis: N-Fixing Bacteria Boost Legume Growth under Varied Light Conditions

Legumes are a diverse and important group of plants that play a vital role in agriculture, food security, and environmental sustainability. Rhizobia are symbiotic bacteria that form nitrogen-fixing nodules on legume roots, providing the plant with a valuable source of nitrogen. Phenolic acids are a group of secondary metabolites produced by plants that have a wide range of biological functions, including defense against pests and diseases, tolerance to abiotic stresses, and nutrient uptake. In the context of climate change and the imperative for sustainable agriculture, this study delves into the dynamic responses of legume species to varying light intensities and their intricate interactions with soil microorganisms. We investigated the impact of light intensity and rhizobial inoculation on the biomass, nitrate reductase, acid phosphatase, and production of phenolic acids in the roots of four legume species, Trifolium repens, Vicia sativa, Ornithopus compressus, and Coronilla juncea. Plants were grown under three light intensity regimes (low, medium, and high) and inoculated with either rhizobia or a non-inoculated control. The results highlight that shaded-light-adapted species, T. repens and V. sativa, increased root exudate production when exposed to high light intensity. This response aligns with their mining strategy, effectively allocating resources to optimize nutrient acquisition under varying conditions. In contrast, species hailing from well-illuminated environments, O. compressus and C. juncea, displayed distinct strategies by significantly increasing biomass under high irradiance, capitalizing on the available light and nutrients. The mining strategy of legumes emerged as a central theme, influencing biomass production, nitrogen dynamics, and enzymatic activities. The strong correlations between biomass and total nitrogen accumulation underscore the role of the mining strategy in efficient nutrient acquisition. Inoculated plants, which rely more on biological nitrogen fixation (BNF), exhibited lower δ15N values, indicative of a successful mining strategy to acquire and utilize atmospheric nitrogen. Enzymatic activities and phenolic acids exhibited significant interspecies variations, reflecting the adaptability of legumes to different light conditions. The findings of this study could be used to develop new strategies for improving legume stress tolerance, nutrient uptake capacity, and rhizosphere health.

Computational dissection of genetic variation modulating the response of multiple photosynthetic phenotypes to the light environment

BackgroundThe expression of biological traits is modulated by genetics as well as the environment, and the level of influence exerted by the latter may vary across characteristics. Photosynthetic traits in plants are complex quantitative traits that are regulated by both endogenous genetic factors and external environmental factors such as light intensity and CO2 concentration. The specific processes impacted occur dynamically and continuously as the growth of plants changes. Although studies have been conducted to explore the genetic regulatory mechanisms of individual photosynthetic traits or to evaluate the effects of certain environmental variables on photosynthetic traits, the systematic impact of environmental variables on the dynamic process of integrated plant growth and development has not been fully elucidated.ResultsIn this paper, we proposed a research framework to investigate the genetic mechanism of high-dimensional complex photosynthetic traits in response to the light environment at the genome level. We established a set of high-dimensional equations incorporating environmental regulators to integrate functional mapping and dynamic screening of gene‒environment complex systems to elucidate the process and pattern of intrinsic genetic regulatory mechanisms of three types of photosynthetic phenotypes of Populus simonii that varied with light intensity. Furthermore, a network structure was established to elucidate the crosstalk among significant QTLs that regulate photosynthetic phenotypic systems. Additionally, the detection of key QTLs governing the response of multiple phenotypes to the light environment, coupled with the intrinsic differences in genotype expression, provides valuable insights into the regulatory mechanisms that drive the transition of photosynthetic activity and photoprotection in the face of varying light intensity gradients.ConclusionsThis paper offers a comprehensive approach to unraveling the genetic architecture of multidimensional variations in photosynthetic phenotypes, considering the combined impact of integrated environmental factors from multiple perspectives.

Comparative Transcriptome Analysis Reveals Changes in Gene Expression Associated with Anthocyanin Metabolism in Begonia semperflorens under Light Conditions

Anthocyanins, recognized as stress indicators, particularly under high-light conditions, play a pivotal role in plant stress responses. The advent of transcriptomics has opened avenues to elucidate the mechanisms underlying high light-induced anthocyanin biosynthesis. This study delved into transcriptomic changes in Begonia semperflorens leaves under varying light intensities: 950–9600 lx (TL_100), 6800–7000 lx (HS_75), and 4300–4500 lx (LS_25). To confirm the expression profiles of the key genes, we chose 12 critical genes associated with anthocyanin production for quantitative reverse transcription PCR (qRT-qPCR) analysis. Following this, we measured the levels of anthocyanins to substantiate the findings from the gene expression analysis. The transcriptome assembly in this study was extensive, yielding 43,038 unigenes that collectively spanned about 49.83 million base pairs, with an average unigene length of 1157 bp and an N50 value of 1685 bp. This assembly facilitated a thorough functional annotation across seven distinct protein databases, leading to the classification of 16,363 unigenes into 58 different families of transcription factors. Our comparative analysis of the transcriptomes highlighted a substantial number of differentially expressed genes (DEGs): 5411 DEGs between HS_75 and TL_100 conditions, with 3078 showing increased expression and 2333 showing decreased expression; 4701 DEGs between LS_25 and TL_100, consisting of 2648 up-regulated and 2053 down-regulated genes; and 6558 DEGs between LS_25 and HS_75, with 3032 genes up-regulated and 3526 down-regulated. These DEGs were significantly involved in critical pathways, such as anthocyanin synthesis, plant hormone signaling, and other regulatory mechanisms. This study suggests that genes, including F3′H, MYB102, and SWEET1, could play vital roles in regulating anthocyanin synthesis in response to various light conditions, potentially impacting the expression levels of other genes, like WRKYs, ATHB12, and those similar to HSP.