Search Results (611)

The growing demand for sustainable bioprocesses highlights microalgae as a promising source of renewable feedstock. However, high energy use for artificial lighting limits the commercial viability of photobioreactor systems. This study proposes an energy-optimized framework for cultivating Mychonastes homosphaera using LED illumination. The optimization was performed using Response Surface Methodology (RSM) with a Face-Centered Central Composite Design (FCCCD) to assess the interactive effects of light intensity, duration, airflow rate, and nitrogen concentration on biomass and lipid productivity. The performance of LED wavelengths was compared for biomass, lipid productivity, and energy consumption. RSM models were statistically significant (p < 0.01), and ANOVA had a high coefficient of determination (R²) for all LEDs. Maximum biomass productivity was 512.0 ± 12.23 mg L⁻¹ day⁻¹ with cool-white, followed by pink (401.33 ± 10.48), blue (342.66 ± 3.53), and red (189.6 ± 1.36). Cool-white consumed the least energy (228.6 Wh day⁻¹) to produce the maximum biomass, compared to blue (235.05 Wh day⁻¹), pink (240.0 Wh day⁻¹), and red (240.0 Wh day⁻¹). Lipid content was highest under red (22.84%), followed by pink (17.39%), blue (15.82%), and cool-white (8.96%). However, lipid productivity was highest under pink (69.8 mg L⁻¹ day⁻¹), followed by blue (54.2 mg L⁻¹ day⁻¹), cool-white (45.86 mg L⁻¹ day⁻¹), and red (43.3 mg L⁻¹ day⁻¹). Full article

Grain amaranths are recalcitrant to conventional in vitro plant regeneration by organogenesis de novo or through somatic embryogenesis. Consequently, floral organogenesis by these methods, representing the culminating developmental point in angiosperms, is rarely achieved. In the present study, the manipulation of in vitro flowering was explored as part of a strategy designed to overcome grain amaranth’s regeneration recalcitrance. It led to an efficient and reproducible in vitro protocol in which half-longitudinally dissected zygotic embryos generated fully developed Amaranthus hypochondriacus (Ah) plants. The use of high-irradiance illumination with LED lamps with a 3:1 red–blue irradiance ratio was a critical factor, leading to a 70% rate of early flowering events under flowering-inhibiting long-day photoperiod conditions. Contrariwise, no flowering was induced under LED white lights. All in vitro flowering Ah plants yielded viable seeds. To understand the basic molecular mechanisms of the phenomenon observed, gene expression patterns and principal component analysis of key flowering-related genes were analyzed after cultivation in vitro for 4, 8, and 12 weeks under both lighting regimes. These coded for photoreceptors, photomorphogenetic regulators, embryogenic modulators, and flowering activators/repressors. The results highlighted the upregulation of key flowering-regulatory genes, including CONSTANS, FLOWERING LOCUS T, and LEAFY, together with the downregulation of the floral repressor TERMINAL FLOWER1. Ribosome biogenesis- and seed-development-related genes were also differentially expressed, supporting a key role in this process for protein synthesis and embryogenesis. A model is proposed to explain how this light-regulated molecular framework enables in vitro flowering and seed production in Ah plants kept under long-day photoperiods. Full article

High-mountain microalgae exhibit remarkable adaptability to extreme environments, making them promising candidates for sustainable biorefineries. We evaluated how photoperiod (12:12, 18:6, 24:0 h) and LED spectra (cool white, full spectrum, red–blue 4:1) affect growth and metabolite formation in Chlorella sp. UFPS019 and Scenedesmus sp. UFPS021. Biomass peaked in Chlorella under red–blue 18:6 (≈1.8 g L⁻¹) and in Scenedesmus under red–blue 24:0 (≈1.7 g L⁻¹), revealing species-specific responses. Carbohydrate fractions were maximized under red–blue 12:12 in both species, and continuous light (24:0) depressed carbohydrate content—most notably under full spectrum. Protein content was highest under red–blue 18:6 in Chlorella sp. and under red–blue 12:12–18:6 in Scenedesmus sp. Lipid fractions increased with light duration, peaking under red–blue 18:6–24:0 in Chlorella and under red–blue 18:6–24:0—with Cool White 24:0 also high—in Scenedesmus sp. Although extended illumination favored lipids, intermediate photoperiods (12:12–18:6) provided better productivity-to-energy trade-offs and broader metabolic profiles. These results show that tuning spectral composition and photoperiod to species-specific physiology enables the targeted, energy-aware production of proteins, carbohydrates, or lipids; red–blue at intermediate durations is a robust, energy-efficient regime, whereas longer exposures can be used strategically when lipid enrichment is prioritized. Full article

Canada goldenrod (Solidago canadensis L.), a short-day plant commonly cultivated as a cut flower, depends on proper lighting management to obtain long stems and higher commercial value. Thus, this study aimed to determine the effect of modifying the light spectrum through the installation of light-emitting diodes (LEDs) and the use of colored shade nets on the production and quality of Canada goldenrod stems. The treatments used were colored shade nets and different LED lighting treatments. Production per plant and productivity per square meter were determined. Twenty stems were selected and evaluated for: stem length; inflorescence length and width; number of floral ramets per inflorescence; number of leaves; stem base diameter (mm); and fresh stem biomass (g). Canada goldenrod plants require an extension of the light period with artificial lighting to produce higher-quality stems, regardless of whether the bulbs emit red or white light. The use of nets with 50% red and white shading promoted higher production and elongation of Canada goldenrod stems, with a production that reached up to 4.2 floral stems per plant and 100.3 floral stems per square meter using the red shade net and white LED. These floral stems were of high commercial standard, with a length of up to 81.35 cm with the red shade net and red LED, and were 31 cm in diameter for the inflorescences, approximately, under black or white shade nets and white or red LEDs. More robust floral stems with greater biomass were observed using any shade net color and LED lamps. Full article

Aronia melanocarpa is rich in anthocyanins, compounds with significant medicinal and industrial value, making it an attractive species for enhanced production. Compared with fruits or intact plants, callus tissue offers a uniform, controllable in vitro system that is particularly suitable for dissecting regulatory mechanisms under defined environmental conditions. Although light quality is known to influence anthocyanin biosynthesis, its specific regulatory mechanisms in A. melanocarpa remain unclear. In this study, callus tissues were cultured under six light regimes: full-spectrum LED, blue:red (5:1), red:blue (5:1), red:blue:white (1:1:1), red:white (5:1), and pure blue light. Anthocyanin content was quantified using the pH differential method, and the results showed that the blue:red (5:1) treatment produced the highest accumulation, reaching 14.06 mg/100 g. Transcriptome sequencing was then performed to compare the gene expression profiles between calli cultured under blue:red (5:1) light and those maintained in darkness. A total of 10,547 differentially expressed genes (DEGs) were identified, including 6134 upregulated and 4413 downregulated genes. Functional enrichment analysis indicated that these DEGs were mainly involved in anthocyanin biosynthesis and transport. Importantly, key structural genes such as PAL, C4H, 4CL, CHS, ANS, UFGT, and GST were significantly upregulated under blue:red (5:1) light, as further validated by qRT-PCR. Overall, our findings demonstrate that a blue:red (5:1) light ratio enhances anthocyanin accumulation by promoting the expression of biosynthetic and transport-related genes. This study not only provides new transcriptomic insights into the light-mediated regulation of secondary metabolism in A. melanocarpa callus, but also establishes a foundation for optimizing in vitro culture systems for sustainable anthocyanin production. Full article

This study aimed to evaluate the effects of specific LED light spectra on the growth and physiology of Changchuan No. 3 Capsicum annuum L. seedlings. The experimental design involved exposing pepper seedlings to six different spectral light combinations for 7, 14, and 21 days, with the treatments consisting of 2R1B1Y (red/blue/yellow = 2:1:1), 2R1B1FR (red/blue/far-red = 2:1:1), 2R1B1P (red/blue/purple = 2:1:1), 4R2B1G (red/blue/green = 4:2:1), 2R1B1G (red/blue/green = 2:1:1), and 2R1B (red/blue = 2:1). The results demonstrated distinct spectral regulation of seedling development: compared to the white light (CK), the 2R1B1FR (far-red light supplementation) treatment progressively stimulated stem elongation, increasing plant height and stem diameter by 81.6% and 25.9%, respectively, at day 21, but resulted in a more slender stem architecture. The 2R1B1G (balanced green light) treatment consistently promoted balanced growth, culminating in the highest seedling vigor index at the final stage. The 2R1B1P (purple light supplementation) treatment exhibited a strong promotive effect on root development, which became most pronounced at day 21 (126% increase in root dry weight), while concurrently enhancing soluble sugar content and reducing oxidative stress. Conversely, the 2R1B1Y (yellow light supplementation) treatment increased MDA content by 70% and led to a reduction in chlorophyll accumulation, while 2R1B (basic red–blue) resulted in lower biomass accumulation compared to the superior spectral treatments. The 4R2B1G (low green ratio) treatment showed context-dependent outcomes. This study elucidates how targeted spectral compositions, particularly involving far-red and green light, can optimize pepper seedling quality by modulating photomorphogenesis, carbon allocation, and stress physiology. The findings provide a mechanistic basis for designing efficient LED lighting protocols in controlled-environment agriculture to enhance pepper nursery production. Full article

Postharvest studies on Cerrado fruits remain scarce, and the use of LED light during storage is a recent and promising strategy. Cagaita (Eugenia dysenterica DC.), a native Cerrado fruit with high nutritional and economic value, is also highly perishable, which limits its marketability. This study evaluated the postharvest quality of cagaita fruits stored under LED light of different wavelengths. Fruits were exposed to red, green, blue, or white LEDs, or kept in the dark (control), under continuous illumination (24 h per day) for 5 days at room temperature (25.7 ± 2 °C). Green LED light significantly (p < 0.05) increased lightness, chroma, vitamin C, and antioxidant activity (DPPH assay), while maintaining a more stable pH compared with the control and, in some cases, other LED treatments. Overall, green LED was the most effective treatment for preserving the physicochemical and bioactive quality of cagaita fruits during storage. These findings provide evidence that LED light can help extend shelf life and enhance the market potential of this native Cerrado fruit. Full article

The development of a straightforward strategy for preparing organic fluorescent materials, fine-tuning white-light emission, and subsequently constructing white light-emitting diodes (LEDs) is of great significance. Herein, we report on the modulation of white-light emission and the fabrication of white LEDs using polyhedral oligomeric silsesquioxane (POSS)-based fluorescent hybrid porous polymers (HPPs) through simple physical blending. Two HPPs, namely HPP-1 and HPP-2, which emit blue and red light, respectively, were synthesized via the efficient Heck reactions of octavinylsilsesquioxane with 4,4′-dibromobiphenyl and 1,3,6,8-tetrabromopyrene. By physically doping of HPP-1 and HPP-2 in variable ratios in solvent suspensions, it was discovered that white-light emission is significantly influenced by the concentrations of the materials and the excitation wavelength. Similar findings were also observed in the solid-state physical doping. An ideal white light emission with a CIE coordinate of (0.33, 0.33) can be achieved when excited at 380 nm with a mass ratio of HPP-1 to HPP-2 of 1:2. Finally, the two HPPs were dispersed in polysiloxane matrices, and a white LED with a CIE coordinate of (0.42, 0.36) was obtained. The LED exhibited a color rendering index of up to 90 and a correlated color temperature of 2858 K, realizing warm white light emission. This simple and convenient white-light regulation strategy holds great promise for application in the development of novel white LEDs based on organic fluorescent porous materials. Full article

This study investigated how different spectral ranges of LED light affect the synthesis of photosynthetic pigments and antioxidant systems in Thymus mastichina L., focusing on two ecotypes with distinct chemotypes: linalool and eucalyptol. The ecotypes were exposed to white, red, blue, red-blue (70:30), white-blue, or white-red light for 30 days under a 16/8 h light/dark cycle (115 μmol/m²s). Photosynthetic pigment content, lipid oxidative damage, antioxidant capacities, and both enzymatic (SOD, CAT) and non-enzymatic (tocopherols and polyphenols) antioxidant systems were assessed. For the linalool chemotype, red-blue light significantly increased carotenoid content, antioxidant capacity, and catalase activity, while elevating levels of plastochromanol-8 and phenolic compounds such as salvianolic acid B, rosmarinic acid, and 6-OH-apigenin-7-hexoside, thereby reducing oxidative stress. In contrast, for the eucalyptol chemotype, pure red light produced the most significant enhancements in carotenoid synthesis and antioxidant defenses, substantial increases in key compounds such as salvianic, neochlorogenic, rosmarinic, and lithospermic acids, and salvianolic acids E and B, and higher levels of plastochromanol-8. Additionally, both SOD and CAT activities increased, providing greater protection against lipid oxidation. These findings highlight the importance of customizing light treatments not only based on plant species but also according to chemotype to obtain optimal biochemical and physiological outcomes. Full article

Eucomis autumnalis is a bulbous ornamental species with ethnobotanical relevance. In vitro cultures offer a sustainable tool for biomass propagation and metabolite production. This study investigates the effects of nine LED light spectra: red (R), blue (B), red–blue (RB), RB with green (RBG), yellow (RBY), far-red (RBfR), ultraviolet (RBUV), white (WLED), and fluorescent light (Fl, control), on the morphogenesis, polyphenol production, and antioxidant potential of E. autumnalis shoot cultures. Cultures were maintained on MS medium with 5 µM BA and 0.5 µM NAA. HPLC-DAD analysis identified 11 phenolic acids and 4 flavonoids, including eucomic acid, characteristic of the genus. Light quality impacted compound-specific accumulation and antioxidant activity, with responses varying among compounds and treatments. R and B light increased catechin, gentisic acid and hesperidin (289, 195, 245 mg/100 g DW), while UV suppressed flavonoids by ca. 2-fold for catechin and flavanones compared to other lights. RBG and RBfR induced the highest eucomic acid accumulation (424 mg/100 g DW), ferulic acid and epicatechin, correlating strongly with ABTS•+ activity (18–19% higher than other lights; r > 0.6–0.8). These findings highlight LED spectral modulation as a tool to enhance the phytochemical quality of E. autumnalis in vitro and provide a foundation for future biotechnological applications. Full article

The visual performance and photobiological effects of white LED systems based on spectral compensation are discussed, specifically focusing on the total optical power, the ratio of scotopic vision luminous flux to photopic vision luminous flux (S/P), the blue light hazard (BLH), and the circadian action factor (CAF). Theoretical models are established by integrating the spectral power distribution (SPD) with spectral sensitivity functions associated with the human visual system, and meanwhile, the impacts of LEDs’ electro-thermal characteristics on the mixed spectral structure and optical properties are analyzed. As experimental results demonstrate, an excellent agreement is shown between the calculated and measured values of the total optical power, S/P, BLH, and CAF, in terms of both values and variation trends. These proposed models are expected to serve as effective tools for understanding the visual perception and non-visual biological effects in specific illumination environments. Moreover, they can offer valuable reference frameworks for the development of lighting solutions that are more human-centered and health-oriented. Full article

Primula veris L. (cowslip) is a medicinal plant traditionally used for respiratory ailments, with its therapeutic properties attributed to triterpene saponins and phenolic glycosides found in the roots and the aerial parts. The present study aimed to investigate the impact of different LED light spectra (red, blue, red:blue, and white fluorescent as a control) on P. veris’s relative growth rate, physiology, and secondary metabolite production to optimize its cultivation under controlled conditions. The results demonstrate that the light quality significantly influences P. veris’s growth characteristics, physiology, and secondary metabolite production. Red light promoted leaf expansion, while the red:blue LED combination enhanced the root fresh weight and concentration of total chlorophylls and carotenoids in primrose leaves in comparison to the white fluorescent and solitary red light, respectively. Red light significantly increased the accumulation of key secondary metabolites (primeverin, primulaverin, and primulic acids) in roots during the flowering phase compared with the white inflorescent. In addition, the concentration of phenolic compounds was strongly influenced, showing a decrease between the vegetative and the flowering stage of development. Finally, this study highlights the potential of tailored LED lighting to optimize P. veris cultivation, enhancing both biomass and the production of valuable bioactive compounds, taking into account the developmental stage of the plants. Full article

Coriander leaves are widely valued in cooking due to their rich nutrition and unique volatiles, and the flowers are also beneficial for oil extraction from seeds. With the growing interest in LED lights for controlled environments, research on coriander leaves has been reported, but studies on flowers are limited. We investigated the effects of various LED lights, including white (W), red (R), blue (B), and green (G) lights, on flowering. Coriander plants under B light were twice as tall and flowered approximately 4 weeks earlier than those under other lights. However, plants under B light exhibited overgrowth, resulting in fewer flowers at a PAR of 100 µmol·m⁻²·s⁻¹. To reduce this shade avoidance effect, we tested various combinations of W and B light at a PAR of 120 µmol·m⁻²·s⁻¹. The 50:50 ratio of W and B light enhanced growth and accelerated flowering, resulting in twice as many flowers as plants under W light. Total volatile compound levels were higher under W light and highest under 50% W and 50% B lights. Key volatiles specific to coriander leaves, such as (E)-2-decenal, 2-undecenal, and 2-dodecenal, were high under G light at 100 µmol·m⁻²·s⁻¹ of PAR. These findings provide valuable insights into the effects of light on flower development. Full article

Biological swarms communicate through decentralized, adaptive behaviors shaped by local interactions, selective attention, and symbolic signaling. These principles of animal communication enable robust coordination without centralized control or persistent connectivity. This work presents a proof of concept that identifies, evaluates, and translates biological communication strategies into a generative visual language for unmanned aerial vehicle (UAV) swarm agents operating in radio-frequency (RF)-denied environments. Drawing from natural exemplars such as bee waggle dancing, white-tailed deer flagging, and peacock feather displays, we construct a configuration space that encodes visual messages through trajectories and LED patterns. A large language model (LLM), preconditioned using retrieval-augmented generation (RAG), serves as a generative translation layer that interprets perception data and produces symbolic UAV responses. Five test cases evaluate the system’s ability to preserve and adapt signal meaning through within-modality fidelity (maintaining symbolic structure in the same modality) and cross-modal translation (transferring meaning across motion and light). Covariance and eigenvalue-decomposition analysis demonstrate that this bio-agentic approach supports clear, expressive, and decentralized communication, with motion-based signaling achieving near-perfect clarity and expressiveness (0.992, 1.000), while LED-only and multi-signal cases showed partial success, maintaining high expressiveness (~1.000) but with much lower clarity (≤0.298). Full article

The rational design of artificial lighting systems in pig housing can enhance animal welfare, thereby boosting gilt health and reproductive performance while improving economic metrics for swine farms. To identify the optimal light environments for gilts under artificial illumination, we conducted self-selection-based photic preference testing, ultimately providing actionable insights for welfare-centric precision lighting protocols in modern pig production. In this study, a dynamic multi-chromatic self-selection system was developed, integrating programmable RGBW-LED arrays for spectral control, inter-compartment access channels for autonomous gilt movement, and real-time image recognition technology to investigate light color preferences. Twenty-four gilts (nulliparous female pigs) were housed for five weeks in pens with white, yellow, green, blue, or red light (100 lux), and they were given free access to all of the chromatic zones through inter-compartment channels. A YOLOv8n-based deep learning framework was used to quantify their spatiotemporal distribution, activity levels, and eating behavior. The key findings were the following: (1) a significant preference for green light environments (21.29 ± 3.77% distribution proportion) (p < 0.05), peaking at 6:00–13:00 and 18:00–20:00; (2) the average activity was the highest in a white light environment (25.49 ± 0.77%), significantly exceeding yellow (22.69 ± 0.63%) and green light (21.55 ± 0.61%) (p < 0.05); and (3) the daily feed consumption under green light was the lowest, significantly lower than that under white, blue, and red light (p < 0.05). The findings from this study offer insights into the light environment preferences of gilts, which could improve animal welfare. Full article