Search Results (228)

Cyanobacteria are a prolific source of bioactive metabolites with expanding applications in sustainable agriculture and biotechnology. This work explores, for the first time in thermotolerant Colombian isolates, the impact of light spectrum, photoperiod, and irradiance on the co-production of exopolysaccharides (EPS) and indole-3-acetic acid (IAA). Six strains from hot-spring environments were screened under varying blue:red (B:R) LED ratios and full-spectrum illumination. Hapalosiphon sp. UFPS_002 outperformed all others, reaching ~290 mg L⁻¹ EPS and 28 µg mL⁻¹ IAA in the initial screen. Response-surface methodology was then used to optimize light intensity and photoperiod. EPS peaked at 281.4 mg L⁻¹ under a B:R ratio of 1:5 LED, 85 µmol m⁻² s⁻¹, and a 14.5 h light cycle, whereas IAA was maximized at 34.4 µg mL⁻¹ under cool-white LEDs at a similar irradiance. The quadratic models exhibited excellent predictive power (R² > 0.98) and a non-significant lack of fit, confirming the light regime as the dominant driver of metabolite yield. These results demonstrate that precise photonic tuning can selectively steer carbon flux toward either EPS or IAA, providing an energy-efficient strategy to upscale thermotolerant cyanobacteria for climate-resilient biofertilizers, bioplastics precursors, and other high-value bioproducts. Full article

To ensure the year-round efficient production of high-quality cherry tomatoes, this study evaluated how four cherry tomato cultivars can enhance yield and quality through optimized nutrient solution and supplementary lighting. Nutrient solutions (N1 and N2) were adjusted, with EC at 1.6 dS/m (N1: nitrogen 10.7 me/L, phosphorus 2.7 me/L, potassium 5.3 me/L) during flowering stage, and 2.4 dS/m (N1: nitrogen 16 me/L, phosphorus 4 me/L, potassium 8 me/L; N2: nitrogen 10.7 me/L, phosphorus 5.4 me/L, potassium 10.8 me/L) from fruit setting to harvest. N1 used standard adjustments, while N2 was optimized by adding solely with KCl and KH₂PO₄. Lighting treatments included L1 (natural light) and L2 (supplemental red/blue light). The application of N2 effectively decreased nitrate levels while it significantly enhanced the content of soluble sugars, flavor, and overall palatability, especially fruit coloring in cherry tomatoes, irrespective of supplementary lighting conditions. However, such optimization also increased sourness or altered the sugar–acid ratio. Supplementary lighting generally promoted the accumulation of soluble sugars, sweetness, and tomato flavor, although its effects varied markedly among different fruit clusters. The combination of optimized nutrient solutions and supplementary lighting exhibited synergistic effects, improving the content of soluble sugars, vitamin C, proteins, and flavor. N1 combined with L2 achieved the highest plant yield. Among the cultivars, ‘Linglong’ showed the greatest overall quality improvement, followed by ‘Baiyu’, ‘Miying’, and ‘Moka’. In conclusion, supplementary lighting can enhance the effect of nitrogen on yield and amplify the influence of phosphorus and potassium on fruit quality improvement in cherry tomatoes. The findings of this study may serve as a theoretical basis for the development of year-round production techniques for high-quality cherry tomatoes. Full article

Rana dybowskii, widely distributed and extensively farmed in northeast China, holds significant economic value, particularly for its fallopian tubes, which are used as a traditional Chinese medicinal tonic known as “Oviductus Ranae.” As the light spectrum is a cost-effective regulatory factor in aquaculture, understanding its effects on the tadpole stage of R. dybowskii is critical for optimizing cultivation practices. This study investigated the effects of five light colors (white, red, yellow, blue, and green) on steroid hormone levels and gut microbiota composition in R. dybowskii tadpoles. Steroid hormone levels were measured on days 15, 30, 45, and 60 using high-performance liquid chromatography (HPLC), while gut microbial communities were analyzed through high-throughput 16S rRNA sequencing. Results showed that the testosterone (T) level of frogs in green light (group G) peaked on day 60 (2.62 ± 3.70 ng/g). The estradiol (E2) level in blue light (group B) also peaked on day 60 (2.87 ± 0.71 ng/g). Importantly, sex ratio analysis revealed that the proportion of females was highest under blue light, reaching 61.11%. Meanwhile, the richness and diversity of the gut bacterial community of the tadpoles was highest under yellow light, followed by blue light. These data suggest that hormone levels fluctuated and the composition of the gut flora of R. dybowskii changed under different light colors. Our results advance R. dybowskii physiological knowledge and support aquaculture practices. Full article

See-through augmented reality glasses, such as HoloLens 2, are increasingly adopted in medical settings; however, their efficacy as medical display devices remains unclear, as current evaluation protocols are designed for traditional monitors. This study examined whether the established display-evaluation techniques apply to HoloLens 2 and whether it meets standards for primary and secondary medical displays. HoloLens 2 was assessed for overall image quality, luminance, grayscale consistency, and color uniformity. Five participants rated the TG18-OIQ pattern under ambient lighting conditions of 2.4 and 138.7 lx. Minimum and maximum luminance were measured using the TG18-LN12-03 and -18 patterns, targeting ≥ 300 cd/m² and a luminance ratio ≥ 250. Grayscale conformity to the standard grayscale display function allowed deviations of 10% for primary and 20% for secondary displays. Color uniformity was measured at five screen positions for red, green, and blue, with a chromaticity limit of 0.01 for primary displays. HoloLens 2 satisfied four of the ten primary and four of the seven secondary overall-quality criteria, achieving a maximum luminance of 2366 cd/m² and a luminance ratio of 1478.75. Grayscale uniformity was within tolerance for 10 of the 15 primary and 13 of the 15 secondary measurements, while 25 of the 30 color uniformity values exceeded the threshold. The adapted evaluation methods facilitate a systematic assessment of HoloLens 2 as a medical display. Owing to inadequate grayscale and color representation, the headset is unsuitable as a primary diagnostic display; for secondary use, requirements must be assessed based on specific application requirements. Full article

Aegopodium podagraria (A. podagraria) L. is a perennial herb valued for its medicinal properties but exhibits poor germination and inconsistent growth under conventional cultivation. To overcome these limitations and enhance its functional potential, this study investigated the effects of various LED light spectra on the plant’s physiological and antioxidant responses under controlled indoor conditions. Six light treatments were applied, consisting of different red (R) and blue (B) light ratios (R100, R80:B20, R60:B40, R40:B60, and B100), along with a white-light control. Red-dominant treatments, particularly R80:B20, not only improved germination traits but also significantly promoted shoot growth and biomass accumulation. In contrast, higher proportions of blue light generally inhibited germination performance and reduced growth-related parameters compared to the white-light control. Antioxidant activity was also modulated by light quality: R80:B20 induced the highest levels of total phenolics, ferric reducing antioxidant power, and vitamin C, whereas R40:B60 maximized flavonoid content and DPPH radical scavenging activity. These results suggest that optimizing the red-to-blue light ratio can effectively enhance both the cultivation performance and biofunctional quality of A. podagraria in controlled environments. Full article

To investigate whether blue-dominant spectra from end-of-day (EOD) lighting can regulate crop morphological and flowering responses, chrysanthemum (Chrysanthemum × morifolium; obligate short day), geranium (Pelargonium × hortorum; day neutral), calibrachoa (Calibrachoa × hybrida; facultative long day), and gerbera (Gerbera jamesonii; facultative short day) plants were grown under different light-emitting diode (LED) spectrum treatments from January to April 2020, in Guelph, Canada. The spectrum treatments were (1) no EOD lighting, (2) narrowband blue from LEDs (B), (3) a combination of narrowband blue, red, and far-red LEDs with a photon flux ratio of 47:3:1 (blue:red:far-red; BRFR). The B and BRFR treatments ran daily from 0.5 h to 4.5 h after dusk. Compared to the control without EOD lighting, chrysanthemum flower initiation was completely inhibited under BRFR. Flowering time was slightly delayed, but flower bud number increased under B. Side branch number, leaf area, and main stem length and diameter increased under B and BRFR. In the geranium B and BRFR did not affect flowering, but increased side branch number and length and diameter of the main stem. Both spectrum treatments promoted earlier flowering in the calibrachoa, but BRFR produced more flower buds. The calibrachoa aerial dry biomass and main stem length increased under B and BRFR. The gerbera leaf chlorophyll index and leaf thickness increased under BRFR. Both spectrum treatments increased the gerbera flower bud size, despite having little effect on flowering time. In all species, at least one of the LED treatments increased canopy size. Therefore, low levels of B or BRFR can be potentially used for EOD lighting to regulate the flowering and morphology of potted ornamentals. Full article

This study investigates the effect of monochromatic light on the body weight (BW), melatonin concentration and its receptors expression levels, intestinal health, and gut microorganisms of Yangzhou geese. Green light (GL) significantly increased BW, melatonin and its receptor expression levels, villus height (VH) and villus height/crypt depth (VH/CD) ratio, superoxide dismutase (SOD), catalase (CAT), and total antioxidant capacity (T-AOC) activities, as well as the abundance of Synergistota and Prevotellaceae_UCG-001, compared with white light (WL). Blue light (BL) significantly increased the mRNA expression of melatonin membrane receptor 1a (Mel1a) and nuclear receptor 1α (RORα), VH and VH/CD ratio, CAT activity, cecal microbes diversity, and decreased malondialdehyde (MDA) levels. Red light (RL) significantly decreased average daily feed intake, reduced the abundances of Synergistota and Prevotellaceae_UCG-001, and increased Mel1a and RORα mRNA expression levels, MDA content, and cecum microbial diversity. Moreover, melatonin levels were significantly higher in the GL and BL groups compared to RL. Furthermore, the mRNA expression levels of Claudin-10, Occludin, and occludens-1 (ZO-1) were significantly upregulated under GL or BL exposures compared to the WL group, whereas RL only enhanced the expression levels of ZO-1. Spearman’s correlation analysis revealed that the relative abundance of Prevotellaceae_UCG-001 exhibited positive correlations with BW, melatonin and its receptors expression, gut health, and antioxidant capacity. Overall, these findings suggested that GL exposure enhanced melatonin synthesis and its receptors expression, modulated intestinal homeostasis and microbial ecology, and ultimately increased goose BW. Full article

Plant factories offer a promising opportunity for fresh food production due to their minimal land requirements. Among the adjustable factors in the production system of plant factories, light serves as a critical element, significantly influencing both crop yield and quality. Cilantro, a prevalent culinary herb and a traditional flavoring agent, plays a crucial role in Taiwanese gastronomy. This research investigated cilantro plants grown under nine different light treatments with varying red to far-red ratios and green light percentages over a 49-day period. Results demonstrate that maximum fresh and dry biomass accumulation in both shoot and root tissues occurred under treatments with red to far-red ratios of approximately of 1.8 combined with medium green light intensity. Conversely, medium far-red ratios negatively affected lutein and carotenoid concentrations in foliar tissues. Carotenoid biosynthesis exhibited an inverse relationship with green light intensity, with lower green light percentages corresponding to significantly higher carotenoid concentrations. In terms of energy efficiency, a red to far-red ratio of approximately 1.8 yielded the highest energy yield (g kWh⁻¹) and photon yield (g mol⁻¹), indicating optimal energy conversion efficiency under this spectral composition. In conclusion, this study demonstrates that cilantro cultivation under R53G05B13FR29 spectral composition (53% red, 5% green, 13% blue, 29% far-red) with a 49-day production cycle maximizes biomass while optimizing energy utilization efficiency. Full article

Low-cost unmanned aerial vehicle (UAV) visible light remote sensing provides new opportunities for plant community monitoring, but its practical deployment in different ecosystems is still limited by the lack of standardized vegetation index (VI) optimization for multi-species coverage extraction. This study developed a universal method integrating four VIs—Excess Green Index (EXG), Visible Band Difference Vegetation Index (VDVI), Red-Green Ratio Index (RGRI), and Red-Green-Blue Vegetation Index (RGBVI)—to bridge UAV imagery with plant communities. By combining spectral separability analysis with machine learning (SVM), we established dynamic thresholds applicable to crops, trees, and shrubs, achieving cross-species compatibility without multispectral data. The results showed that all VIs achieved robust vegetation/non-vegetation discrimination (Kappa > 0.84), with VDVI being more suitable for distinguishing vegetation from non-vegetation. The overall classification accuracy for different vegetation types exceeded 92.68%, indicating that the accuracy is considerable. Crop coverage extraction showed a minimum segmentation error of 0.63, significantly lower than that of other vegetation types. These advances enable high-resolution vegetation monitoring, supporting biodiversity assessment and ecosystem service quantification. Our research findings track the impact of plant communities on the ecological environment and promote the application of UAVs in ecological restoration and precision agriculture. Full article

Light is crucial in controlled-environment agriculture (CEA), affecting germination, growth, and overall plant quality. Here, we explored the optimization of various LED light spectra on the germination traits such as germination percentage, mean germination time, germination index, vigor index, and early seedling growth of ‘Lollo Bionda’ lettuce seedlings in a plant factory. A completely randomized design was implemented, involving three replications. LED lamps with different spectral compositions—red (R, peak at 656 nm), red/blue (3:1 ratio, R:B, peak at 656 nm), blue (B, peak at 450 nm), and white (400–700 nm)—were utilized in this study. The combination of red and blue LED lights, along with monochromatic red and blue treatments, significantly enhanced germination traits and early seedling growth compared to white and ambient lighting. The combined spectrum resulted in the highest seedling emergence, the longest shoot and root lengths, and the highest fresh weight. These findings underscore the potential of the LED technology to improve germination efficiency and enhance seedling quality in CEA. Future studies should refine multispectral LED strategies by examining factors such as light intensity and photoperiod, while also elucidating the molecular pathways involved in light-driven germination and early development in lettuce. Full article

Light and nutrient availability are critical factors of plant growth and development, particularly at the early stages, where they significantly influence the establishment and survival of young seedlings. The morphological parameters and the biomass accumulation of soybean were measured in a hydroponic vertical farm in the first 14 days of seedling growth in two successive experiments under two types of lighting environments and at three nutrient concentration levels. The lighting conditions were set by two parallel variable-spectrum linear luminaires positioned above the lower and upper edges of the cultivation trays. In the first lighting environment, seedlings were exposed to a constant photosynthetic photon flux density (PPFD) with red and blue photon irradiance ratio (R/B) varying in broad range from the lower to the upper end of the cultivation trays. In the second environment, the spatial R/B distribution was uniform, and the PPFD varied between two maxima at the edges and a minimum in the middle of the trays. The R/B ratio within the 0.6–6 interval had little or no effect on plant development. We report the dependence of growth traits as a function of PPFD in the range of 30–290 µmol m⁻² s⁻¹ in full-strength, half-strength, and blank nutrient solutions. The light response for shoot height and the first internode length was mainly influenced by blue light. We observed a rapid decline in growth between 6–20 µmol m⁻² s⁻¹ blue photon irradiance. The shoot height and first internode length did not change significantly at higher blue light intensities. The lengths of the first internode and the root dry mass did depend on the nutrient solution strength. All other growth traits, including stem diameter, leaf size, shoot mass, root mass, and SPAD readings, showed a linear correlation with PPFD and electrical conductivity. The leaf mass and root mass ratios indicated that soybeans adopt a nutrient search strategy by giving preference for root growth while increasing shoot height at the expense of the shoot diameter in conditions of low nutrient availability and low light intensity. The functional relationships determined in the experiments provide valuable inputs to plant growth models. The methodology we employed could also be used to study other plant species and to investigate the interactive effects of specific nutrients and lighting conditions. Full article

Strawberry fruits accumulate nutritionally critical anthocyanins and phytochemicals through light=quality-dependent metabolic regulation. This review systematically examines spectral modulation strategies for enhancing anthocyanin biosynthesis and fruit quality parameters. We demonstrate that dual red (660 nm) and blue (450 nm) irradiation optimally activates the flavonoid pathway, co-upregulating structural genes (CHS, F3H, DFR, ANS) and regulatory factors (FaMYB10, FaHY5). Mechanistic analyses reveal that blue light preferentially induces upstream phenylpropanoid enzymes (PAL, C4H, CHI), while red light enhances proanthocyanidin production through differential induction of LAR and ANR. Strategic supplementation with UV-C (254 nm, 1–2 kJ/m²/d) and far-red (730 nm, 15 μmol·m⁻²·s⁻¹) improves anthocyanin spatial distribution via stress-mediated epidermal accumulation. Spectral optimization further coordinates flavor development by (1) balancing sucrose–hexose ratios through FaSPS1 modulation, (2) reducing organic acid content via FaMYB44.2 suppression, and (3) amplifying volatile esters (e.g., methyl anthranilate) through SAAT induction. Postharvest UV-C treatment (4 kJ/m²) extends shelf life by 30–35% through microbial inhibition and antioxidant system activation. Practical implementation frameworks propose phase-specific LED protocols related to vegetative growth (R:B = 3:1), flowering (R:B = 1:1), and maturation (R:B = 4:1) stages integrated with environmental sensors in controlled agriculture systems. These findings establish an actionable paradigm for photonic crop management, synergizing molecular precision with commercial horticultural operations to achieve sustainable yield enhancement (projected 22–28% increase) and nutraceutical enrichment. Full article

This study aimed to investigate the effects of different light qualities on the morphological development, photosynthetic characteristics, stomatal structure, and yield of potato, providing theoretical and practical guidance for optimizing light environments in controlled agricultural systems and enhancing the efficient production of potato microtubers. Six light qualities—white, red, blue, green, far-red, and ultraviolet—were applied to systematically evaluate their effects. The results showed that light quality significantly influenced plant morphological traits and physiological metabolism. Red and blue light demonstrated the most pronounced promotive effects. Under red light, plant height and stem diameter increased by 57.47% and 31.10%, respectively, compared to white light, while single tuber weight increased by 20.09%, despite a 14.96% reduction in tuber number per plant. Blue light significantly enhanced chlorophyll content (by 20.35%) and stomatal density (adaxial stomata increased by 28.85%), leading to a 38.98% increase in tuber number, a 51.79% increase in single tuber weight, and a remarkable 110.37% improvement in total yield per plant, compared to white light. In contrast, green light moderately promoted photosynthesis in lower leaves, but reduced the total yield by 39.90%. Far-red (740 nm) and ultraviolet light (390 nm) severely inhibited plant growth and failed to induce tuber formation. Correlation analysis revealed a highly significant positive relationship between chlorophyll content, net photosynthetic rate, stomatal density, and yield per plant (r = 0.96, p < 0.01). This study systematically evaluated the independent effects of single light quality on potato growth and production for the first time, clarifying the regulatory advantages of red and blue light, and providing important theoretical insights for optimizing the light environment with red and blue light to improve potato microtuber yield. Furthermore, this study provides critical data to support future research on the dynamic optimization of light quality ratio. Full article

Blue and supplemental far-red light were observed to affect in vitro shoot growth with Cannabis sativa (‘BaOx’ and ‘Cherry 1’) in RV750 vessels. A modified “hedging” and fed-batch system for multiple harvests using Oasis^® foam and 120 mL DKW medium was used. Fifteen nodal and/or apical tips were planted and placed into PAR light treatments providing various red to blue ratios (polychromatic white 9:1 RB and dichromatic 2–15: 1 RB, with and without 5% far-red light). Treatments had similar light intensities (190–240 µmol · m⁻² · s⁻¹ PPFD) for a 16 h photoperiod. Shoot tips were harvested in vitro on five successive two-week cycles, with 15 mL of DKW media supplemented to each vessel following harvest. Shoot numbers, length, and fresh and dry mass were recorded at each cycle harvest. Five randomly selected shoot tips per vessel were rooted ex vitro on greenhouse mist bench for 16 days. Over multiple cycles, 5% far-red increased shoot numbers and length in both genotypes tested, regardless of polychromatic or dichromatic source. Shoots harvested per vessel increased from 15 to 28 in three cycles (6 weeks), but increased from 15 to 18 without far-red treatment. Shoot length in far-red-treated plants increased from 19 to 25 mm during cycles 1–3. Plants without far-red treatment were approximately 15 mm during the first three cycles. By cycle 5, both far-red- and non-far-red-treated plants decreased to 10 mm. Dry mass was greatest in cycle 1 for both genotypes (‘Cherry 1’ was 6 mg and ‘BaOx’ was 7 mg) under the highest amount of blue light, but 2 mg under the lowest amount of blue light. Dry mass decreased by 50% in cycle 3, to 4 mg, where it remained for the duration of the experiment. Sixty eight percent of shoots rooted ex vitro on the mist bench, regardless of any prior in vitro treatment. Full article

Food fraud is a matter of great interest, particularly when organic productions are involved. Therefore, policymakers and institutions are asked to introduce new effective official control methods, not only based on documentary compliance to EU regulations. Lately, an integrated approach based on the use of isotopic, chemical and biological data treated by chemometrics has been suggested to authenticate organic products. The present research aims to validate the beforementioned integrated approach for the reliable classification of organically and conventionally grown fennel productions obtained by applying different treatments at diverse percentages of mineral fertilizers. Moreover, to the best of our knowledge, for the first time, an N-fixing plant (alfalfa), as an agroecological service crop in intercropping fennel, was introduced. Physicochemical parameters (fresh weight, total soluble solids, total acidity, consistency, Commission Internationale de l’Eclairage (CIE) lightness (L*), green-red (a*), blue-yellow (b*) color components), total phenolic content, in vitro antioxidant activity, total and inorganic N, and stable isotope ratios (¹⁵N/¹⁴N, ¹³C/¹²C, and ³⁴S/³²S) analyses were performed over a two-year field trial and further multivariate discriminant analysis was performed. The physicochemical parameters were not affected by the differential growing practice while antioxidant activity showed higher values in the organic treatments. The conventional treatments increased the NO₃⁻ values over 440% compared to the organic ones and the lowest values were found when alfalfa was used for intercropping. δ(¹⁵N) of fennel, δ(³⁴S) of fennel and δ(¹⁵N) of leaves showed great discriminatory potential, with respect to the applied agronomic practice. However, these parameters alone were not sufficient as biomarkers for differentiating cultivation methods. Instead, the proposed innovative tool demonstrated that only a comprehensive multivariate approach was able to achieve a correct classification of grouped cases. Furthermore, the discrimination between organic and conventional horticultural products showed feasible results, even when N-fixing plants were incorporated in organic practice, thus avoiding misinterpretations solely based on the isotopic N fingerprint. These promising findings highlight the potential of this method and suggest that further research should extend its application to other horticultural crops to confirm and expand upon the current results. Full article