Search Results (55)

In controlled environment agriculture (CEA), supplementary lighting, particularly light-emitting diode (LED) technology, is essential for optimizing plant growth and development. Among the spectral components, blue light (400–500 nm) plays an important role in affecting plant morphogenesis, photosynthesis, and key physiological processes. However, species-specific guidelines for optimizing blue light parameters such as intensity, duration, and spectral ratios remain insufficiently developed. Furthermore, plant spectral requirements shift across developmental stages, highlighting distinct blue light management strategies for each phase. This review synthesizes existing knowledge on the impacts of blue light on morphological adaptation, photosynthetic efficiency, flowering, and secondary metabolism, with an emphasis on differential responses across diverse plant species. We emphasize the need for growth-stage-specific lighting protocols and scalable strategies applicable to commercial CEA systems. Interdisciplinary collaboration, integrating molecular biology, genomics, and horticultural engineering, is necessary to enhance understanding of blue light-driven regulatory networks, optimize photoreceptor responses, and facilitate systematic validation of adaptive lighting approaches, ultimately advancing sustainable horticulture and next-generation CEA innovations. Full article

Light spectral composition critically regulates plant morphogenesis and molecular adaptation in controlled environments. This study investigated the synergistic effects of three light spectra, red-blue (RB, 7:3), red-blue-green (RGB, 7:3:1), and red-blue-far-red (RBFR, 7:3:1), on multiplication, morphogenesis, physiological traits, and transcriptomic dynamics in tissue-cultured strawberry (Fragaria × ananassa cv. ‘Benihoppe’). After 28 days of cultivation under controlled conditions (25 °C/22 °C day/night, 50 μmol·m⁻²·s⁻¹ PPFD), RBFR and RGB treatments significantly enhanced shoot multiplication (38.8% and 24.2%, respectively), plant height, and callus biomass compared to RB light. RGB elevated chlorophyll a and b by 1.8- and 1.6-fold, respectively, while RBFR increased soluble protein content by 16%. Transcriptome analysis identified 144 and 376 differentially expressed genes (DEGs) under RGB and RBFR, respectively, enriched in pathways linked to circadian rhythm, auxin transport, and photosynthesis. Far-red light upregulated light signaling and photomorphogenesis genes, whereas green light enhanced chlorophyll biosynthesis while suppressing stress-responsive genes. These findings elucidate the spectral-specific regulatory mechanisms underlying strawberry micropropagation and provide a framework for optimizing multispectral LED systems in controlled-environment horticulture. Full article

Okra (Abelmoschus esculentus) is a tropical vegetable with high nutritional and economic value. Rich in fiber, vitamins (C, K, and B9), and minerals (magnesium, potassium, calcium, and iron), it contributes to food security in many tropical regions. Global production is estimated at 11.5 million tons in 2023, 62% of which will come from India. Nigeria, Mali, Sudan, Pakistan, and Côte d’Ivoire are also among the major producers. Given its economic importance, optimizing its growth through controlled methods such as greenhouse cultivation and light-emitting diode (LED) lighting is a strategic challenge. Energy-efficient LED horticultural lighting offers promising prospects, but each plant variety reacts differently depending on the light spectrum, intensity, and duration of exposure (photoperiod). This study evaluated the effects of different LED spectra on okra’s flowering after 30 days of growth using B (blue, 445 nm) and R (red, 660 nm) LED lights and red-blue alternating in a three-day cycle (R3B3) by alternating the photoperiod from 14 to 10 h. Outdoor and greenhouse conditions served as controls. The results show that the R3B3 treatment improves germination in terms of both speed and percentage. However, plant growth (height, stem diameter, and leaf area) remains higher in the control group. R3B3 and red light stimulate leaf and node development. Flowering occurs earlier in the control group (51 days) and later under LED, particularly blue (73 days). Fruit diameter after petal fall was also larger in the control group. These results confirm the sensitivity of okra to photoperiod and light quality, and highlight the potential of spectral and photoperiod manipulation to regulate flowering in controlled-environment agriculture. 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 paper examines the essential role of artificial lighting in protected agriculture, a crucial sector in addressing the increasing global food demand and the challenges posed by climate change. It explores how advanced lighting technologies, particularly LED systems, have revolutionized productivity and sustainability in greenhouses and indoor or urban farming systems. These technologies enable precise control over key factors influencing crop growth, optimizing both yield and resource efficiency. The methodology was based on a bibliometric analysis developed in four phases: collection of information in the scientific database Scopus, filtering and selection of relevant documents, quantitative and qualitative analysis of trends, and visualization of the results using tools such as VOSviewer. The study included scientific publications between 1974 and 2024, focusing on keywords related to greenhouse lighting technologies and protected agriculture systems. Key findings identified a significant increase in research over the last two decades, with countries such as the United States, Canada, the Netherlands, and China leading the way in scientific output. The main trends in artificial lighting for protected agriculture include the use of specific light spectra (particularly red and blue) to optimize photosynthesis and morphogenesis, as well as the integration of LED systems with digital sensors and controllers for enhanced precision. However, in developing countries such as Colombia, the adoption of these technologies remains in its early stages, presenting significant opportunities for implementation and expansion. Additionally, this bibliometric analysis provides a robust foundation for identifying key areas for improvement and guiding future research toward more sustainable and efficient agricultural practices. Full article

This study presents a pioneering investigation into the use of Light Emitting Diodes (LEDs) for in vitro rooting of ‘Marubakaido’ apple tree rootstocks, marking the first report of this approach in the literature. The research evaluates the effects of four distinct light sources: blue LED (450 nm), red LED (660 nm), a combination of red and blue LEDs, and traditional fluorescent lamps as a control. Mini-cuttings were inoculated in Murashige and Skoog (MS) medium with reduced nutrient concentrations, supplemented with indoleacetic acid (IAA) and sucrose. The explants were incubated under controlled conditions for 30 days, enabling a comprehensive assessment of the impact of different light sources on various growth metrics. The results revealed that blue LEDs significantly enhanced dry mass accumulation in seedlings compared to both red LEDs and fluorescent lamps, demonstrating their superior effectiveness in promoting plant growth. The use of LEDs not only improves seedling development but also offers economic advantages over fluorescent lamps. LEDs are characterized by high luminous efficiency, low energy consumption, and a long operational lifespan, which collectively reduce costs in plant production systems. This research advances the understanding of light-mediated effects on plant tissue culture and highlights the potential of combining blue and red LEDs as a viable alternative to fluorescent lighting. These findings could revolutionize practices in horticulture and plant propagation, providing a more efficient and sustainable approach to in vitro cultivation. Full article

Lighting is a fundamental driver of plant productivity in controlled-environment agriculture (CEA), directly affecting physiological processes, resource efficiency, and sustainability. This study evaluates the effects of distinct lighting systems, industrial Light-Emitting Diodes (iLEDs), horticultural LEDs (hLEDs), high-pressure sodium (HPS) lamps, and controls (no supplemental light), each providing unique light spectra, on cucumber (Cucumis sativus L.) growth, physiology, and environmental impact under a controlled light intensity of 250 µmol m⁻² s⁻¹ in a commercial CEA setup. The results indicated that iLEDs enhance intrinsic water use efficiency (35.65 µmol CO₂/mol H₂O) and reduce transpiration, reflecting superior physiological resource use. Electrophysiological measurements indicated significantly more stable stress responses in plants subjected to iLEDs and hLEDs as compared to HPS and control treatments, indicating the effectiveness of LED light spectra in mitigating stress-related physiological impacts. Furthermore, compact growth and shorter stem internodes were observed under iLEDs as well as hLEDs, highlighting the spectral effects on photomorphogenesis, likely caused by a balanced light spectrum. HPS lighting achieved the highest yield (42.86 kg m⁻²) but at a significant environmental cost, with 342.65 kg CO₂e m⁻² emissions compared to 204.29 kg CO₂e m⁻² for iLEDs, with competitive yield of 38.84 kg m⁻². Economic analysis revealed that iLEDs also offered the most cost-effective solution due to lower energy consumption and extended lifespan. This study focused on the interaction between light spectra, photosynthetic performance, stress resilience, and resource efficiency, advancing sustainable strategies for energy-efficient food production in CEA systems. Full article

This study conducted a comparative analysis on the effects of smart automatic and semi-automatic irrigation methods on the physiological characteristics and growth of Prunus × yedoensis Matsum. seedlings. The smart automatic irrigation system, which activates irrigation when the soil moisture drops below 15%, demonstrated superior characteristics in sap-wood area and bark ratio, as well as excellent water management efficiency, compared to the semi-automatic irrigation method, which involves watering (2.0 L) for 10 min at 60 min intervals starting at 8 AM every day. The analysis of soil moisture content changes under varying weather conditions and irrigation methods showed that smart automatic irrigation effectively maintained optimal moisture levels. Moreover, sap flow in the smart automatic irrigation treatment was more efficiently regulated in response to seasonal variations, showing a strong correlation with climatic factors such as temperature and solar radiation. In contrast, the semi-automatic irrigation treatment led to excessive sap flow during the summer due to a fixed watering schedule, resulting in unnecessary water supply. Analysis of photosynthesis parameters and chlorophyll fluorescence also revealed that smart automatic irrigation achieved higher values in light compensation and saturation points, maximizing photosynthetic efficiency. These findings suggest that the smart automatic irrigation system can enhance plant growth and water use efficiency, contributing to sustainable water management strategies. This research provides critical foundational data for developing efficient agricultural and horticultural irrigation management strategies in response to future climate change. Full article

The tomato plant is one of the most important vegetable crops, with a global production of around 188 million tones. The greatest losses in quantity and quality occur during storage, transport, and sale. The aim of the study was to determine the effect of irradiation on the quality and storability of the tomato ‘Tomimaru Muchoo’. Fruit harvested at the turning ripening stage were illuminated for the first two weeks at 15 °C with four visible LED light spectra, with different percentages of blue, green, and red light (BGR). The illumination times were 4 and 8 h per day (hpd). After illumination, the tomatoes were stored at 20 °C in the dark for 4 weeks. Immediately after 14 d of illumination, all tomatoes were fully ripe, although they showed varying red color intensity. In addition, all fruit retained very good quality and freshness. During further storage at 20 °C, there was a gradual decrease in tomato quality. However, LED lighting helped delay softening, reduce rotting, and thus maintain better tomato quality. Longer daily irradiation (8 h) delayed tomato senescence to a greater extent than shorter irradiation (4 hpd). Comparing the spectra, the greatest reduction in softening and rotting occurred in tomatoes illuminated with the spectrum containing the highest amount of blue light (56%). These tomatoes also maintained the lowest color index (a*/b*) throughout storage at 20 °C, which was especially evident in tomatoes that had been illuminated for 8 hpd. The light treatment influenced the maintenance of higher levels of ascorbic acid and antioxidant activity in tomatoes. However, irradiation did not increase the polyphenol content of tomatoes or reduce the lycopene levels in the fruit. Overall, the results showed that LED irradiation during storage improves storability and affects the health-promoting components of tomato fruit. It is a promising tool for reducing losses of horticultural produce. Full article

Urban agriculture has emerged as a crucial strategy to address food security and sustainability challenges, particularly in densely populated areas. This study focused on enhancing leafy greens’ production, specifically lettuce (Lactuca sativa L.) and arugula or rocket (Eruca sativa L.), using Nutrient Film Technique (NFT) systems and automation in container-based vertical farming. The study utilized a 20-foot shipping container retrofitted to create a thermally insulated and automated growth environment equipped with energy-efficient LED lighting and precise climate control systems. The results demonstrated significant improvements in crop yields, with the NFT systems achieving productivity up to 11 times higher than traditional methods in protected horticulture. These systems enabled continuous cultivation cycles, responding to the high market demand for fresh local produce. Moreover, the integration of low-cost sensors and automation technologies, each costing under USD 300, ensured that the environmental conditions were consistently optimal, highlighting this approach’s economic feasibility and scalability. This low-cost framework aligns with industry standards for affordable technology, making it accessible for small- to medium-sized urban agriculture enterprises. This study underscores the potential of vertical farming as a sustainable solution for urban food production. It provides a model that can be replicated and scaled to meet the growing demand for healthy, locally grown vegetables. Full article

Evaluating different concentrations of oxygen on lettuce physiology, growth, and biochemical assays is pivotal for optimizing the nutrient film technique (NFT), boosting yields, and enhancing resource efficiency in sustainable greenhouse cultivation. Two lettuce varieties Lactuca sativa var. Lolo Bionta (Lugano) and Lolo Rosa (Carmesi), were grown using NFT in a greenhouse for two consecutive years during the months of December and January. A comparative methodology was adopted under a randomized complete block design (RCBD) to study plant growth under three different oxygen concentration levels: natural oxygen concentrations (NOC); elevated oxygen concentrations (EOC); and elevated oxygen concentrations under LED light (380–840 nm) (LED + EOC). The plants were exposed to EOC levels of 8.1–8.7 mg L⁻¹ in December and 8.7–9.0 mg L⁻¹ in January. Under LED + EOC conditions, the levels were 8.2–8.3 mg L⁻¹ in December and 8.8–9.0 mg L⁻¹ in January. The NOC levels were 6.8–7.1 mg L⁻¹ in December and 7.2–7.8 mg L⁻¹ in January for Lugano and Carmesi, respectively. The applied light intensity, measured as photosynthetic photon flux density (PPFD), ranged from 463 to 495 µmol m⁻² s⁻¹ for the Lugano and from 465 to 490 µmol m⁻² s⁻¹ for the Carmesi. The dissolved oxygen concentration and LED light exposure under greenhouse conditions had significant effects (p < 0.05) on the plant growth parameters. The biochemical and physiological attributes, including transpiration rate, stomatal conductance, nitrate, chlorophyll, sugar contents, net photosynthesis, and respiration rates, varied significantly across different oxygen concentrations. Data were analyzed using a two-way ANOVA with post hoc Tukey’s HSD tests for significance (p < 0.05) using IBM SPSS Statistics (version 29.0.2.0). Both EOC and LED + EOC treatments significantly improved growth attributes compared to NOC in Lugano, with increases in plant height (16.04%, 0.85%), fresh mass (110.91%, 29.55%), root length (27.35%, 29.55%), and root mass (77.69%, 34.77%). For Carmesi, similar trends were observed with increases in plant height (5.64%, 13.27%), fresh mass (10.45%, 21.57%), root length (37.14%, 47.33%), and root mass (20.70%, 41.72%) under EOC and LED + EOC. In the intertreatment analysis, the effect of LED + EOC was more pronounced compared to EOC. In view of the intertreatment response, Lolo Bionta (Lugano) appeared to have a high overall horticultural performance (growth and yield in both EOC and LED + EOC compared to Lolo Rosa (Carmesi). The practical significance of these results lies in their potential to inform strategies for optimizing greenhouse environments, particularly through the manipulation of oxygen levels and light exposure. The significant increases in growth metrics, especially under the LED + EOC conditions, suggest that targeted environmental adjustments can lead to substantial improvements in lettuce yield and quality. The findings also contribute to the advancement of sustainable agricultural technologies aiming to enhance food security and sustainability. Full article

There are many possible LED lighting applications where separate regulation of the LED current (luminous flux) of individual LED strings would be desirable—specialized variable correlated color temperature lights for ambient lighting, decorative lighting, surgical lights, horticultural lights, etc. Separate regulation of the current or light flux of individual LED strings is associated with a known problem: the necessity of using a controllable LED driver for each string, which increases the total component count, overall system complexity and costs. One of the possible solutions—a current source mode single-inductor multiple-output LED driver—was discussed in previous different papers. However, the practical implementation of this solution was not discussed in detail. This article aims to correct this omission. Full article

Indoor agriculture is emerging as a promising approach for increasing the efficiency and sustainability of agri-food production processes. It is currently evolving from a small-scale horticultural practice to a large-scale industry as a response to the increasing demand. This led to the appearance of plant factories where agri-food production is automated and continuous and the plant environment is fully controlled. While plant factories improve the productivity and sustainability of the process, they suffer from high energy consumption and the difficulty of providing the ideal environment for plants. As a small step to address these limitations, in this article we propose to use internet of things (IoT) technologies and automatic control algorithms to construct an energy-efficient remote control architecture for grow lights monitoring in indoor farming. The proposed architecture consists of using a master–slave device configuration in which the slave devices are used to control the local light conditions in growth chambers while the master device is used to monitor the plant factory through wireless communication with the slave devices. The devices all together make a 6LoWPAN network in which the RPL protocol is used to manage data transfer. This allows for the precise and centralized control of the growth conditions and the real-time monitoring of plants. The proposed control architecture can be associated with a decision support system to improve yields and quality at low costs. The developed method is evaluated in emulation software (Contiki-NG v4.7),its scalability to the case of large-scale production facilities is tested, and the obtained results are presented and discussed. The proposed approach is promising in dealing with control, cost, and scalability issues and can contribute to making smart indoor agriculture more effective and sustainable. Full article

Full-spectrum light-emitting diodes (LEDs) mainly comprising 460-nm + 595-nm light are becoming a mainstay in the horticulture industry, and recent studies indicate that plant productivity under white LEDs is higher than combined blue and red LED lighting. Different light properties (wavelength and bandwidth) in full-spectrum light, particularly for the blue and amber light regions, have only partly been explored. This research aimed to characterize the effects of amber + blue light wavelengths and bandwidths on tomato (Solanum lycopersicum cv. Beefsteak) growth, morphology, and production efficiency. Tomato seedlings were subjected to four different light treatments for 60 days: narrow amber light (595 nm), narrow blue + narrow amber light (430 nm + 595 nm) with a 1:10 ratio, white LED (455 nm + 595 nm), and a high-pressure sodium (HPS) lamp (control). The highest mean fresh mass yield occurred with the narrow blue + narrow amber light (479 g), followed by white LED at 20% less, HPS at 34% less, and narrow amber at 40% less. Dry mass and plant height were similar among light treatments. Supplementing narrow amber light with 430-nm blue light led to a 20% increase in chlorophyll content. Findings indicate that narrow amber light is more efficient in biomass accumulation than broad amber light and that precise selection of different blue and amber wavelengths can greatly impact the growth and development of tomato seedlings. This energy-efficient narrow-wavelength combination shows improvement over white LED lighting for maximizing tomato growth. Full article

Light is a fundamental environmental parameter for plant growth and development because it provides an energy source for carbon fixation during photosynthesis and regulates many other physiological processes through its signaling. In indoor horticultural cultivation systems, sole-source light-emitting diodes (LEDs) have shown great potential for optimizing growth and producing high-quality products. Light is also a regulator of flowering, acting on phytochromes and inducing or inhibiting photoperiodic plants. Plants respond to light quality through several light receptors that can absorb light at different wavelengths. This review summarizes recent progress in our understanding of the role of blue and red light in the modulation of important plant quality traits, nutrient absorption and assimilation, as well as secondary metabolites, and includes the dynamic signaling networks that are orchestrated by blue and red wavelengths with a focus on transcriptional and metabolic reprogramming, plant productivity, and the nutritional quality of products. Moreover, it highlights future lines of research that should increase our knowledge to develop tailored light recipes to shape the plant characteristics and the nutritional and nutraceutical value of horticultural products. Full article