Search Results (416)

Enhancing the sustainability of growing media is an important objective in soilless vegetable cultivation. Here, we evaluated the potential of pine bark to replace perlite in coir-based substrates for lettuce (Lactuca sativa L. cv. ‘Godzilla’) cultivation. The experiment followed a factorial design with two coir-based substrate blends—one amended with perlite and the other with pine bark—and two nutrient solution EC levels (1.5 ± 0.2 and 2.5 ± 0.2 dS m⁻¹). The plants were cultivated in Styrofoam containers containing a substrate mix of 80% coir, 12% compost, and 8% perlite or pine bark (v/v). Replacing perlite with pine bark did not affect leaf macronutrient concentrations but increased leaf Fe and B levels. Increasing the EC of the nutrient solution increased leaf N, P, and K, with a significant rise in nitrogen. The substitution of perlite with pine bark in coir-based substrates did not affect leaf dry weight, head fresh weight, or chlorophyll content, total phenols, ascorbic acid, or proline, even under different salinity levels. The findings indicate the pine bark is an alternative to perlite, supporting comparable agronomic and quality outcomes in lettuce. Further research is recommended to confirm these results in crops with longer growing cycles. Full article

Background/Objectives: Bolting in lettuce (Lactuca sativa L.) is highly sensitive to elevated temperatures, leading to premature flowering and reduced crop quality and yield. Although SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1) is a well-known floral integrator in Arabidopsis, its role in heat-induced bolting in lettuce remains unclear. Methods: In this study, we generated CRISPR/Cas9-mediated LsSOC1 knockout (KO) lines and evaluated their phenotypes under high-temperature conditions. Results: LsSOC1-KO lines exhibited delayed bolting up to 18.6 days, and stem elongation was reduced by approximately 3.8 cm, which is equivalent to a 36.1% decrease compared to wild-type (WT) plants. Transcriptome analysis of leaf and bud tissues identified 32 up-regulated and 10 down-regulated genes common to leaf tissue (|log₂FC| ≥ 1, adjusted p < 0.05). Among them, GA20-oxidase1 was significantly down-regulated in both tissues, which may have contributed to delayed floral transition and possibly to reduced stem elongation, although tissue-specific regulation of gibberellin metabolism warrants further investigation. In contrast, genes encoding heat shock proteins, ROS-detoxification enzymes, and flavonoid biosynthetic enzymes were up-regulated, suggesting a dual role of LsSOC1 in modulating thermotolerance and floral transition. qRT-PCR validated the sustained suppression of flowering-related genes in LsSOC1 KO plants under 37 °C heat stress. Conclusions: These findings demonstrate that LsSOC1 is a key integrator of developmental and thermal cues, orchestrating both bolting and stress-responsive transcriptional programs. Importantly, delayed bolting may extend the harvest window and improve postharvest quality in lettuce, highlighting LsSOC1 as a promising genetic target for breeding heat-resilient leafy vegetables. Full article

This study evaluated the qualitative and quantitative performance of lettuce (cv. Romana) grown using different cultivation systems under Mediterranean greenhouse conditions equipped with photoluminescent glass panels. Five systems were compared: outdoor soil (PSO), indoor soil (PSI), aeroponic (A), hydroponic with inorganic nutrients (HSN), and hydroponic with organic nutrients (HSO). Morphological, physiological, and quality parameters were measured alongside solar irradiance and extended PAR. The results showed that aeroponics significantly outperformed other systems in fresh weight (52.7 g), photosynthetic pigments, and carotenoids, while HSO showed the lowest yield and quality. Although PSO had the highest antioxidant activity and phenolic content, it exhibited poor yield due to lower water use efficiency and light-induced stress. The PCA analysis highlighted distinct groupings among systems, with A linked to yield and pigment concentration, and PSO associated with antioxidant traits. Despite a 44.8% reduction in solar radiation inside the greenhouse, soilless systems—especially aeroponics—proved effective for maintaining high productivity and quality. These findings support the integration of soilless systems and photoluminescent technologies as sustainable strategies for high-efficiency lettuce production in controlled environments. Full article

Vertical farming allows for precise control of environmental conditions, including light quality, enabling the optimization of plant growth and the synthesis of specific phytochemicals. However, the effects of such conditions on postharvest quality remain underexplored. In this study, butterhead lettuce (Lactuca sativa cv. ‘Alyssa’) was grown for three weeks under light-emitting diode (LED) lighting (190 µmol m⁻² s⁻¹; 89% red, 11% blue), with or without supplemental far-red light (ca. 50 µmol m⁻² s⁻¹). Growth and quality parameters were assessed at harvest, followed by postharvest evaluation of fresh-cut lettuce stored under equilibrium modified atmosphere packaging (EMAP: 3% O₂, balance N₂) at 7 °C in darkness for 13 days. The respiration rate of the produce was also determined. Far-red light supplementation increased dry weight (+17%) and elevated glucose (+57%) and fructose (+64%) levels at harvest, without affecting fresh weight, pigment content, vitamin C, or sucrose levels. Although respiration rates during storage were about 54% higher for lettuce grown under far-red light, visual quality seemed slightly better preserved. Total aerobic psychrotrophic counts showed no significant differences between treatments at harvest or during storage. These findings suggest that far-red light can enhance certain quality traits of lettuce, particularly carbohydrate accumulation and dry weight, but the associated rise in respiration may limit these benefits postharvest. Further research is needed to clarify its long-term impact in vertical farming systems. Full article

The escalating demand for sustainable agriculture calls for innovative strategies that enhance crop resilience while minimizing dependence on synthetic fertilizers. This study evaluated the synergistic effects of a microbial consortium (PYS), organic fertilizer (OF), glycine (Gly), and indole-3-acetic acid (IAA) on lettuce under heat stress. The experiment was conducted in a greenhouse in Bangkok, Thailand, simulating tropical high-temperature conditions. The PYS+OF+Gly treatment significantly improved fresh weight, matching the performance of chemical fertilizer (CF) and indicating a strong growth-promoting synergy. Chlorophyll a, chlorophyll b, and carotenoid contents were higher in PYS or PYS+OF treatment, suggesting enhanced photosynthetic efficiency. At 60 days, PYS-based treatments also led to substantial increases in total phenolics and flavonoids, coupled with reduced lipid peroxidation and elevated antioxidant activities (DPPH, APX, CAT, POD, and SOD). However, vitamin C levels remained highest in the CF and OF controls, indicating a potential metabolic shift toward phenylpropanoid rather than ascorbate biosynthesis. Overall, our results demonstrate that combining microbial consortia with organic and biostimulant inputs could enhance growth, stress tolerance, and the nutritional quality of lettuce. This integrated approach presents a promising strategy for climate-resilient crop production and warrants further validation across different crops, environmental settings, and large-scale agricultural systems. Full article

The inclusion of the Internet of Things (IoT) in indoor agricultural systems has become a fundamental tool for improving cultivation systems by providing key information for decision-making in pursuit of better performance. This article presents the design and implementation of an IoT-based agricultural system installed in a plant growth chamber for hydroponic cultivation under controlled conditions. The growth chamber is equipped with sensors for air temperature, relative humidity (RH), carbon dioxide (CO₂) and photosynthetically active photon flux, as well as control mechanisms such as humidifiers, full-spectrum Light Emitting Diode (LED) lamps, mini split air conditioner, pumps, a Wi-Fi surveillance camera, remote monitoring via a web application and three Nutrient Film Technique (NFT) hydroponic systems with a capacity of ten plants each. An ATmega2560 microcontroller manages the smart system using the MODBUS RS-485 communication protocol. To validate the proper functionality of the proposed system, a case study was conducted using lettuce crops, in which the impact of different nutrient solution concentrations (50%, 75% and 100%) on the phenotypic development and nutritional content of the plants was evaluated. The results obtained from the cultivation experiment, analyzed through analysis of variance (ANOVA), show that the treatment with 75% nutrient concentration provides an appropriate balance between resource use and nutritional quality, without affecting the chlorophyll content. This system represents a scalable and replicable alternative for protected agriculture. Full article

In this study, we sought to improve the productivity of Far Eastern catfish (Silurus asotus) and tropical eel (Anguilla bicolor), which are high-value fish species in the Republic of Korea, as well as that of associated crops by applying biofloc technology (BFT)-based aquaponics systems. The following three systems were used: the flow-through system (FTS), BFT, and BFT aquaponics system (BAPs). Caipira lettuce (Lactuca sativa) was utilized and hydroponics (HP) was implemented to compare crop productivity. After 42 days of treatment, the BAPs and BFT systems improved fish productivity, with weight gain rates of 134.47 ± 1.80% in BAPs-cat, 130.38 ± 0.95% in BFT, and 114.21 ± 6.62% in FTS for S. asotus, and 70.61 ± 3.26% in BAPs-eel, 62.37 ± 7.04% in BFT, and 47.83 ± 1.09% in FTS for A. bicolor. During the experiment, the total ammonia nitrogen and NO₂⁻-N concentrations were stable in all plots. In the case of NO₃⁻-N, BFT showed an increasing tendency while both BAPs showed a decrease compared with that of the BFT. BAPs-cat (total weight: 224.1 ± 6.37 g) and HP (220.3 ± 7.17 g) resulted in similar growth. However, in BAPs-eel was 187.7 ± 3.46 g due to root degradation. Water content analysis showed that BAPs-cat and BAPs-eel contained sufficient K, Ca, P, and S, which are important for crop growth. Overall, the effect of BAPs on fish growth was higher than that of FTS. This study reveals that integrating BFT with aquaponics improves productivity for high-value fish and associated crops while maintaining stable water quality. This method offers sustainable, efficient production, reduces environmental impact, and provides insights for future research in sustainable aquaculture practices. Full article

Lettuce (Lactuca sativa L.) is one of the main leafy vegetables in the world, being present in several countries. Due to its composition, which includes a substance with antioxidant action and beneficial effects on health, it is consumed constantly. However, due to ongoing climate change that has had global effects, the crop has been suffering a reduction in productivity and quality. Thus, technologies aiming to mitigate the effects of climate extremes have been developed. In lettuce production, biostimulants make it possible to improve the growth and sustainable development of plants. This is due to their ability to activate physiological and biochemical processes in plants, resulting in an increase in the production of bioactive compounds such as vitamins, amino acids, and antioxidants. In addition, biostimulants contribute to improving the nutritional quality of lettuces, making them more resistant and adapted to different environmental conditions, resulting in a more sustainable development for the crop. This review aims to compile and discuss the available scientific evidence on the use of biostimulants in lettuce cultivation, addressing their mechanisms of action, the types of substances used, the results obtained in different cultivation systems, and their potential to promote more efficient and adaptable agriculture in the face of environmental changes. Full article

In the rock–soil–biology–water ecosystem, rock weathering provides essential plant nutrients. However, its supply is insufficient for rising crop demands under population growth and climate change, while excessive fertilizer causes soil degradation and pollution. This study innovatively irrigated with carbonate rock leachates to enhance soil nutrient availability. A pot experiment with lettuce showed that irrigation significantly increased soil NO₃⁻-N (+102.20%), available K (+16.45%), available P (+17.95%), Ca (+6.04%), Mg (+11.65%), and Fe (+11.60%), and elevated the relative abundance of Firmicutes. Lettuce biomass per plant rose by 23.78%, with higher leaf minerals (P, K, Ca, and Mg) and antioxidants (carotenoids and ascorbic acid). A field experiment further confirmed improvement of soil nutrient availability and peanut yield. This carbonate rock leachate irrigation technique effectively enhances soil quality and crop productivity/quality, offering a sustainable approach for green agriculture. Full article

Accurate, energy-efficient climate regulation is crucial for scaling smart greenhouse production. While nonlinear model predictive control (NMPC) can co-optimize yield and resource use, its efficacy hinges on short-range weather information and real-time solver feasibility. This paper investigates the performance of advanced NMPC strategies for smart greenhouse climate control, with particular emphasis on the roles of AI-driven disturbance prediction and warm-start initialization for real-time optimization. Six controller configurations, including feedback-only, LSTM-based forecast, and ideal disturbance models, each with and without warm-start, were tested in a 40-day simulation of a lettuce smart greenhouse. Performance metrics included final biomass, constraint violations, resource costs, profit, and solver time. Results show that feedback-only controllers maximize yield and profit, incurring higher CO₂ costs but lower heating costs, alongside greater constraint violations compared to the predictive strategies. Predictive and ideal disturbance-aware controllers effectively reduce resource consumption and improve constraint compliance at the expense of lower yields. Importantly, warm-start initialization significantly accelerates computation without affecting control quality. The study also demonstrates that penalty parameters, rather than economic weight settings, predominantly determine aggregate constraint violation. The findings provide actionable insights for designing and deploying NMPC-based greenhouse controllers, highlighting the importance of warm-start techniques and the trade-offs between productivity, resource efficiency, and environmental compliance. Full article

With the rapid expansion of the aquaculture scale, the environmental pollution caused by the accumulation of fish pond sediment (FPS) has become increasingly prominent, making it urgent to establish sustainable resource utilization solutions. This study investigates the potential of using FPS as a soil amendment to improve saline–alkali soil (SAS) quality and enhance vegetable growth, while also quantifying ecological benefits through Gross Ecosystem Product (GEP) accounting. A pot experiment was conducted to evaluate the effects of different FPS mass percentages (0%, 20%, 40%, 80%, and 100%) on the growth of three vegetables (water spinach, lettuce, and chili) and soil quality. The results demonstrated that FPS addition at ≥40% significantly improves SAS quality, reducing the pH and salinity (p < 0.05), while enhancing organic matter, nutrient availability, and microbial activity. Among the treatments, 80% FPS maximized vegetable yields, with water spinach achieving the highest edible biomass (37.32 g). Compared to the control, nutritional quality under ≥80% FPS treatment showed substantial increases: vitamin C (133.33–307.03%), soluble sugars (49.97–73.53%), and protein (26.14–48.08%). An economic analysis revealed that 80% FPS with water spinach cultivation generated peak ecological benefits (274,951 CNY·ha⁻¹; 185% above control). These findings provide a scientific basis and effective model for the resource utilization of FPS and the improvement of saline–alkali soil, offering significant implications for the sustainable development of agriculture and environmental protection. Full article

Aeroponics efficiently conserves water and fertilizer but faces energy sustainability challenges in maintaining high productivity and quality. This study aimed to identify critical growth phases of lettuce affected by management modes and assess resource/energy efficiency (cost per unit yield) to inform the development of sustainability strategies for lettuce production in a lettuce-dominant aeroponics system integrated with radish. Three management modes were tested: M1 (constant nutrient solution concentrations), M2 (variable nutrient solution concentrations), and M3 (combined variable nutrient solution concentrations and preharvest short-duration continuous light for 48 h). Plant parameters were dynamically measured in a 30-day cultivation cycle. The results showed that the intercropped lettuce exhibited peak growth at 15–25 days after transplanting, and nutrient solution adjustment enhanced the shoot weight and quality, with synergistic quality improvements under M3. However, preharvest lighting reduced the net photosynthetic rate via stomatal closure and lowered the effective quantum yield of photosystem II, preventing biomass increase. The preharvest short-duration continuous light elevated the soluble protein, ascorbic acid, and soluble sugar contents. For yield-focused systems, M2 alone achieved comparable shoot weight to M3 with higher energy efficiency. However, when simultaneously considering lettuce quality enhancement and the yield boost of radish in the intercropping system, M3 demonstrated potential for greater marginal benefits. Full article

Vertical farming systems offer an efficient solution for sustainable food production in urban areas. However, managing nitrate (NO₃⁻) levels remains a significant challenge for improving crop yield, quality, and safety. This study evaluated the effects of nitrate availability on growth performance, nutrient uptake, and water use efficiency in a vertical hydroponic system that intercropped lettuce (Lactuca sativa) with alfalfa (Medicago sativa). The experiment was conducted in a controlled vertical hydroponic system using Nutrient Film Technique (NFT) channels, with nitrogen levels set at 0, 33, 66, 100, and 133% of the standard concentration. The results indicated that the intercropping treatment with 66% nitrate (IC-N_66%) improved water use efficiency by 38% and slightly increased leaf area compared to the other intercropping treatments. However, the control group, which consisted of a monoculture with full nitrate supply, achieved the highest overall biomass. Ion concentrations, including nitrate, calcium, magnesium, and micronutrients, were moderately affected by the intercropping strategy and nitrate levels. These findings suggest that moderate nitrate input, combined with nitrogen-fixing legumes, can enhance resource efficiency in hydroponic systems without significantly compromising yield. These findings offer a promising framework for incorporating legumes into hydroponic systems, minimizing the need for synthetic inputs while maintaining yield. These results support the use of agroecological intensification strategies in highly efficient soilless systems. Full article

Most vegetable crop production in Mississippi (MS) occurs during the summer, characterized by high temperature and relative humidity. Lettuce yield and harvest quality are significantly affected by heat stress. To avoid the heat stress of the summer months, lettuce production in MS is either produced in controlled environments or during the winter months with cooler temperatures. This period, however, coincides with months with low solar radiation and shorter day length, resulting in a longer growing season and poor harvest quality. Therefore, this study was conducted to determine the optimum duration of light supplement on the growth, yield, and water use of greenhouse (GH) lettuce during the winter season in north Mississippi. In this study, three daily supplemental light duration regimes, 0 h, 4 h, and 8 h, starting at sunset, were evaluated across two lettuce cultivars, Green Forest (GF) and Ruby (RB). The study indicated that supplemental lighting significantly increased lettuce growth, yield, and water use. Although day length extension from 4 to 8 h of supplemental light had no yield benefits on the RB cultivar, extending day length from 4 to 8 h increased GF yield by 42%. It was also observed that the effects of light supplementation during low natural light quality at early or later growth stages differ between cultivars. Based on the results obtained from this study, a 4 h and 8 h post-sunset light supplementation is considered optimum for RB and GF lettuce cultivars, respectively, during the winter growing season in MS. Full article

The postharvest quality of lettuce (Lactuca sativa) is significantly influenced by the lighting environment during storage. This study evaluated the effects of green LEDs at 500 nm and 530 nm, white LEDs (400–700 nm), and dark storage on lettuce quality over 14 days at 5 °C. All treatments were applied at 10 µmol m⁻² s⁻¹ under a 12 h photoperiod. Quality parameters measured included moisture loss, relative water content (RWC), photosynthetic rate, chlorophyll content (SPAD), total soluble solids (TSSs), electrolyte leakage (EL), color change (∆E), texture (crispness), and overall visual quality (OVQ). Lettuce stored under green LEDs, particularly 530 nm, exhibited superior postharvest quality. Compared to dark storage, 530 nm reduced moisture loss by 7.1%, increased RWC by 9.2%, and reduced transpiration rate. The green light preserved photosynthetic activity (43% decline vs. 77% in the dark), increased TSS, reduced color change by 42%, improved crispness by 46.1%, and limited EL to 54.5%. Shelf life was extended by approximately four days. The 500 nm treatment showed notable improvements, including an 8.4% reduction in moisture loss, 8.2% higher RWC, a smaller photosynthesis decline (25%), and the lowest EL (53.1%). It improved color retention (∆E reduced by 45.3%) and crispness (46.8%). Both green wavelengths effectively maintained lettuce quality during cold storage, with 530 nm being the most effective overall. These results suggest that targeted green LED lighting is a promising, energy-efficient strategy to preserve postharvest quality and extend shelf life in leafy greens. Full article