Search Results (460)

Sensitive detection of Escherichia coli O157:H7 (E. coli O157:H7) in food matrices remains an important analytical challenge. Here, a colorimetric biosensor was constructed based on a bimetal oxide nanozyme composed of Ce-Fe oxide. This biosensor achieved sensitive detection of E. coli O157:H7. The Ce-Fe oxide synthesized on the basis of deep eutectic solvents (DESs) had the advantages of low solvent consumption and short preparation time. By regulating the two key factors of metal valence and oxygen vacancy content, the peroxidase (POD) activity of the nanozyme was significantly improved. Compared with the single-metal oxide nanozyme Fe oxide, the addition of Ce increased the Fe²⁺/Fe³⁺ ratio from 0.37 to 0.49, implying a possible enhancement of electron transfer between Fe²⁺ and Fe³⁺. The detection limits (LODs) of the biosensor based on Fe oxide and that based on Ce-Fe oxide were 10² CFU/mL and 10¹ CFU/mL, respectively, comparable to existing validated methods. Moreover, these two biosensors achieved satisfactory recovery rates (91–104%) and RSDs (1.2–8.8%) in the spiked lake water, juice, and lettuce samples of E. coli O157:H7, indicating their high potential for application in spiked sample detection. In summary, the method proposed in this study for improving the POD activity of nanozymes through electron transfer in DES solutions is beneficial to the development of metal oxide nanozymes. Full article

CNN with a Residual Network-50 (ResNet-50) architecture installed on a Raspberry Pi 5 is used to detect invasive aquatic plants in this study. By using object detection, the model recognizes water hyacinth, water lettuce, and water thyme and labels and bounds them accordingly. Images are taken by hand or at predetermined times, and verified detections are saved for later use. The adjusted ResNet-50 demonstrated 80.1% precision and 44.35% recall on validation, with 86.78% validation accuracy and 86.08% test accuracy. Target species from actual samples were successfully identified by the system. Full article

Aquaponic systems are increasingly recognized as sustainable technologies for integrated fish and vegetable production. However, concerns remain regarding the potential internalization of human pathogens into vegetables grown in these systems. This study assessed the risk of pathogen internalization in lettuce leaves grown in aquaponic systems with Nile tilapia challenged with Escherichia coli or Vibrio cholerae. The system comprised nine fish tanks, eighteen hydroponic pipes, and eighty-one lettuce plants, with tanks assigned to three treatments. Samples of water, fish gut, fish blood, and lettuce leaves were collected. Microbiological analyses included selective culture, biochemical assays, and molecular identification. Although colonies consistent with E. coli and V. cholerae were recovered on selective media, molecular sequencing identified other bacterial species, including Aeromonas sp., Aeromonas caviae, Aeromonas veronii, Enterobacter hormaechei, and Citrobacter freundii. The findings indicate that conventional culture-based methods may produce false-positive results and highlight the importance of molecular confirmation. Notably, pathogenic bacteria associated with tilapia were detected and appeared capable of disseminating through the system and internalizing into lettuce tissues. This result highlights the need for biosecurity measures, contamination monitoring, and the combined use of conventional and molecular diagnostic tools to ensure accurate pathogen detection and compliance with international food safety standards. Full article

Lettuce (Lactuca sativa L.) is a leafy herb that contains many useful nutrients, allowing it to easily overcome the threats to food security in countries of the Global South by adding fiber/bulk, folate and other available nutrients. In 2020, almost 220 metric tons of lettuce was produced in Pakistan. This high production needs attention to meet the demand. Southern Pakistan is facing water crises and the hydroponic system is one revolutionary technique which can allow the region to meet its food demand. In this experiment, different treatment combinations were used to study their effects and evaluate the best combination of nutrients to get the maximum production of lettuce. Results are concluded on the basis of last-week (5th week) production of shoot and root mass. Treatment one (T1) performed outstanding overall out of all four treatments across all parameters. Maximum average root and shoot length (RL, SL) was observed in treatment one (T1) at 5.94 cm and 15.50 cm respectively. Shoot length is directly proportional to production of the head of the plant. For root and shoot weight (RW, SW) treatment 1 (T1) is more effective than treatment 2 (T2). For treatment 1, root weight (RW) was recorded at 0.09 g and shoot weight (SW) was 0.22 g. The hydroponic system demands huge capital investment, which can be compensated by high production of crops. To increase the efficiency of the system, there is a dire need to calculate optimum nutrient combinations for application to the crop for a sound food security plan. Full article

Nanoplastics (NPs) are increasingly detected in agricultural soils, yet their influence on arsenic (As) transfer and plant toxicity remains unclear. Lettuce (Lactuca sativa L.) was cultivated in farmland soil with a naturally high As background (98.8 mg·kg⁻¹) to assess how polyethylene nanoplastics (PE NPs) affect rhizosphere conditions, As accumulation, and plant performance. PE NPs partially buffered soil acidification but reduced rhizosphere water content, while total soil As remained largely unchanged. Leaf As increased by 35–39%, with reduced biomass (up to 30%) and lower chlorophyll status (SPAD ~7% lower). Metabolomic analyses indicated dose-dependent alterations in central carbon metabolism and phenylalanine-related antioxidant metabolites, including suppressed tricarboxylic acid cycle intermediates at higher PE levels. Overall, PE NPs enhanced transfer of background As to edible leaves and intensified phytotoxicity, underscoring the need to consider nanoplastics in risk assessment of As-affected soils. Full article

Micronutrient addition to soil is crucial for improving crop yield. Within the framework of the circular economy, it is necessary to seek more efficient fertilizers. This would reduce fertilizer consumption while serving as a strategy to mitigate the negative effects of climate change. This study proposes the combined use of a traditional source of a Zn fertilizer (ZnSO₄) together with wood biochar to improve lettuce (Lactuca sativa L.) crop yield. An experiment was designed in which a dose of 8 mg Zn kg⁻¹ as ZnSO₄·7H₂O was added to Cambisol soil, mixed with or without biochar (5%), for lettuce growth. Among other soil properties, Zn bioavailability, microbial biomass, and available water were monitored in the soil, while photosynthetic pigments, Zn content, and biomass production were determined in plants. All treatments increased plant biomass production. Biochar treatments (biochar and biochar/ZnSO₄) increased fresh biomass by 324%, while ZnSO₄ addition resulted in a 158% increase in lettuce yield. This can be due to several factors, such as biochar being a C source, the improvement of soil water content after biochar addition, and the increase in Zn leaf content in all treatments with respect to the control soil. All of these likely had a positive effect on photosynthesis. This is corroborated by the increase in total chlorophyll, chlorophyll, and carotenoids in the treatments with ZnSO₄, biochar/ZnSO₄, and biochar. The application of biochar alone increased this property by more than 168%, with a positive impact on soil quality. Our research demonstrates that it is possible, in some cases, to prepare fertilizers combining ZnSO₄ and biochar, leading to increased plant Zn uptake and improved crop yield. Full article

Poly-γ-glutamic acid (γ-PGA) can regulate soil physicochemical properties and enhance crop yield. However, the effect of γ-PGA molecular weight (Mw) on plant growth remains unclear. In this study, we investigated the effects of γ-PGAs with low (70–100 kDa), high (700–1100 kDa), and ultra-high (>3000 kDa) Mws on lettuce growth and soil properties. The results showed that γ-PGA application reduced the infiltration rate of red soil. In pot experiments, γ-PGAs with different Mws at 0.1% promoted lettuce growth, and blade length and width increased with increasing Mw. However, the excessive application of ultra-high Mw γ-PGA inhibited lettuce growth. Soil chemical properties revealed that γ-PGA treatments significantly increased soil ammonium nitrogen and available potassium content. Furthermore, bacterial community structure analysis indicated that adding γ-PGA reduced bacterial diversity and richness, particularly under low and high Mw γ-PGA treatments, while increasing the relative abundance of beneficial plant-associated bacteria, including Proteobacteria and Acidobacteriota. Overall, ultra-high Mw γ-PGA exhibited the strongest effects on soil water retention and nutrient regulation, whereas low application rate was more favorable for plant growth. These findings can provide insights into the agricultural application of γ-PGA. Full article

Plasma-activated water (PAW) is enriched with reactive oxygen and nitrogen species (RONS). Application of PAW in plant cultivation demonstrated that RONS promote seed germination and early plant growth, as well as stimulate plant defense mechanisms. The aim of this paper was to investigate the potential of reactive nitrogen species in PAW to partially replace urea fertilizer nitrogen in lettuce cultivation without resulting in a negative effect on growth and mineral composition. Lettuce was grown under two treatments: urea only and a combined treatment in which 10% of the urea-derived nitrogen was replaced by an equivalent amount of nitrogen supplied via plasma-activated water (PAW). Plant growth parameters of lettuce (number of leaves, head weight, rosette diameter and height, and dry matter weight) were measured. Concentrations of 21 elements in the plants were analyzed using inductively coupled plasma optical emission spectroscopy (ICP—OES). Results showed no significant difference in growth parameters between the two treatments, as well as no significant difference between treatments in the concentrations of most elements except magnesium, boron and sodium. The results demonstrate that PAW reactive nitrogen can partially substitute for nitrogen from synthetic fertilizer without negative effects on the growth and nutritional content of lettuce. The study contributes to the development of sustainable horticultural fertilization practices and the adoption of environmentally friendly technologies. Full article

This study evaluated productive performance, nutrient use efficiency, and nitrogen and phosphorus mass balance in an intensive aquaponic polyculture system combining Nile tilapia (Oreochromis niloticus), channel catfish (Ictalurus punctatus), lettuce (Lactuca sativa), and spinach (Spinacia oleracea) under high biomass density (40 kg m⁻³). Nine treatments were established through a 3 × 3 factorial combination of fish (tilapia:catfish = 75:25, 50:50, 25:75) and plant (lettuce:spinach = 75:25, 50:50, 25:75) species ratios and evaluated over three consecutive 60-day production cycles. Nitrogen and phosphorus use efficiencies differed significantly among treatments, reaching maximum values above 50% for NUE and 47% for PUE in catfish-dominant systems with higher spinach proportions, indicating improved nutrient recovery and reduced losses. These treatments also produced greater fish biomass, whereas lettuce-dominant combinations favored plant yield. Water quality remained within acceptable ranges, although higher catfish proportions were associated with lower dissolved oxygen and increased nitrogen availability. Overall, results demonstrate that optimizing fish–plant species ratios enhances nutrient retention and sustainable productivity in intensive aquaponic systems. Future research should explore adaptive species ratio management and economic feasibility to support large-scale implementation of polyculture aquaponics. Full article

In the cold and arid regions of northern China, efficient water and nitrogen (N) management is critical for the sustainable production of leafy vegetables. Simplified models that estimate crop N and water transpiration demands using simple inputs based on climate parameters become an important method for making precise suggestions on N and irrigation application at a regional scale. This study developed and validated a regionally adapted version of the VegSyst model, named VegSyst-CH, based on a multi-year open-field experiment from 2021 to 2023. Model parameters were calibrated using data from the 2021 growing season and validated with independent datasets from 2022 and 2023. A critical N concentration (CNC) curve was established to describe the relationship between biomass accumulation and N content. VegSyst-CH, with a radiation use efficiency of 1.94 g MJ⁻¹, demonstrated high simulation accuracy for crop growth. The model showed a good predictive performance of N uptake under medium (N1) and high (N2) N treatments, with coefficients of determination (R²) above 0.80 across years and normalized root mean square error (NRMSE) values generally below 30%. The VegSyst-CH model also showed high accuracy in simulating crop evapotranspiration (ETc) over three consecutive growing seasons (2021–2023), with the dynamic trends of cumulative ETc closely aligning with measured values and the coefficients of determination (R²) consistently exceeding 0.90. These results validate the model’s robustness and applicability across different years. In conclusion, the VegSyst-CH model has strong spatiotemporal regulation capacity and climatic responsiveness, offering a robust decision support tool for precision fertilization and irrigation in open-field lettuce production in cold and arid regions. Full article

Desertification in Mediterranean drylands threatens food security. This study evaluated biochar–compost amendments on drought-affected sandy–calcareous soils, focusing on carbon (C) and nitrogen (N) dynamics. Laboratory soil incubations revealed that biochar reduced C mineralization, aiding long-term storage, but also decreased N mineralization, signaling potential short-term immobilization. However, leaching experiments showed that incorporating 2%, 5%, 10%, and 20% biochar into compost significantly reduced C losses by 22, 26, 36, and 48%, respectively, and N losses by 37, 67%, 45%, and 65%, respectively. In water-stressed lettuce trials, the use of compost alone could only yield 30% of the yield obtained in unstressed lettuce treated with compost. While the addition of 2–5% biochar to compost enabled the conservation of 44–45% of the yield of unstressed lettuce, a 10% biochar amendment doubled this number (88%). Nonetheless, a higher dose of 20% biochar in the compost offered no additional benefit with 84% of the yield of unstressed lettuce amended with compost. These findings position biochar–compost as a key strategy to enhance soil fertility and water-use efficiency. To counteract short-term N immobilization, the study recommends further investigation of early application combined with supplemental fertilization or fractionated biochar supply (over 2–3 years). Ultimately, tailoring biochar formulations to specific local conditions is essential to balance immediate crop productivity with long-term soil health. Full article

Soil salinity is a major constraint on global agricultural productivity. This study evaluated the efficacy of a cell-free extract from Trichoderma hamatum (designated BEYF) in enhancing salt stress tolerance in lettuce (Lactuca sativa). Lettuce plants under normal and salt-stressed conditions exposed to 200 mM NaCl were treated with either water or YF (the working solution of BEYF) at concentrations of 0.05, 0.10, and 0.25 mg/L. Compared to the control, YF application significantly improved plant growth under salt stress, as indicated by increased plant height, biomass, leaf area, and other agronomic traits. Physiologically, YF mitigated oxidative membrane damage, as indicated by reduced electrolyte leakage and malondialdehyde (MDA) content, while promoting the accumulation of the osmoprotectant proline. Histochemical staining further confirmed that YF effectively suppressed hydrogen peroxide (H₂O₂) accumulation and preserved cell viability under salt stress. At the molecular level, YF significantly up-regulated the expression of key stress-responsive genes, including those involved in abscisic acid biosynthesis (NCED1, NCED2), signaling (WRKY58), and proline synthesis (P5CSs). Collectively, our findings demonstrate that BEYF enhances lettuce salt tolerance through integrated physiological, cellular, and transcriptional adaptations, supporting its potential as a sustainable biostimulant for improving crop cultivation in saline soils. Full article

Plant Growth-Promoting Rhizobacteria (PGPR), represent a promising tool for the development of sustainable agriculture practices. Although numerous strains have been described in the literature, their characterisation often overlooks the ability to sustain functional activity under common abiotic stress conditions, such as water deficit and high salinity. The present study aimed to isolate putative PGPR strains from different environmental and biological matrices, characterise their key plant growth-promoting traits, and evaluate their effectiveness in improving plant growth under water and salt stress conditions. The isolated strains were initially tested in vitro for phytohormone production, phosphate solubilisation, and siderophore production. Selected Bacillus and Pseudomonas strains exhibiting the most promising traits were tested in a preliminary greenhouse pot test using lettuce (Lactuca sativa), followed by assays under drought stress (50% water reduction) and salt stress (100 mM NaCl). The results demonstrated that the two Bacillus velezensis strains (PB_8 and CSS_12) significantly enhanced plant growth by increasing foliar biomass and root development improving pigment content, and mitigating stress-induced damage. Overall, these findings support the potential of PGPR-based strategies for low-impact agricultural practices and enhancing plant resilience under stress conditions. Full article

Climate change has led to rising temperatures and increasingly extreme weather conditions, largely driven by human activity, including agriculture. The food and agriculture sector is responsible for approximately 21–37% of global greenhouse gas (GHG) emissions. In response to climate change, various innovative agricultural systems have emerged in recent decades. Among them, soilless systems represent revolutionary methods for producing large quantities of vegetables while using fewer inputs, including water, fertilizers, and pesticides. This study assesses the carbon footprint of two greenhouse-based lettuce (cv. Romana) growing systems using a cradle-to-gate life cycle assessment (LCA) approach. The first system employs an aeroponic growing method, whereas the second relies on a soil-based growing method within the greenhouse. To contextualize their environmental performance, the carbon footprints of these greenhouse cultivation systems are compared with those of the outdoor pot system. Results indicate that the highest Global Warming Potential (GWP) is associated with soil-based cultivation in the greenhouse, reaching 7.98 kg CO₂eq per kilogram of fresh weight (FW) lettuce, followed by the outdoor pot system (1.72 kg CO₂eq/kg), while the aeroponic system demonstrates the lowest GWP, achieving 0.98 kg CO₂eq/kg. The greenhouse structure contributed 9357.93 kg CO₂eq to the total GWP, representing 23% of the total impact in the aeroponic system and 22.7% in the soil-based greenhouse system. These findings suggest that soilless cultivation systems can provide a more sustainable and higher-yield alternative to soil-based methods, potentially reducing the environmental impact of vegetable production in the Mediterranean region. Full article

Amid global freshwater scarcity and soil salinization, brackish irrigation is a potential alternative, yet its effects under low-leaching soilless systems remain unclear. We tested brackish irrigation (30 mmol L⁻¹ NaCl; EC ≈ 4.8 dS m⁻¹, including fertilizer) on lettuce (Lactuca sativa L.) grown in peat–perlite substrates with non-saline (CK), mildly saline (M), and moderately–severely saline (S) initial salinity. Substrate moisture and bulk electrical conductivity (EC_b) were monitored at upper, middle, and deep layers with multi-depth sensors; lettuce physiological and growth traits were measured. Under negligible drainage, salt moved downward promptly after irrigation in CK, accumulated at the surface in M, and remained high with spatiotemporal variability in S. Brackish irrigation had minimal effects on biomass and water use efficiency in CK and M, but significantly reduced both in S. These findings support tailoring brackish irrigation to initial salinity severity and motivate future work to measure drainage and calibrate EC indices to establish operational thresholds. Full article