Search Results (1,817)

Cadmium (Cd) is a potentially toxic element that impairs plant growth and threatens food safety and human health. This study aimed to investigate the effects of sulfur (S) supplementation on Cd uptake and tolerance in rice under hydroponic conditions. Rice seedlings were exposed to Cd stress and treated with S at different concentrations. Physiological traits, oxidative damage markers, thiol compounds, and ionomic profiles in rice plants were assessed. S supplementation reduced Cd-induced growth inhibition, restoring plant biomass. Although Cd accumulation increased with S treatment, it was accompanied by enhanced antioxidant responses, scavenging reactive oxygen species (ROS) and malondialdehyde. S application increased the production of thiol-containing compounds, including γ-glutamylcysteine, glutathione, and phytochelatins, which helped chelate Cd and sequester it in vacuoles, particularly in roots. Additionally, S supplementation altered the essential nutrient composition in rice tissues, particularly the uptake of N, P, and K, while influencing levels of Ca, Mg, and other essential elements. S supplementation enhanced rice tolerance to Cd stress by reestablishing ROS balance, activating thiol-based detoxification pathways, and regulating mineral nutrient balance. Furthermore, sulfur (S) exhibited a dual effect in plants, enhancing cadmium (Cd) uptake while also promoting its detoxification, underscoring its role in improving crop resilience in contaminated soils. Full article

Phosphorus (P) deficiency severely limits maize growth and yield, yet early detection remains challenging, as visible symptoms appear only after prolonged starvation. This study evaluated the capability of hyperspectral imaging (HSI) combined with machine learning to detect P deficiency in maize seedlings at both symptomatic and pre-symptomatic stages. Two greenhouse experiments were conducted: a long-term pot system under high and low P conditions and a short-term hydroponic experiment with three P concentrations of 500, 100, and 0 μmol/L phosphate (Pi). After long-term P deficiency, significant reductions in shoot biomass and Pi content were observed, while root biomass increased and nutrient profiles were altered. Hyperspectral signatures revealed distinct wavelength-specific differences across visible, red-edge, and near-infrared (NIR) regions, with P-deficient leaves showing lower reflectance in green and NIR regions but higher reflectance in the red band. A multilayer perceptron machine learning model achieved 99.65% accuracy in discriminating between P treatments. In the short-term experiment, P deficiency significantly reduced tissue Pi content within one week without affecting pigment composition or photosynthetic parameters. Despite the absence of visible symptoms, hyperspectral measurements detected subtle spectral changes, particularly in older leaves, enabling classification accuracies of 80.71–84.56% in the first week and 85.88–90.98% in the second week of P treatment. Conventional vegetation indices showed weak correlations with Pi content and failed to detect early P deficiency. These findings demonstrate that HSI combined with machine learning can effectively detect P deficiency before visible symptoms emerge, offering a non-destructive, rapid diagnostic tool for precision nutrient management in maize production systems. Full article

Stevia is a natural source of high-intensity sweeteners, collectively known as steviol glycosides (SG), which are approximately 300 times sweeter than sucrose and widely used as sugar substitutes. This study examines the impact of five different red-to-blue (R:B) light ratios on SG content and yield in hydroponic Stevia across four growth stages. Results indicate that the highest and lowest leaf dry weights were recorded in the R1B0 (R:B = 1:0) and R0B1 (R:B = 0:1) groups, at 2.88 and 1.98 g/plant, respectively, reflecting a 45.45% difference. The total SG content in dried leaves was highest in R0B1 (196.32 mg/g) and lowest in R1B0 (115.16 mg/g), with a 70.48% variation. The highest and lowest total SG yields (YSG) per square meter were observed in R0B1 (46.56 g/m²) and R50B37 (35.70 g/m²), differing by 30.42%. Stage-specific optimal YSG values were identified, with designated growth stages P1 (early vegetative growth phase), P2 (early leaf development phase), and P3 (late leaf development phase) favoring R4B1 and P4 (leaf senescence phase) favoring R0B1. These findings suggest an optimized lighting strategy for the four growth stages of hydroponic Stevia, sequentially applying R4B1, R4B1, R4B1 and R0B1 to enhance biomass accumulation and SG production at different developmental stages. Full article

Toxic aluminum (Al) and iron (Fe) alter the hormonal balance of plants, leading to metabolic disorders and growth inhibition. Plants adapt to abiotic stress by optimizing phytohormone biosynthesis. However, the impact of toxic Al and Fe on plant hormonal status is poorly understood. Pea cultivar Sparkle and its mutant E107 (brz), accumulating Al and Fe due to disfunction of metal transporter gene OPT3, were cultivated in hydroponics supplemented or not with 80 µM of AlCl₃ or 300 µM of FeCl₃. Root and shoot biomass of E107 decreased due to Al or Fe treatments approximately by 30%, whereas growth of Sparkle was not affected. The Al and Fe content in the roots and shoots of the metal-treated mutant was circa twice that of Sparkle. Treatment with Al and Fe reduced the content of nutrients (Ca, K, Mg, S) in roots and/or shoots in both genotypes. Compared with Sparkle, untreated E107 possessed lower IAA and higher ethylene and tZR contents in roots but lower GA3, DHZ and tZ content in shoots. Mutant E107 had: lower GA3 and ethylene but higher DHZ, tZ and tZR contents in Al-treated roots; higher ABA, SA, IAA, GA3, DHZ, and tZ contents in Al-treated shoots; lower ABA and SA but higher JA, GA3, DHZ and ethylene contents in Fe-treated roots; higher ABA, SA, IAA, GA3, DHZ, and tZ contents in Al-treated shoots; higher ABA, JA, and GA3 but lower ethylene and tZR contents in Fe-treated shoots. Metal toxicity mainly reduced the content of phytohormones in roots and increased it in shoots. Hormonal disturbances were more significant in E107 than in Sparkle, and the effect of Al was stronger than Fe. Thus, toxic Al and Fe lead to complex, metal- and organ-specific changes in the hormonal status of E107. Hormonal changes might be associated with both defense reactions and the toxic effects of metals on plants. Full article

To elucidate the cooperative regulatory mechanisms underlying Paraburkholderia sp. GD17-mediated salt tolerance in cucumber plants. Hydroponically grown cucumber plants were inoculated with GD17 and subsequently subjected to NaCl treatment. Physiological, biochemical parameters, as well as gene expression profiles, were comprehensively analyzed. GD17 inoculation significantly improved plant growth, developmental performance, and salinity tolerance. Under salt stress, GD17-inoculated plants exhibited higher leaf nutrient contents compared to non-inoculated controls, particularly an elevated K⁺/Na⁺ ratio, which was closely associated with the upregulated expression of Na⁺ extrusion-related genes. A substantial increase in proline content and the corresponding biosynthesis-related gene expression indicated that enhanced osmoprotectant synthesis played a critical role in GD17-conferred salt tolerance. Phytohormone levels and their signaling-related gene expression were also significantly upregulated in GD17-inoculated plants under salt stress. Moreover, transcription factor gene expression was markedly increased in GD17-treated plants following salt exposure. GD17 inoculation alleviated salt-induced photosynthetic inhibition, as demonstrated by improved photosynthetic efficiency and reduced suppression of photosynthesis-related gene expression. Transcriptional profiling further revealed that starch degradation, photorespiration, and the pentose phosphate pathway were crucial for GD17-mediated salt tolerance. Reduced oxidative damage, driven by enhanced antioxidative activity, further contributed to the observed protective mechanisms. This study demonstrates that the application of Paraburkholderia sp. GD17 concurrently enhances cucumber growth and salinity tolerance, effectively resolving the trade-off between growth and defense. Multi-level analyses provided comprehensive mechanistic insights into these synergistic effects. Full article

Efficient water management is essential for sustainable agriculture, particularly for crops like carrots that are traditionally grown in soil systems with high water consumption, averaging 4500–6000 m³/ha. Hydroponics offers a potential alternative due to its higher water-use efficiency, yet root crops have been understudied because of system design and economic challenges. This study evaluated the effects of different hydroponic solution volumes on the growth of carrots (Daucus carota cv. Mokum) in a Deep-Water Culture (DWC) system to address knowledge gaps regarding their feasibility in soilless production. Experiments were conducted in a controlled greenhouse using three solution volume treatments (50% with 10.75 L, 75% with 16.13 L, and 100% with 21.50 L) applied to 12 plants per treatment across two repeated experiments. Biomass production, water use efficiency, and total carotenoid concentration were assessed after eight weeks. The 100% (21.50 L) volume treatment produced the greatest shoot and root biomass, whereas the 50% (10.75 L) volume treatment significantly increased total carotenoid concentration, particularly in the second trial. Despite lower water inputs, water use efficiency did not differ statistically among treatments. These results indicate that carrots can be successfully cultivated in DWC systems, though further optimization, such as using narrower containers, may be required to improve efficiency and competitiveness with soil-based production. Full article

The demand for food has increased due to the world’s expanding population, which has also put pressure on vital resources like water, land, and nutrients. Therefore, in order to guarantee food security, it is imperative to establish alternative, sustainable, and dependable strategies. In recent decades, researchers have developed novel food production methods that collectively enhance the efficiency and sustainability of food systems. Among these, aquaponics stands out as an advanced and eco-friendly agricultural technology that integrates aquaculture and hydroponics. In this system, fish waste from the aquaculture unit is utilized as a nutrient medium in the hydroponic subsystem to grow edible plants. This review aims to assess the potential of aquaponics to produce high-quality fruits, vegetables, and fish while minimizing environmental impacts without relying on chemical fertilizers. The study focuses on system design, nutrient cycling, and productivity parameters to assess its feasibility under Potohar conditions. The expected outcome is to demonstrate that aquaponics can enhance food quality, conserve resources, and uplift the socio-economic status of farming communities by alleviating poverty. Full article

Natural rubber (NR) is essential to the medical, industrial, defense and transportation industries. Alternative rubber crops are needed to supplement increasing rubber demands which cannot be met by the tropical rubber tree, Hevea brasiliensis, and to protect supplies in the event of a rubber tree crop collapse, political strife or a pandemic disrupting global rubber supply chains. Taraxacum kok-saghyz, rubber dandelion, has high-molecular-weight NR, substantial rubber content and the ability to grow in temperate regions. It can also grow hydroponically or aeroponically in controlled environments. This work presents a scenario-based cost analysis of requirements to scale up hydroponic rubber dandelion to replace the 1 million metric tons of imported rubber consumed annually by United States manufacturers. Two scale-up scenarios were considered: a single-level, deep water culture greenhouse and an indoor, ten-level hydroponic vertical farm built in a warehouse. Fuel usage, operating costs, electricity consumption, beneficial insect applications, fertilizers, cooling, and more were included for each case. The costs of operation and construction were compared to the value of products to determine potential annual profit. Sensitivity analyses revealed several scenarios which would drastically improve the economics of the hydroponic facilities. A combination of multiple factors may allow economic feasibility. Hydroponic rubber dandelion production can be profitable on a small scale (up to 15 MT of TNR/year) provided leafy greens and inulin are included as coproducts. The validity of scaling up such a system to 100,000 MT TNR/year to meet 10% of US manufacturing requirements depends heavily on successful research-based gains in TNR concentration and root size, the difference in TNR price between a commodity price and a specialty NR, and upon whether or not tropical rubber tree NR is able to continue to provide a stable source of NR for the US. Full article

The aim of this study was to investigate how delayed fertilization with individual macronutrients (N, P, K, Ca, Mg, and S) affects the growth, yield components, biomass, and spectrophotometric indicators of spring wheat grown under controlled hydroponic conditions. Nutrient deprivation was initiated at BBCH stage 23 and maintained for 21, 28, 35, or 133 days, corresponding to BBCH stages 30, 32, 37, and 99, respectively. In selected treatments, the complete nutrient solution was subsequently restored until harvest to evaluate recovery potential. N, P, and Ca deprivation exerted the strongest negative effects on biomass accumulation across all deprivation durations. Compared to the fully supplied control, biomass was reduced by 60% under N deprivation and by 44.5% under P deprivation after 21 days. After 35 days, calcium deprivation resulted in a 97.7% reduction in biomass. Following 133 days of deprivation, biomass was reduced by 98%, 96.8%, and 95.9% under N, calcium, and P deficiencies, respectively. Root mass followed a similar pattern: after 21 days, it decreased by 52.46% (N) and 36.44% (P); after 28 days—by 57.4% (N) and 52.7% (P); after 35 days—by 90.7% (Ca), 66% (N), and 59.1% (P); and after 133 days—by 95.1–90.1% (Ca, N, P). Magnesium deprivation caused substantial reductions in growth parameters, reflecting its central role in chlorophyll structure and photosynthetic efficiency. Sulfur deprivation resulted in moderate but consistent biomass suppression and spectral divergence, indicating its importance in protein synthesis and redox regulation. Short-term deficiencies allowed partial recovery of growth and productivity, whereas long-term deprivation induced pronounced morphological alterations linked to stress adaptation. These effects were further confirmed through in vivo spectral reflectance measurements compared to healthy control plants. Full article

Phthalate esters (PAEs) are ubiquitously emerging pollutants in the environment and have a notably high detection rate in tea; they can leach out during consumption and pose potential risks to human health. However, the process of PAEs entering and accumulating in tea plants is undocumented. This study investigated the uptake of PAEs in tea plant seedlings, focusing on both root and foliar pathways under hydroponic conditions. In controlled indoor deposition experiments, PAEs on fresh tea leaves underwent rapid degradation within five days, with the degradation rates ranging from 66.98% to 81.69%; outdoor rates exhibited even higher degradation rates. This degradation process followed first-order kinetics. The results revealed that tea plants were capable of absorbing and translocating PAEs via roots and leaves, culminating in their accumulation in various tea plant tissues. The Root Concentration Factor (RCF) was highest for di(2-ethylhexyl) phthalate (DEHP). Conversely, the shoot concentration factor, Leaf Concentration Factor, and Translocation Factors for the leaves, stems, and roots for the PAEs were inversely related to the RCF. The moderated mediation analysis suggested that root concentration was strongly influenced by translocation-mediated pathways. However, leaf concentration was largely not mediated by the translocation pathways. These findings indicate that both root uptake and foliar deposition can contribute to PAE accumulation in tea plants, providing a basis for source apportionment and for designing targeted control strategies to reduce PAE contamination in tea production systems. 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

Modern agriculture faces significant challenges, such as population growth, the reduction in productive agricultural land, and, most importantly, climate change. To address these issues, non-thermal plasma treatment of seeds and plants has emerged as a promising alternative to conventional chemical-based methods. This advanced technology, a powerful chemical reactor in the gas phase, has various applications, from stimulating seed germination and plant growth to controlling pathogens. The effects of non-thermal plasma on seeds include morphological and chemical changes in the seed coat, increased permeability and water uptake, and the activation of some internal biochemical mechanisms. Studies have demonstrated improvements in germination, plant development, and the activation of internal biochemical mechanisms with the intensified production of secondary metabolites. Non-thermal plasma also contributes to reducing the microbial load, providing an effective and environmentally friendly method of disinfection. This review synthesises the current knowledge on non-thermal plasma sources used in plasma agricultural applications for seed treatments, emphasising that in some cases the exposure of seeds to such discharge stimulates germination and also promotes early seedling growth. In addition, it highlights reported biochemical and nutraceutical improvements, including changes in antioxidant capacity, phenolic content and other bioactive compounds which add considerable value to the resulting plants. Finally, the decontamination potential is discussed, along with results discussing the potential of NTP to decontaminate seeds, associated with an extension to the shelf-life of products and identifying key challenges and research gaps for implementing this technology in agricultural practices. The integration of this technology into modern agriculture, including vertical farms and hydroponic systems, opens up the prospect for more sustainable and productive agriculture. However, scaling up the process and optimising processing parameters remain important challenges that require further attention, research and technological development. Full article

Controlled environment agriculture (CEA) relies on hydroponic systems to achieve high yields, yet optimizing plant performance remains a challenge. Beneficial endophytic bacteria offer a sustainable solution by promoting growth and nutrient uptake. Here, we investigated the mechanistic basis of growth enhancement in lettuce (Lactuca sativa) inoculated with Pseudomonas psychrotolerans IALR632 in a nutrient film technique (NFT) system. Growth measurements showed significant increases in shoot and root biomass and leaf greenness. RNA-seq profiling at 4, 10, and 15 days after transplanting revealed dynamic transcriptional reprogramming, with 38, 796, and 7642 differentially expressed genes, respectively. MapMan and GO analyses indicated up-regulation of pathways related to cell wall remodeling, lipid metabolism, nitrogen assimilation, and stress adaptation, alongside modulation of ethylene signaling. Root bacterial microbiome through 16S metabarcoding sequencing demonstrated distinct community shifts, confirmed by analysis of similarity (ANOSIM) (R = 1, p = 0.028), with enrichment of genera linked to nutrient cycling and plant growth promotion. These findings provide integrated molecular and ecological evidence that IALR632 enhances lettuce growth by coordinating host gene expression and rhizobiome restructuring, offering a mechanistic framework for microbial inoculant strategies in hydroponic horticulture. 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

This study investigated the effects of four LED light qualities, red+blue+far-red (WRS-LED), blue+red (BR-LED), blue (B-LED), and red (R-LED), and exogenous L-glutamic acid at 10 ppm on the growth and quality of red mustard spinach (Brassica rapa var. perviridis) cultivated in a plant factory using a recirculating deep-flow hydroponic system. Plants were exposed to four LED light quality treatments at 180 ± 10 μmol·m⁻²·s⁻¹ PPFD for 28 days after transplanting. L-glutamic acid at 10 ppm was applied once to the recirculating nutrient solution 15 days after transplanting, resulting in 13 days of exposure prior to final harvest on day 28. All growth and quality parameters were measured at the final harvest after 28 days of cultivation. WRS-LED promoted the greatest biomass production. Additionally, vitamin C content, DPPH radical scavenging activity, and total phenolic content were highest under BR-LED and B-LED conditions. Notably, under B-LED, L-glutamic acid treatment increased total phenolic content to approximately twice that of the control. Leaf redness, expressed as Hunter a* values, was observed exclusively under BR-LED. Principal component analysis revealed that LED light quality was the primary determinant of treatment responses, with growth-related traits associated with WRS-LED and R-LED, and quality-related traits with B-LED and BR-LED. Overall, BR-LED combined with L-glutamic acid represents the most suitable treatment for red mustard spinach cultivation in plant factories, achieving a favorable balance between growth and nutritional quality. Full article