Cadmium (Cd) contamination in agricultural soils threatens crop production and food safety. Although melatonin is known to enhance antioxidant defense, its role in cell-wall remodeling and Cd compartmentalization remains unclear. We investigated the effects of 100 μmol L-1 melatonin on Solanum nigrum exposed to 10 mg kg-1 Cd using physiological, biochemical, subcellular, transcriptional, and random forest analyses. Cd reduced biomass, photosynthetic rate, and Fv/Fm, whereas melatonin partially restored these traits. Melatonin also decreased Cd concentrations in roots, stems, and leaves and reduced root-to-shoot Cd translocation. Meanwhile, Cd partitioning to the cell-wall fraction increased from 56.7% to 67.5% in roots and from 55.1% to 66.5% in leaves, while organellar Cd partitioning was approximately halved. These changes were accompanied by increased pectin content and pectin-bound Cd, upregulation of pectin metabolism and Cd detoxification genes, enhanced antioxidant activity, and improved redox status. Random forest modeling identified ascorbate, photosynthetic rate, and pectin-bound Cd as key predictors of Cd tolerance. These findings indicate that melatonin enhances Cd tolerance through coordinated cell-wall sequestration and antioxidant defense while altering Cd allocation, with implications for phytoremediation efficiency.
This study reports the green extract assisted synthesis of manganese ferrite (MnFe2O4) nanoparticles using Phyllanthus emblica fruit extract as a natural reducing and stabilizing agent to develop multifunctional nanomaterials for forensic, environmental, and antibacterial applications. The green synthesized nanoparticles were characterized using XRD, HRTEM-SAED, FESEM-EDAX, UV-DRS, FTIR and VSM analyses, confirming a cubic spinel structure, high crystallinity, average crystallite size of 29 nm, and a narrow optical Eg of 1.9 eV. Synthesized nanoparticles demonstrated effective latent fingerprint visualization on both porous and non-porous substrates. MATLAB-assisted image processing and comparative similarity analysis yielded computational similarity scores ranging from 92.41% to 100% under the implemented workflow. Furthermore, the MnFe2O4 nanoparticles exhibited efficient visible-light-driven photocatalytic degradation of MG dye, achieving approximately 94% degradation at 5 mg/L and 92% at 20 mg/L within 20 min. In addition, the nanoparticles showed concentration-dependent antibacterial activity against Staphylococcus aureus, Bacillus.sp, Escherichia coli, and Klebsiella.sp, with a maximum zone of inhibition of 9 mm against Bacillus.sp. The observed multifunctional behavior is attributed to the synergistic effect of nanoscale size, magnetic properties, and phytochemical functionalization. These findings demonstrate that green-synthesized MnFe2O4 nanoparticles are potential eco-friendly multifunctional nanomaterials for advanced forensic fingerprint analysis, wastewater treatment, and antibacterial applications.
Tire wear nanoparticles (TWPs) pose an emerging environmental concern in agricultural systems. In this study, TWPs were characterized using dynamic light scattering, Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy/energy-dispersive X-ray spectroscopy, revealing predominantly submicron particles (average hydrodynamic diameter 284.6 nm), irregular morphology, and complex composition. The ICP analysis confirmed the presence of Zn, Cu, Cr, Pb, Ni, Cd, and As in the TWP matrix. A controlled pot experiment evaluated the effects of soil and foliar-applied TWPs at concentrations of 0.05-0.5 g kg-1 (soil) or g L-1 (foliar) on spinach (Spinacia oleracea L.). Fluorescence microscopy showed internalization of TWPs via both root and leaf pathways. Low soil concentration (0.05 g kg-1) transiently enhanced growth and metabolite accumulation, whereas higher concentrations (≥0.25 g kg-1 or g L-1) significantly reduced biomass, leaf area, photosynthetic traits, and growth indices. Antioxidant responses showed enzyme-specific modulation, with marked induction of peroxidase and catalase at higher TWP levels and variable superoxide dismutase responses depending on the exposure pathway. Metal analysis revealed concentration-dependent accumulation of Zn and non-essential metals, including Pb and Cd, in leaves, particularly at elevated TWP levels. These findings indicate that TWPs can enter plant tissues through both soil and foliar routes, alter morpho-metabolic processes, and promote metal accumulation, posing potential risks to food safety.
This study investigates the sustainable valorization of grass (Cynodon dactylon), an abundant lignocellulosic agricultural waste, as an eco-friendly adsorbent for the removal of synthetic dyes from aqueous systems. Both untreated grass (UGS) and treated grass with acetic acid (AAGS) and sodium hydroxide (SHGS) were prepared at varying concentrations (10% and 5%, respectively) to enhance surface functionality. Comprehensive characterization using FTIR, SEM, EDS, XRD, and BET analysis elucidated the physicochemical changes induced by acid and alkali treatment. Adsorption studies targeting Methylene Blue (MB), a cationic dye commonly found in textile effluents, were conducted under varying operational parameters, including dye concentration (5-60 mg/L), adsorbent dosage (0.25-1.25 gm), contact time (1-6 h), pH (2-12), and temperature dependence (30-70 °C). The 5% alkali-modified grass (5% SHGS) demonstrated superior adsorption efficiency, achieving 76.20% dye removal at pH 8 for an initial dye concentration of 5 mg/L. Kinetic data followed a pseudo-second-order model, suggesting physical adsorption as the dominant mechanism. In contrast, equilibrium data were best described by the Freundlich isotherm for MB (R2=0.99), indicating multilayer adsorption on a heterogeneous surface. The thermodynamic study mainly demonstrated the spontaneous and endothermic nature of MB adsorption. The process was found to be more effective at 50 °C temperature, highlighting its feasibility for low-energy wastewater treatment applications. This study advocates for the circular utilization of agricultural byproducts in environmentally sustainable remediation approaches for industrial dye contamination.
Selenium-enriched vegetables have high nutritional value and good flavor, which are beneficial to human health. To improve the selenium uptake of watercress, a pot experiment was conducted to study the effects of selenium combined with 400-fold diluted extracts of Artemisia argyi and tartary buckwheat (Fagopyrum tataricum) straw on its growth and selenium accumulation. Both extracts promoted root and shoot biomass, increased leaf chlorophyll and carotenoid contents, and enhanced POD activity. Compared with single selenium treatment, A. argyi straw extract raised root and above-ground selenium accumulation by 46.38% and 16.69%, while tartary buckwheat extract increased it by 39.10% and 5.41%. Their combined treatment increased selenium accumulation by 47.28% and 19.64%. The correlation analysis showed that the selenium content in the roots and above-ground parts of watercress had a positive correlation with the biomass of watercress, chlorophyll content, carotenoid content, and POD activity. In conclusion, the two extracts can promote watercress growth and selenium enrichment, and their combined application achieves a better effect.
Sustainable agriculture is increasingly challenged by soil degradation, environmental pollution, and climate change, necessitating the pragmatic and eco-friendly approach. This review systematically synthesizes the role of biochar as multifunctional soil management strategy in enhancing soil health and sustainable environmental management, with particular emphasis on the critical roles of feedstock type and pyrolysis conditions in governing biochar performance. To address existing knowledge gaps, we comprehensively evaluate recent available literature on biochar-based environmental remediation, focusing on key indicators of agricultural sustainability, including nutrients availability, soil biological activity, climate change mitigation, biochar-assisted phytostabilization, and crop productivity. Current evidence indicates that biochar application can achieve a net negative carbon footprint, mitigate greenhouse gas emissions and heavy metal contamination, and improve soil structure, fertility, and overall crop productivity on sustainable-basis. However, these benefits largely depend upon the various important biochar production factors including feedstock source, pyrolysis temperature, biochar stability, residence time, rate of application, and soil pH. Beyond its function as a soil amendment, biochar also serves as a multifunctional resource contributing to bioenergy production, waste reduction, and long-term carbon sequestration. At the same time, this review identifies critical research gaps, including the long-term field performance of biochar, mechanisms underlying the interactions between biochar and agronomic practices, and the environmental and human health risks associated with large-scale agricultural applications. Overall, this work highlights the importance of feedstock selection and pyrolysis parameters in designing biochar for environmental remediation and outlines future research directions to refine biochar engineering, application guidelines, and risk assessment frameworks for its sustainable use.
To alleviate the cadmium (Cd) stress in maize, we investigated the effects of intercropping maize with the Cd-hyperaccumulator plant Solanum nigrum var. humile on the growth and Cd uptake of both plant species under Cd stress (5 mg/L). Intercropping maize with S. nigrum var. humile increased the plant height, root length, and biomass in both plant species. Compared with their respective monocultures, intercropped maize showed the increase effects in root and shoot biomass by 13.58% and 8.58%, respectively, while intercropped S. nigrum var. humile exhibited the increases of 13.87% and 12.26%, respectively. Additionally, intercropping enhanced the photosynthetic pigment content, photosynthetic gas exchange parameters, and antioxidant enzyme activities in both plant species. Furthermore, intercropping with S. nigrum var. humile decreased the root Cd content but increased the shoot Cd content and translocation factor in maize. In S. nigrum var. humile, intercropping increased both root and shoot Cd contents, as well as the translocation factor. Thus, intercropping maize with S. nigrum var. humile can promote Cd uptake in aboveground parts of maize, and it may be not suitable for maize production in Cd-contaminated areas.
Nanotechnology has been established as a promising approach to improve heavy metal stress tolerance in horticultural crops. Melatonin (MT) is an emerging biostimulant for inducing stress resistance in plants. In this study, we evaluated the individual and combined effects of silicon nanoparticles (SiNPs; 50 mg L-1) and MT (25 mg L-1) on ornamental pepper (Capsicum annuum L., cv. Aladdin) grown in Cd-spiked soil (50 mg Cd kg-1). Morpho-physiological traits (biomass, photosynthetic pigments, leaf gas exchange, and Cd concentration), biochemical traits (proline, soluble sugars, electrolyte leakage, malondialdehyde, hydrogen peroxide, and superoxide), antioxidant enzyme activities, and the expression of defense genes were analyzed. Cd stress induced oxidative damage, inhibited photosynthesis-related parameters, and suppressed plant growth. Application of SiNPs and MT reduced tissue Cd accumulation, sustained photosynthesis, and improved plant growth, with the combined treatment showing the strongest overall mitigation. These improvements were associated with lower electrolyte leakage, hydrogen peroxide, superoxide, and malondialdehyde levels, together with higher antioxidant enzyme activities and defense-gene expression. The results support a combined Cd-stress mitigation in ornamental pepper; however, the study does not demonstrate soil Cd immobilization or statistically verified synergy. Further dose-response, long-term, and molecular experiments are mandatory to elucidate the interaction between SiNPs and MT under Cd stress.
This study evaluated the potential of Protaetia brevitarsis frass as an organic amendment for the safe cultivation of Scutellaria baicalensis in Cr-As-contaminated soil. A greenhouse pot experiment was conducted with five frass application gradients (CK, LD, MD, HD, and VHD) to assess rhizosphere properties, plant growth, and metal accumulation risk. Frass application improved soil water status, nutrient supply, and microbial biomass, but VHD markedly increased electrical conductivity, indicating a potential salinity risk. Plant growth showed a dose-dependent tradeoff: HD favored root development and leaf physiological activity, whereas VHD promoted shoot growth but reduced root allocation. The frass was rich in alkali-hydrolyzable nitrogen and available phosphorus, suggesting that soil N and P increases resulted from both direct nutrient input and rhizosphere transformation. Frass treatments generally reduced Cr and As accumulation in S. baicalensis, although responses varied between metals and application rates. Redundancy analysis identified alkali-hydrolyzable nitrogen as the major explanatory factor (82.6%). Because metal fractions were not determined, BCF was interpreted as an uptake-risk indicator rather than direct evidence of soil passivation. HD is recommended under the present pot conditions.
A randomized block experiment was conducted to investigate combined effects of planting density and biostimulants on sorghum performance and saline-alkali soil properties. Treatments included two densities (S, C) and three biostimulant applications: CK (control), sole γ-aminobutyric acid (T1), and γ-aminobutyric acid plus microbial inoculants (T2). The findings demonstrated that density-biostimulant interactions significantly affected sorghum agronomic traits and soil physicochemical properties. CT2 reduced soil pH, electrical conductivity by 18.30%, and bulk density by 16.46%, while increasing soil organic matter by 19%. Soil enzyme (N-acetyl-β-D-glucosaminidase, β-glucosidase, Leucine aminopeptidase, Alkaline phosphatase) activities showed distinct temporal dynamics: CT2 peaked at grain filling, whereas CK dominated at maturity stage. Furthermore, compared with CK, CT2 markedly increased plant height by 18.99%, stem diameter by 35.10%, leaf area by 67.49%, total dry matter by 25.86%, and dry matter partitioning to spikes by 37.03%. It also raised thousand-kernel weight by 33.49% and grains per spike by 51.65%, thereby improving grain yield by 6.00%. By comparison, ST1 yielded a striking 55.02% increment in grain yield. Altogether, these findings implied that under saline-alkali stress, dual biostimulants at low density benefit soil and single plants, and γ-aminobutyric acid at high density boosts population yield, showing individual-population yield tradeoffs.
Cadmium (Cd) accumulation in plants poses a serious risk to crop growth and human health. Although rhizobacteria are known to enhance plant Cd tolerance, research on rhizobacterial consortium to alleviate Cd toxicity in crops under hydroponic conditions remains limited. Two rhizobacterial strains, Bacillus cereus TLMC1 and Pseudomonas putida TLMC5, exhibiting high Cd tolerance and strong plant growth-promoting (PGP) traits, were selected to investigate their synergistic effects on Artemisia selengensis Turcz under Cd stress. Single and co-inoculation significantly decreased shoot Cd content and increased root Cd content, with co-inoculation yielding the lowest Cd translocation factors (0.08 and 0.09 under 1 and 10 mg L-1 Cd stress, respectively). Co-inoculation maximally reduced SOD and POD activities by 27.52% and 20.34% under 1 mg L-1 Cd stress. Soluble sugars, soluble proteins, vitamin C, and total flavonoids in edible shoots were all elevated, with co-inoculation showing optimal performance. Despite the reduction of Target Hazard Quotient (THQ) after inoculation, the minimum value remained above the safety threshold. These findings demonstrated that TLMC1 and TLMC5 co-inoculation effectively reduced Cd uptake and enriched nutritional and active components in the edible parts of A. selengensis, offering a preliminary microbial strategy for Cd risk mitigation in moderately Cd-polluted regions.
Arsenic (As) contamination poses a serious threat to crop productivity because of its high toxicity and accumulation in plants. This study investigated the protective effects of selenium (Se) against arsenic-induced toxicity in maize (Zea mays L.). Maize plants were treated with arsenic (150 µM), selenium (25 and 50 µM), and their combination (150 µM As + 25 µM Se). Growth parameters, oxidative stress markers, antioxidant enzyme activities, phenolic compound profiles, and elemental accumulation were evaluated. Arsenic significantly inhibited shoot and root growth, whereas supplementation with 25 µM Se increased shoot and root biomass by 15% and 48%, respectively, compared with arsenic treatment alone. Arsenic stress increased malondialdehyde (MDA) content by 107%, while 25 µM Se reduced this increase by 22%, indicating alleviation of oxidative damage. Selenium supplementation also reduced arsenic accumulation by 24% in shoots and 37% in roots. In addition, chlorogenic acid increased following selenium application, whereas several other phenolic compounds decreased under arsenic stress. Overall, 25 µM selenium mitigated arsenic toxicity by reducing oxidative damage and arsenic accumulation and was associated with improved antioxidant responses and changes in phenolic metabolism, suggesting its potential for alleviating arsenic-induced stress in maize.
CONTEXT:In arid environments such as Jordan, greywater treatment and recycling should be decentralized for better water resource management. OBJECTIVE:This study tests a lab-scale Horizontal Flow Constructed Wetland (HFCW) using locally supplied natural zeolite (Aritayn region) as a substrate and Cyperus alternifolius (Umbrella Sedge) as a phytoremediator. METHODOLOGY:Four parallel reactors (M1-M4) were used in a one-year mesocosm experiment to compare zeolite substrate and vegetation treatment effects. Effluent quality was tested for compliance with Jordanian water reuse requirements (JS 893:2021) in an intermittent flow regime with a constant hydraulic retention time (HRT) of roughly 5 days. RESULTS:The vegetated system (M2) reduced COD and BOD5 more efficiently than the unplanted zeolite-only control (M4), with 75.2% and 65.5%, respectively. M2 disinfection eliminated 95.4% E. coli, meeting national raw vegetable irrigation criteria. Maintaining physicochemical stability, pH (6.71) and TDS (<378 mg/L) within permissible values prevented soil salinization. Greywater-fed Cyperus alternifolius grew to 84.4 cm but had high proline (1.567) and osmotic stress (54.9% RWC). CONCLUSION:HFCWs containing local zeolite and Cyperus alternifolius represent a promising preliminary step for producing safe agricultural and landscape irrigation water efficiently and cheaply. However, remaining turbidity suggests a subsequent cleaning procedure for high-purity indoor reuse.
Crystal violet (CV) is a highly soluble dye used extensively in the textile industry and healthcare. The environmental complex structures of CV result in destructive effects on humans, animals, and the environment. In this study, adsorption of CV using Embelia schimperi biochar as an adsorbent was investigated. E. schimperi waste has unique structural properties and can be used as a biochar and utilized as a low-cost adsorbent. The experiments were two-tier designed: both the classical and optimization by response surface methodology (RSM). Three parameters were evaluated, which are adsorbent dosage, contact time, and pH, while the responses in this study are CV removal (%). Optimization studies were performed using RSM central composite Design using Minitab 17. A quadratic model was chosen for the response. The correlation coefficient, R2, for the quadratic model of CV removal (%) was 0.98, and the p < 0.0001. The optimum CV removal (%) predicted was found at 98%, by using 0.11 g of adsorbent dosage, 60 min of contact time, and pH of 7.5 at desirability of 1.0. It was concluded that the spent E. schimperi biochar can be used as an effective adsorbent for CV removal from aqueous solution.
Hexavalent chromium [Cr(VI)], released from tanning, electroplating, and metallurgical industries, is a Group 1 human carcinogen that induces severe oxidative stress in plants through excessive reactive oxygen species (ROS) production, disrupting antioxidant defence and causing damage to lipids, proteins, and DNA, ultimately reducing growth and productivity. This review synthesizes evidence from Google Scholar, Web of Science, Scopus, and ScienceDirect, emphasizing publications from 2020 onwards, covering Cr(VI)-induced oxidative stress, molecular alterations, PGPR mechanisms, phytohormone cross-talk, and multi-omics and synthetic biology approaches. Three core conclusions emerge: the ACC deaminase AP2/ERF pathway is the best-characterized PGPR-mediated Cr(VI) tolerance route, linking bacterial enzyme activity to plant transcriptional reprogramming and physiological recovery. No single phytohormone addresses all stress dimensions simultaneously, making complementary combinations like GA3 with IAA-producing PGPR, ABA with cytokinin, and JA with ACC deaminase strains more effective than single-hormone strategies. Finally, Cr(VI) molecular responses are governed by a four-module gene network coordinating uptake restriction, antioxidant defence, vacuolar sequestration, and transcriptional regulation. Two critical unresolved issues remain: the phytoextraction-food safety conflict, where PGPR traits enhancing soil Cr removal also increase shoot Cr translocation in food crops. Secondly, the absence of field-scale validation makes all current effectiveness metrics laboratory estimates, requiring multi-season agronomic confirmation.
In this study, the biostimulant potential of titanium dioxide (TiO2) nanoparticles was investigated to enhance sugar beet (Beta vulgaris L.) seed response to salt stress. Controlled applications were conducted at different NaCl (0-200 mM) and TiO2 (0-1,800 ppm) levels, and eight key morphological and physiological parameters were evaluated. In the first stage, the individual and interactive effects of the factors were examined using a two-way analysis of variance. Then, various machine learning-based regression models, primarily the Gradient Boosting algorithm, were used to numerically model plant responses. Based on the high-accuracy models, optimal application combinations were determined for each parameter and visualized using graphical surface analyses. Additionally, the most suitable overall TiO2 dosage for each salt level was calculated using a multi-criteria scoring system that assigned equal weight to all parameters. The results revealed that TiO2 exerts a regulatory and protective effect on plants against salt stress, with this effect varying with both dosage level and environmental stress severity. The study demonstrates that nanotechnological initiatives can be integrated into data-driven agricultural strategies to optimize stress management.
The accumulation of Cadmium (Cd) and microplastics (MPs) in agricultural soils poses a serious threat to plant growth, crop productivity, and food safety. This study investigates the combined effect of Cd and MPs on growth, antioxidant enzymes, and lipid peroxidation of Raphanus sativus, as well as the potential of Zinc oxide nanoparticles (ZnO NPs) in alleviating the combined Cd and MPs stress. Seeds were primed with different doses of ZnO NPs (40, 80, and 160 mg L-1). The findings depicted that MPs and Cd significantly reduced the growth attributes and photosynthetic pigments, while increasing the oxidative stress markers, biochemical content, and antioxidant activity in R. sativus. In contrast, ZnO NPs application improved growth attributes, photosynthetic efficiency, and antioxidant enzymes activity of R. sativus. Seed priming with ZnO NPs (160 mg L-1) showed significant improvement in growth and physiological attributes while reducing oxidative stress and Cd accumulation in radish plant tissues. These findings indicate that ZnO NPs application enhances plant tolerance to combined Cd and MP stress by improving the antioxidant defense system and reducing Cd uptake. Therefore, ZnO NPs seed priming represents a promising strategy for enhancing crop resilience and promoting sustainable agricultural practices in multi-contaminated soil.
Escalating land degradation challenges have led to active soil restoration programs in India to achieve land degradation neutrality by 2030. This study evaluates the phytoremediation potential of Calotropis procera for rehabilitating heavy metal (HM)-contaminated soils at an urban waste-dumping site over two years. Significant improvements in soil physicochemical properties were recorded, with bulk density and electrical conductivity decreasing by ∼1.3-fold and ∼3.7-fold, respectively, indicating reduced compaction and salinity stress. Increased organic carbon by ∼4.7-fold, cation exchange capacity by ∼35%, and NPK by ∼3- to 4-fold reflected improved soil fertility. The soil pollution index declined from severe/high levels to moderate/low levels, with maximum reduction in HMs Cd, Pb, and Cu. Bioaccumulation factor and translocation factor for Cd, Cr, and Ni in roots indicate strong phytostabilization, minimal leaching, and prevention from food chain transfer, whereas higher accumulation of Cu, Zn, and Pb in shoots reflects efficient phytoextraction. The progressive increase in bioaccumulation factors, particularly for Cd (∼4-fold) and Pb (∼3-fold), along with sustained metal uptake for 6-24 months, highlights long-term remediation efficiency. MAI and CBCI indices further validate the detoxification capacity of Calotropis procera, proving it thus to be an effective, non-edible phytoremediator for sustainable reclamation of metal-contaminated soils.
