Muhammad Usman

Excessive application of chemical fertilizers has reduced agricultural yield and final product quality because of several adverse environmental effects. The increasing demand for sustainable agricultural practices requires novel approaches to improve crop yield while reducing environmental impact. This study examined the effects of Leonardite and Arbuscular Mycorrhizal Fungi (AMF), on the metabolite profile and sugar metabolism of sunflower grains. The research was conducted during the 2024 and 2025 growing seasons to evaluate the effects of bio-organic treatments and minimal chemical fertilizer application on sunflower. The combined use of AMF and Leonardite significantly improved the metabolic profile of the grains, resulting in substantial increases in saturated fatty acids by 139.29%, total amino acids by 39.33%, and total sugars by 17.20%, although unsaturated fatty acids showed a slight reduction of 9.47%. Changes in primary metabolites, including fatty acids and amino acids, are important for human nutrition and metabolic processes. The treatments also promoted the accumulation of secondary metabolites, including lipid soluble and water-soluble antioxidants, which play a crucial role in enhancing the antioxidant potential of the grains. The combined application of AMF and Leonardite also increased the elemental composition of the grains, particularly phosphorus and potassium levels. Our findings indicate that the combination of Leonardite and AMF greatly improves the nutritional quality and metabolic profile of sunflower grains. This environmentally sustainable approach offers a viable way to enhance sunflower yield, improve food safety, and support ecological wellbeing by reducing dependence on chemical fertilizers. Further research on plant soil interactions and bio-organic fertilizers across different plant species, along with fundamental molecular, biochemical, and physiological studies, is still needed.

Mercury (Hg) contamination in agricultural soils threatens crop productivity and ecosystem sustainability. This study investigates the synergistic effects of Pieris japonica-derived biochar and the Hg-resistant bacterium Bacillus cereus B2 in mitigating Hg toxicity in sorghum (Sorghum bicolor L.) grown in Hg-contaminated soils (0, 15, 20, and 25 mg Hg kg⁻¹). Hg stress significantly inhibited plant growth, gas exchange, and photosynthetic pigments, with the greatest reductions at 25 mg kg⁻¹ Hg. The combined application of biochar (4%) and B. cereus B2 notably enhanced plant height (34.7%), stomatal conductance (50.1%), photosynthetic rate (24.5%), transpiration rate (60.2%), water-use efficiency (24.5%), chlorophyll a (75.8%), chlorophyll b (29.3%), carotenoids (27.0%), and total chlorophyll (59.5%) compared to individual treatments. This synergistic approach also stimulated antioxidant defenses, increasing activities of ascorbate peroxidase (20.1%), catalase (25.2%), superoxide dismutase (34.9%), and peroxidase (49.7%), while reducing reactive oxygen species (H₂O₂ and O₂⁻) and lipid peroxidation (MDA). Furthermore, Hg accumulation in sorghum roots and shoots was significantly reduced under the combined treatment, indicating lower Hg bioavailability. These findings demonstrate the novel synergistic potential of P. japonica biochar and B. cereus B2 in enhancing Hg immobilization, improving plant physiological resilience, and strengthening antioxidant defenses in sorghum, providing an effective and sustainable strategy for Hg-contaminated soil remediation. Graphical abstract The alternative text for this image may have been generated using AI.

Extensive soil contamination with polycyclic aromatic hydrocarbons (PAHs), particularly naphthalene and benzo(a)pyrene, poses serious threats to agricultural productivity and ecological health. This study aimed to evaluate the synergistic effects of foliar-applied selenium nanoparticles (SeNP) and aged cellulose-derived biochar (CBC) on PAH immobilization and spinach growth in contaminated soils. A controlled pot experiment was conducted, and comparative analysis among treatments was performed using adsorption isotherm modelling, physicochemical characterization of biochar (FTIR and mineral phase analysis), PAH quantification by GC–MS, elemental analysis by ICP-OES, and statistical evaluation of plant physiological and biochemical parameters. Results revealed that aging of CBC enhanced surface functional group formation and transformed mineral phases from Mg₂SiO₄ and MgO to more stable forms such as MgCO₃, Ca, and SiO₂. During PAH adsorption, the relative contribution of mineral components decreased while non-mineral functional groups played a dominant role, reflected by a shift from Freundlich to Langmuir isotherm behavior. The combined application of foliar SeNP and aged CBC significantly improved antioxidant enzyme activities, photosynthetic performance, and PAH sequestration in root cell walls and vacuoles, thereby reducing naphthalene and benzo(a)pyrene uptake and toxicity. Overall, the integrated strategy of SeNP and aged CBC demonstrated enhanced PAH immobilization and improved plant resilience, providing a sustainable approach for remediation of contaminated agricultural soils and protection of food security. Graphical Abstract

Cadmium (Cd) soil contamination is a worldwide concern. Biochar, produced from organic waste, can improve soil quality in polluted areas. The present studies investigated the impact of biochar on cadmium uptake, biochemical and morpho-physiological parameters of Ocimum basilicum L. leaves under cadmium stress. A Pot study was conducted using a factorial experiment fitted into complete randomized design. This experimental design included three biochar treatments (control, 1%, and 2% of 2.5 kg soil) and three cadmium concentrations (0, 25, and 50 mg/kg soil), with five replications for each condition. This study's findings indicate that biochar application positively influenced morphological traits, relative water content, photosynthetic pigments, and catalase activity of O. basilicum plants subjected to cadmium stress. Additionally, application of biochar led to a reduction in total soluble sugars (23%), antioxidant activity (26%), total phenolic content, proline levels, soluble protein concentrations, electrolyte leakage, guaiacol peroxidase, and ascorbate peroxidase activities, as well as cadmium levels and target hazard quotient (THQ). Biochar use led to a reduction in THQ across all cadmium treatments. When the level of cadmium was at its highest (50 mg/kg), 2% biochar addition resulted in a 29.93% reduction in THQ compared to the treatment without biochar treatment. This study offers pragmatic options for amendment of contaminated soils, the augmentation of crop productivity, and the assurance of safe herb production. The integration of eco-friendly biochar technology with medicinal crop management connects agronomy, environmental science, and amendment, providing scalable options for sustainable agriculture.

Two independent experiments were performed to investigate role of NO in 5-aminolevulinic acid-mediated resistance to lead toxicity in barley plants. Lead toxicity significantly resulted in reduction of plant growth, Fv/Fm, total chlorophyll, leaf water potential, and Ca²⁺ as well as K⁺ potassium levels. Concurrently, it resulted in elevated levels of leaf MDA, H₂O₂, EL, Pb, and NO in comparison to control group. Both ALA (50 µM and 100 µM; ALA1 and ALA2) treatments enhanced plant growth parameters and elevated leaf K⁺ and Ca²⁺ levels, while simultaneously decreasing leaf Pb, H₂O₂, and MDA concentrations in comparison to Pb-stressed plants. A second experiment was conducted to ascertain involvement of nitric oxide in mitigation of Pb stress in barley seedlings by ALA, utilizing nitric oxide scavenger C₁₄H₁₆N₂O₄.K (cPTIO) in conjunction with ALA treatments. ALA-induced tolerance to Pb stress was entirely negated by administration of cPTIO (C₁₄H₁₆N₂O₄.K), which significantly decreased concentrations of endogenous nitric oxide. The findings indicated that ALA improved resistance of barley seedlings to Pb toxicity via activating endogenous nitric oxide. This was corroborated by elevation of H₂O₂ and MDA levels, with a reduction in SOD, CAT, and POD activities. The application of cPTIO along with ALA, led to growth inhibition and a notable increase in leaf Pb concentrations. Both ALA and nitric oxide collaboratively enhanced Pb tolerance in barley.