Iron oxide nanoparticles alleviate arsenic phytotoxicity in rice by improving iron uptake, oxidative stress tolerance and diminishing arsenic accumulation

Effect of nanocellulose-assisted green-synthesized iron nanoparticles and conventional sources of Fe on pot marigold plants symbiotically with arbuscular mycorrhizal fungus (Funneliformis mosseae)

The objective of this study was to investigate the effect of nanocellulose-assisted green-synthesized iron nanoparticles (FeNPs) and conventional sources of Fe on pot marigold (Calendula officinalis L.) plants symbiotically with arbuscular mycorrhizal (AM). Pot marigold plants were inoculated with Funneliformis mosseae in addition to applying ferrous sulfate, FeNPs, and Fe-EDDHA at a rate of 10 mg Fe/kg soil, which follows the recommended rates of fertilizer. Their effects on plant growth, morphology, and physiological parameters were to be compared in the experiment. According to the findings, FeNPs significantly increased plant height, mean stem length, flower number, and total flower lifespan, especially when used with AMF. Most notably, this treatment produced the highest total chlorophyll content (6.62 mg/g FW), active iron in leaves (10 µg/g FW), essential oil (5.75%), mean number of leaves per plant (26.25), number of flowers per plant (6.5), and overall flower lifespan (92.75 days). It also produced superior mycorrhizal root colonization (52.47%). However, because of its lower uptake efficiency and rapid oxidation, ferrous sulfate showed limited performance. By enhancing iron bioavailability, the FeNPs promoted more effective metabolic activity and nutrient absorption. These results demonstrate the advantage of producing FeNPs as a bio-sustainable and biocompatible alternative for synthetic chelates, thus providing an interesting way to improve crop growth promotion in mycorrhizal cropping systems.

Unseen threats in aquatic and terrestrial ecosystems: Nanoparticle persistence, transport and toxicity in natural environments

Although nanoparticles (NPs) are increasingly used in various industries, their uncontrolled environmental release presents a potential risk to water bodies, vegetation and human health. Although previous review studies evaluated the toxicity and bioaccumulation of NPs, their long-term ecological impacts and transport dynamics in aquatic and terrestrial systems remain unexplored. The current review examined the mechanistic bioaccumulation, transport and environmental persistence of NPs, highlighting the need for concurrent risk assessment, regulation and management strategies. The multifaceted nature of nanotechnology necessitates a balanced approach considering both the benefits of NPs and their potential environmental and health risks, requiring comprehensive risk assessment and management strategies. The complexities of NPs risk assessment, emphasizing the unique properties of NPs influencing their toxicity and environmental behavior are critically addressed. Strategies to mitigate NPs' environmental impact include advanced monitoring techniques, regulatory frameworks tailored to NPs' unique properties, promotion of green nanotechnology practices, and NP remediation technologies. Given the complexity and uncertainty surrounding NPs, integration of regulatory, technological, and research-based strategies is imperative. This involves detailed NPs characterization techniques providing basic data for environmental fate prediction models and understanding of biologically relevant risk assessment models to safeguard our environment and public health. In this study, the recent advances in NPs persistence, environmental transport modelling and toxicity mechanisms are uniquely integrated, providing a framework to ecological risk assessment and regulatory approaches.

Nanotechnology in Plant Nanobionics: Mechanisms, Applications, and Future Perspectives

Plants are vital to ecosystems and human survival, possessing intricate internal and inter-plant signaling networks that allow them to adapt quickly to changing environments and maintain ecological balance. The integration of engineered nanomaterials (ENMs) with plant systems has led to the emergence of plant nanobionics, a field that holds the potential to enhance plant capabilities significantly. This integration may result in improved photosynthesis, increased nutrient uptake, and accelerated growth and development. Plants treated with ENMs can be stress mitigators, pollutant detectors, environmental sensors, and even light emitters. This review explores recent advancements in plant nanobionics, focusing on nanoparticle (NP) synthesis, adhesion, uptake, transport, fate, and application in enhancing plant physiological functioning, stress mitigation, plant health monitoring, energy production, environmental sensing, and overall plant growth and productivity. Potential research directions and challenges in plant nanobionics are highlighted, and how material optimization and innovation are propelling the growth in the field of smart agriculture, pollution remediation, and energy/biomass production are discussed.

Safe Production of Rice (Oryza sativa L.) in Arsenic-Contaminated Soil: a Remedial Strategy using Micro-Nanostructured Bone Biochar

This study investigated the effects of fine-sized pork bone biochar particles on remediating As-contaminated soil and alleviating associated phytotoxicity to rice in 50-day short-term and 120-day full-life-cycle pot experiments. The addition of micro-nanostructured pork bone biochar (BC) pyrolyzed at 400 and 600 °C (BC400 and BC600) significantly increased the As-treated shoot and root fresh weight by 24.4-77.6%, while simultaneously reducing tissue As accumulation by 26.7-64.1% and increasing soil As content by 17.1-27.1% as compared to As treatment. Microbial community analysis demonstrated that BC600 and BC400 treatments increased the proportion of plant growth-promoting microbes such as Ceratobasidium and Achromobacter by 33-81.6% in the roots and As adsorption-associated Bacillus by 1.15-1.59-fold in the rhizosphere soil. Metabolomic profiling suggests that BC and As coexposure triggered differentially expressed metabolites (DEMs) enriched in lipid, carbohydrate, and amino acid metabolic pathways, all of which could alleviate As-induced phytotoxicity and promote plant As tolerance. Importantly, the quality of As-treated rice grains was improved by the BC amendments. This study demonstrates the significant potential of BC for enhancing crop growth and minimizing the As-induced phytotoxicity to rice and provides a framework for a promising strategy for remediating heavy metal(loid)-contaminated soil while simultaneously promoting food safety.

Nanoparticles as catalysts of agricultural revolution: enhancing crop tolerance to abiotic stress: a review

Ensuring global food security and achieving sustainable agricultural productivity remains one of the foremost challenges of the contemporary era. The increasing impacts of climate change and environmental stressors like drought, salinity, and heavy metal (HM) toxicity threaten crop productivity worldwide. Addressing these challenges demands the development of innovative technologies that can increase food production, reduce environmental impacts, and bolster the resilience of agroecosystems against climate variation. Nanotechnology, particularly the application of nanoparticles (NPs), represents an innovative approach to strengthen crop resilience and enhance the sustainability of agriculture. NPs have special physicochemical properties, including a high surface-area-to-volume ratio and the ability to penetrate plant tissues, which enhances nutrient uptake, stress resistance, and photosynthetic efficiency. This review paper explores how abiotic stressors impact crops and the role of NPs in bolstering crop resistance to these challenges. The main emphasis is on the potential of NPs potential to boost plant stress tolerance by triggering the plant defense mechanisms, improving growth under stress, and increasing agricultural yield. NPs have demonstrated potential in addressing key agricultural challenges, such as nutrient leaching, declining soil fertility, and reduced crop yield due to poor water management. However, applying NPs must consider regulatory and environmental concerns, including soil accumulation, toxicity to non-target organisms, and consumer perceptions of NP-enhanced products. To mitigate land and water impacts, NPs should be integrated with precision agriculture technologies, allowing targeted application of nano-fertilizers and nano-pesticides. Although further research is necessary to assess their advantages and address concerns, NPs present a promising and cost-effective approach for enhancing food security in the future.

Boosting Rice Resilience: Role of Biogenic Nanosilica in Reducing Arsenic Toxicity and Defending against Herbivore

The use of nanoparticles is a promising ecofriendly strategy for mitigating both abiotic and biotic stresses. However, the physiological and defense response mechanisms of plants exposed to multiple stresses remain largely unexplored. Herein, we examined how foliar application of biogenic nanosilica (BNS) impacts rice plant growth, molecular defenses, and metabolic responses when subjected to arsenic (As) toxicity and infested by the insect Chilo suppressalis. We show that BNS significantly increased shoot and root silicon accumulation but reduced the shoot As content by 34.7% under herbivory. Additionally, BNS reduced C. suppressalis larval weight gain by 34.5 and 12.3% without and with As stress, respectively. Importantly, BNS enhanced antioxidant enzyme activity under As stress, herbivore attack, and combined pressures, surpassing the effects of traditional silicate fertilizers. BNS ultimately increased rice shoot biomass by 8.2-23.4% under the respective stress conditions compared to the control treatment. Moreover, while As stress alone diminished the plant's resistance to herbivores, BNS application countered this effect by increasing detoxifying compound (e.g., glutathione) production and antioxidant enzyme activity. This study highlights the impact of biotic and abiotic stress interactions on BNS-enhanced plant resilience mechanisms in rice plants, reallocating resources to counter heavy metal toxicity and herbivore damage in agroecosystems.

Green synthesized FeNPs ameliorate drought stress in Spinacia oleracea L. through improved photosynthetic capacity, redox balance, and antioxidant defense

The present study was designed to highlight the ameliorative role of iron nanoparticles (FeNPs) against drought stress in spinach (Spinacia oleracea L.) plants. A pot experiment was performed in two-way completely randomize design with three replicates. For drought stress three levels were used by maintaining field capacity of the soil. This included control (100% field capacity), moderate drought stress (D1; 50% field capacity) and severe drought stress (D2; 25% field capacity). FeNPs synthesized by green method using rice straw were applied along with precursor FeCl3, used as Fe source for the synthesis of FeNPs, through foliar spray (40 mg L- 1 for both). Growth parameters, efficiency of photosynthetic machinery, gas exchange attributes, total soluble proteins, and inorganic ions (Ca2+, K+ & Fe2+) were significantly reduced at both D1 and D2 stress levels, compared to control plants. Fe supplements in the form of FeCl3 and FeNPs improved these attributes in both control and drought conditions. Malondialdehyde, H2O2, relative membrane permeability (stress indicators) and the activities of antioxidants were increased in response to drought stress. Fe supplements further improved the antioxidant defense activities and efficiently lowered the effects of stress indicators. These effects of FeCl3 and FeNPs resulted in improved growth of S. oleracea plants in control and drought conditions. Results showed that FeNPs had more prominent effects on growth of S. oleracea plants compared to FeCl3. These findings suggest that FeNPs could be a helpful tool for lessening the harmful consequences of drought stress and this can be used for abiotic stress alleviation in other crops as well.

Nano-sized metal oxide fertilizers for sustainable agriculture: balancing benefits, risks, and risk management strategies

This critical review comprehensively analyses nano-sized metal oxide fertilizers (NMOFs) and their transformative potential in sustainable agriculture. It examines the characteristics and benefits of different NMOFs, such as zinc, copper, iron, magnesium, manganese, nickel, calcium, titanium, cerium, and silicon oxide nanoparticles. NMOFs offer unique advantages such as increased reactivity, controlled-release mechanisms, and targeted nutrient delivery to address micronutrient deficiencies, enhance crop resilience, and improve nutrient efficiency. The review underscores the essential role of micronutrients in plant metabolism, crop growth, and ecosystem health, highlighting their importance alongside macronutrients. NMOFs present significant benefits over traditional fertilizers, including enhanced plant uptake, reduced nutrient losses, and decreased environmental impact. However, the review also critically examines potential risks associated with NMOFs, such as nanoparticle toxicity and environmental persistence. A comparative analysis of different metal types used in nanofertilizers is provided, detailing their primary advantages and potential drawbacks. The review emphasizes the need for cautious management of NMOFs to ensure their safe and effective use in agriculture. It calls for comprehensive research to understand the long-term effects of NMOFs on plant health, soil ecosystems, and human health. By integrating insights from material science, plant biology, and environmental science, this review offers a holistic perspective on the potential of NMOFs to address global food security challenges amid resource constraints and climate change. The study concludes by outlining future research directions and advocating for interdisciplinary collaboration to advance sustainable agricultural practices and optimize the benefits of NMOFs.

Seed priming with Fe3O4-SiO2 nanocomposites simultaneously mitigate Cd and Cr stress in spinach (Spinacia oleracea L.): A way forward for sustainable environmental management

Seed priming with a composite of iron oxide (Fe3O4) and silicon dioxide (SiO2) nanoparticles (NPs) is an innovative technique to mitigate cadmium (Cd) and chromium (Cr) uptake in plants from rooting media. The current study explored the impact of seed priming with varying levels of Fe3O4 NPs, SiO2 NPs, and Fe3O4-SiO2 nanocomposites on Cd and Cr absorption and phytotoxicity, metal-induced oxidative stress mitigation, growth and biomass yield of spinach (Spinacia oleracea L.). The results showed that seed priming with the optimum level of 100 mg L-1 of Fe3O4-SiO2 nanocomposites significantly (p ≤ 0.05) increased root dry weight (144 %), shoot dry weight (243 %) and leaf area (34.4 %) compared to the control, primarily by safeguarding plant's photosynthetic machinery, oxidative stress and phytotoxicity of metals. Plants treated with this highest level of Fe3O4-SiO2 nanocomposites exhibited a substantial increase in photosynthetic and gas exchange indices of spinach plants and enhanced activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) antioxidant enzymes by 45 %, 48 %, and 60 %, respectively. Correspondingly, the relative gene expression levels of SOD, CAT, and APX also rose by 109 %, 181 %, and 137 %, respectively, compared to non-primed plants. This nanocomposite application also boosted the levels of phenolics (28 %), ascorbic acid (68 %), total sugars (129 %), flavonoids (39 %), and anthocyanin (29 %) in spinach leaves, while significantly reducing Cd (34.7 %, 53.4 %) and Cr (20.2 %, 28.8 %) contents in plant roots and shoots, respectively. These findings suggest that seed priming with Fe3O4-SiO2 nanocomposites effectively mitigated the toxic effects of Cd and Cr, enhancing the growth and biomass yield of spinach in Cd and Cr co-contaminated environments, offering a promising sustainable approach for producing metal-free crops.

Biochar and nanoscale silicon synergistically alleviate arsenic toxicity and enhance productivity in chili peppers (Capsicum annuum L.)

Arsenic (As) contamination in agricultural soils threatens crop productivity and food safety. In this study, we examined the efficacy of biochar (BC) and silicon nanoparticles (SiNPs) as environmentally sustainable soil amendments to alleviate As toxicity in chili (Capsicum annuum L.) plants. Our findings revealed that As stress severely inhibited the growth parameters of Capsicum annuum L., and subsequently reduced yield. However, the application of BC and SiNPs into the contaminated soil significantly reversed these negative effects, promoting plant length and biomass, particularly when applied together in a synergistic manner. Arsenic stress led to increased oxidative damage, as evidenced by a 29% increase in leaf malondialdehyde content as compared to the healthy plants. Nevertheless, the synergistic (BC + SiNPs) application effectively modulated antioxidant enzyme activity, resulting in a remarkable 55% and 66% enhancement in the superoxide dismutase and catalase levels, respectively, boosting chili's resistance against oxidative stress. Similarly, BC + SiNPs amendments improved photosynthesis by 52%, stomatal conductance by 39%, soluble sugars by 42%, and proteins by 30% as compared with those of control treatment. Additionally, the combined BC + SiNPs application significantly reduced root As content by 61% and straw As by 37% as compared with the control one. Transmission electron microscopy confirmed that the synergistic use of BC and SiNPs preserved chili leaf ultrastructure, shielding against As-induced damage. Overall, the supplementation of contaminated soil with BC and SiNPs was proved to be a sustainable strategy for mitigating As toxicity in chili peppers, enhancing plant growth, physiology, and yield, and thereby food safety.

Nanomaterial-Based Biofortification: Potential Benefits and Impacts of Crops

Nanomaterials (NMs) have shown relevant impacts in crop protection, improvement of yields, and minimizing collateral side effects of fertilizer and pesticides in vegetable and fruit production. The application of NMs to improve biofortification has gained much attention in the last five years, offering a hopeful and optimistic outlook. Thus, we propose comprehensively revising the scientific literature about the use of NMs in the agronomic biofortification of crops and analyzing the beneficial impact of the use of NMs. The results indicated that different species of plants were biofortified with essential elements and macronutrients after the applications of Zn, Fe, Se, nanocomposites, and metalloid NPs. In addition, the physiological performances, antioxidant compounds, and yields were improved with NMs. Using nanofertilizers for the biofortification of crops can be considered a promising method to deliver micronutrients for plants with beneficial impacts on human health, the environment, and agriculture.

Metal oxide nanoparticles as a promising method to reduce biotic stress in plant cell wall: A review

The application of metal-based nanoparticles in inhibiting plant pathogenic bacteria and fungi has gained significant attention in recent years. several nanoparticles, including silver (Ag), titanium dioxide (TiO2), magnesium oxide (MgO), copper (Cu), and zinc oxide (ZnO), can generate reactive oxygen species (ROS) when exposed to light. The oxidative damage inflicted by ROS can disrupt the cellular structures and metabolic processes of pathogens, leading to their inactivation and inhibition. However, it is crucial to consider the potential environmental and health impacts of nanoparticle use. The safe and responsible use of nanoparticles and their potential risks should be thoroughly evaluated to ensure sustainable and effective plant disease management practices.

Green synthesized iron oxide nanoparticles as a potential regulator of callus growth, plant physiology, antioxidative and microbial contamination in Oryza sativa L

In tissue culture, efficient nutrient availability and effective control of callus contamination are crucial for successful plantlet regeneration. This study was aimed to enhance callogenesis, callus regeneration, control callus contamination, and substitute iron (Fe) source with FeO-NPs in Murashige and Skoog (MS) media. Nanogreen iron oxide (FeO-NPs) were synthesized and well characterized with sizes ranging from 2 to 7.5 nm. FeO-NPs as a supplement in MS media at 15 ppm, significantly controlled callus contamination by (80%). Results indicated that FeCl3-based FeO-NPs induced fast callus induction (72%) and regeneration (43%), in contrast FeSO4-based FeO-NPs resulted in increased callus weight (516%), diameter (300%), number of shoots (200%), and roots (114%). Modified media with FeO-NPs as the Fe source induced fast callogenesis and regeneration compared to normal MS media. FeO-NPs, when applied foliar spray, increased Plant fresh biomass by 133% and spike weight by 350%. Plant height increased by 54% and 33%, the number of spikes by 50% and 265%, and Chlorophyll content by 51% and 34% in IRRI-6 and Kissan Basmati, respectively. Additionally, APX (Ascorbate peroxidase), SOD (Superoxide dismutase), POD (peroxidase), and CAT (catalase) increased in IRRI-6 by 27%, 29%, 283%, 62%, while in Kissan Basmati, APX increased by 70%, SOD decreased by 28%, and POD and CAT increased by 89% and 98%, respectively. Finally, FeO-NPs effectively substituted Fe source in MS media, shorten the plant life cycle, and increase chlorophyll content as well as APX, SOD, POD, and CAT activities. This protocol is applicable for tissue culture in other cereal crops as well.

FeONPs alleviate cadmium toxicity in Solanum melongena through improved morpho-anatomical and physiological attributes, along with oxidative stress and antioxidant defense regulations

In this study, various constraints of Cd toxicity on growth, morpho-anatomical characters along with physiological and biochemical metabolic processes of Solanum melongena L. plants were analyzed. Conversely, ameliorative role of iron oxide nanoparticles (FeONPs) was examined against Cd stress. For this purpose, the following treatments were applied in completely randomized fashion; 3 mM CdCl2 solution applied with irrigation water, 40 and 80 ppm solutions of FeONPs applied via foliar spray. Regarding the results, Cd caused oxidative damage to plants' photosynthetic machinery, resulting in elevated levels of stress-markers like malondialdehyde (MDA), hydrogen peroxide (H2O2), and electrolytic leakage (EL) along with slight increase in antioxidants activities, including glutathione (GsH), ascorbate (AsA), catalases (CAT), peroxidases (POD), superoxide dismutase (SOD), and ascorbate peroxidases (APX). Also, high Cd level in plants disturb ions homeostasis and reduced essential minerals uptake, including Ca and K. This ultimately reduced growth and development of S. melongena plants. In contrast, FeONPs supplementations improved antioxidants (enzymatic and non-enzymatic) defenses which in turn limited ROS generation and lowered the oxidative damage to photosynthetic machinery. Furthermore, it maintained ionic balance resulting in enhanced uptake of Ca and K nutrients which are necessary for photosynthesis, hence also improved photosynthesis rate of S. melongena plants. Overall, FeONPs foliar spray effectively mitigated Cd toxicity imposed on S. melongena plants.

Arsenic-induced plant stress: Mitigation strategies and omics approaches to alleviate toxicity

Arsenic (As) is a metalloid pollutant that is extensively distributed in the biosphere. As is among the most prevalent and toxic elements in the environment; it induces adverse effects even at low concentrations. Due to its toxic nature and bioavailability, the presence of As in soil and water has prompted numerous agricultural, environmental, and health concerns. As accumulation is detrimental to plant growth, development, and productivity. Toxicity of As to plants is a function of As speciation, plant species, and soil properties. As inhibits root proliferation and reduces leaf number. It is associated with defoliation, reduced biomass, nutrient uptake, and photosynthesis, chlorophyll degradation, generation of reactive oxygen species, membrane damage, electrolyte leakage, lipid peroxidation and genotoxicity. Plants respond to As stress by upregulating genes involved in detoxification. Different species have adopted avoidance and tolerance responses for As detoxification. Plants also activate phytohormonal signaling to mitigate the stressful impacts of As. This review addresses As speciation, uptake, and accumulation by plants. It describes plant morpho-physiological, biochemical, and molecular changes and how phytohormones respond to As stress. The review closes with a discussion of omic approaches for alleviating As toxicity in plants.

Nano-Bioremediation of Arsenic and Its Effect on the Biological Activity and Growth of Maize Plants Grown in Highly Arsenic-Contaminated Soil

Arsenic (As)-contaminated soil reduces soil quality and leads to soil degradation, and traditional remediation strategies are expensive or typically produce hazardous by-products that have negative impacts on ecosystems. Therefore, this investigation attempts to assess the impact of As-tolerant bacterial isolates via a bacterial Rhizobim nepotum strain (B1), a bacterial Glutamicibacter halophytocola strain (B2), and MgO-NPs (N) and their combinations on the arsenic content, biological activity, and growth characteristics of maize plants cultivated in highly As-contaminated soil (300 mg As Kg-1). The results indicated that the spectroscopic characterization of MgO-NPs contained functional groups (e.g., Mg-O, OH, and Si-O-Si) and possessed a large surface area. Under As stress, its addition boosted the growth of plants, biomass, and chlorophyll levels while decreasing As uptake. Co-inoculation of R. nepotum and G. halophytocola had the highest significant values for chlorophyll content, soil organic matter (SOM), microbial biomass (MBC), dehydrogenase activity (DHA), and total number of bacteria compared to other treatments, which played an essential role in increasing maize growth. The addition of R. nepotum and G. halophytocola alone or in combination with MgO-NPs significantly decreased As uptake and increased the biological activity and growth characteristics of maize plants cultivated in highly arsenic-contaminated soil. Considering the results of this investigation, the combination of G. halophytocola with MgO-NPs can be used as a nanobioremediation strategy for remediating severely arsenic-contaminated soil and also improving the biological activity and growth parameters of maize plants.

Iron nanoparticles in combination with other conventional Fe sources remediate mercury toxicity-affected plants and soils by nutrient accumulation in bamboo species

The issue of mercury (Hg) toxicity has recently been identified as a significant environmental concern, with the potential to impede plant growth in forested and agricultural areas. Conversely, recent reports have indicated that Fe, may play a role in alleviating HM toxicity in plants. Therefore, this study's objective is to examine the potential of iron nanoparticles (Fe NPs) and various sources of Fe, particularly iron sulfate (Fe SO4 or Fe S) and iron-ethylene diamine tetra acetic acid (Fe - EDTA or Fe C), either individually or in combination, to mitigate the toxic effects of Hg on Pleioblastus pygmaeus. Involved mechanisms in the reduction of Hg toxicity in one-year bamboo species by Fe NPs, and by various Fe sources were introduced by a controlled greenhouse experiment. While 80 mg/L Hg significantly reduced plant growth and biomass (shoot dry weight (36%), root dry weight (31%), and shoot length (31%) and plant tolerance (34%) in comparison with control treatments, 60 mg/L Fe NPs and conventional sources of Fe increased proline accumulation (32%), antioxidant metabolism (21%), polyamines (114%), photosynthetic pigments (59%), as well as root dry weight (25%), and shoot dry weight (22%), and shoot length (22%). Fe NPs, Fe S, and Fe C in plant systems substantially enhanced tolerance to Hg toxicity (23%). This improvement was attributed to increased leaf-relative water content (39%), enhanced nutrient availability (50%), improved antioxidant capacity (34%), and reduced Hg translocation (6%) and accumulation (31%) in plant organs. Applying Fe NPs alone or in conjunction with a mixture of Fe C and Fe S can most efficiently improve bamboo plants' tolerance to Hg toxicity. The highest efficiency in increasing biochemical and physiological indexes under Hg, was related to the treatments of Fe NPs as well as Fe NPs + FeS + FeC. Thus, Fe NPs and other Fe sources might be effective options to remove toxicity from plants and soil. The future perspective may help establish mechanisms to regulate environmental toxicity and human health progressions.

Nanoparticles as a Tool for Alleviating Plant Stress: Mechanisms, Implications, and Challenges

Plants, being sessile, are continuously exposed to varietal environmental stressors, which consequently induce various bio-physiological changes in plants that hinder their growth and development. Oxidative stress is one of the undesirable consequences in plants triggered due to imbalance in their antioxidant defense system. Biochemical studies suggest that nanoparticles are known to affect the antioxidant system, photosynthesis, and DNA expression in plants. In addition, they are known to boost the capacity of antioxidant systems, thereby contributing to the tolerance of plants to oxidative stress. This review study attempts to present the overview of the role of nanoparticles in plant growth and development, especially emphasizing their role as antioxidants. Furthermore, the review delves into the intricate connections between nanoparticles and plant signaling pathways, highlighting their influence on gene expression and stress-responsive mechanisms. Finally, the implications of nanoparticle-assisted antioxidant strategies in sustainable agriculture, considering their potential to enhance crop yield, stress tolerance, and overall plant resilience, are discussed.

A novel approach for the green synthesis of iron nanoparticles using marigold extract, black liquor, and nanocellulose: Effect on marigold growth parameters

This study aimed to investigate a novel method for the green synthesis of iron nanoparticles (FeNPs) using marigold extract (Calendula officinalis L), kraft pulping black liquor, and nanocellulose. Then, the efficacy of FeNPs as a direct nanofertilizer on the growth parameters of marigold was investigated. Characterization techniques including FESEM, EDX, VSM, and FTIR were used to confirm the successful synthesis of FeNPs. The characterization results confirmed the formation and presence of FeNPs in the 20-100 nm range. FeNPs synthesized with nanocellulose notably enhanced marigold growth parameters compared to other materials. However, all nanoparticle variants, including those from marigold extract and black liquor, improved germination, plant height, root length, and plant dry weight compared to the control. Moreover, treatments exhibited higher available iron and total plant iron levels than the control. Thus, employing 10 mg FeNPs (prepared with 5.0 % nanocellulose) appears optimal for enhancing marigold growth and yield.

Zinc oxide application alleviates arsenic-mediated oxidative stress via physio-biochemical mechanism in rice

Arsenic (As) pollution in cultivated soils poses a significant risk to the sustainable growth of agriculture and jeopardizes food security. However, the mechanisms underlying how zinc (Zn) regulates the toxic effects induced by As in plants remain poorly understood. Hence, this study aimed to explore the potential of ZnO as an effective and environmentally friendly amendment to alleviate As toxicity in rice, thereby addressing the significant risk posed by As pollution in cultivated soils. Through a hydroponic experiment, the study assessed the mitigating effects of different ZnO dosages (Zn5, 5 mg L-1; Zn15, 15 mg L-1; Zn30, 30 mg L-1) on rice seedlings exposed to varying levels of As stress (As0, 0 µM L-1; As25, 25 µM L-1). The findings of the study demonstrate significant improvements in plant height and biomass (shoot and root), with a notable increase of 16-40% observed in the Zn15 treatment, and an even more substantial enhancement of 29-53% observed in the Zn30 treatment under As stress, compared to respective control treatment. Furthermore, in the Zn30 treatment, the shoot and root As contents substantially reduced by 47% and 63%, respectively, relative to the control treatment. The elevated Zn contents in shoots and roots enhanced antioxidant enzyme activities (POD, SOD, and CAT), and decreased MDA contents (13-25%) and H2O2 contents (11-27%), indicating the mitigation of oxidative stress. Moreover, the expression of antioxidant-related genes, OsSOD-Cu/Zn, OsCATA, OsCATB, and OsAPX1 was reduced when rice seedlings were exposed to As stress and significantly enhanced after Zn addition. Overall, the research suggests that ZnO application could effectively mitigate As uptake and toxicity in rice plants cultivated in As-contaminated soils, offering potential solutions for sustainable agriculture and food security.

Residual efficiency of iron-nanoparticles and different iron sources on growth, and antioxidants in maize plants under salts stress: life cycle study

Exogenous application of iron (Fe) may alleviate salinity stress in plants growing in saline soils. This comparative study evaluated the comparative residual effects of iron nanoparticles (FNp) with two other Fe sources including iron-sulphate (FS) and iron-chelate (FC) on maize (Zea mays L.) crop grown under salt stress. All three Fe sources were applied at the rate of 15 and 25 mg/kg of soil before the sowing of wheat (an earlier crop; following the sequence of crop rotation) and no further Fe amendments were added later for the maize crop. Results revealed that FNp application at 25 mg/kg (FNp-2) substantially increased maize height, root length, root dry weight, shoot dry weight, and grain weightby 80.7%, 111.1%, 45.7%, 59.5%, and 77.2% respectively, as compared to the normal controls; and 62.6%, 81.3%, 65.1%, 78%, and 61.2% as compared to salt-stressed controls, respectively. The FNp-2 treatment gave higher activities of antioxidant enzymes, such as superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase compared to salt stressed control (50.6%, 51%, 48.5%, and 49.2%, respectively). The FNp-2 treatment also produced more photosynthetic pigments and better physiological markers: higher chlorophyll a contents by 49.9%, chlorophyll b contents by 67.2%, carotenoids by 62.5%, total chlorophyll contents by 50.3%, membrane stability index by 59.1%, leaf water relative contents by 60.3% as compared to salt stressed control. The highest Fe and Zn concentrations in maize roots, shoots, and grains were observed in FNp treatment as compared to salts stressed control. Higher application rates of Fe from all the sources also delivered better outcomes in alleviating salinity stress in maize compared to their respective low application rates. The study demonstrated that FNp application alleviated salinity stress, increased nutrient uptake and enhanced the yield of maize grown on saline soils.

Deciphering the regulation of transporters and mitogen-activated protein kinase in arsenic and iron exposed rice

This study investigates the influence of arsenic (As) and iron (Fe) on the molecular aspects of rice plants. The mRNA-abundance of As (OsLsi, OsPHT, OsNRAMP1, OsABCC1) and Fe (OsIRT, OsNRAMP1, OsYSL, OsFRDL1, OsVIT2, OsSAMS1, OsNAS, OsNAAT1, OsDMAS1, OsTOM1, OsFER) related genes has been observed in 12-d old As and Fe impacted rice varieties. Analyses of phytosiderophores synthesis and Fe-uptake genes affirm the existence of specialized Fe-uptake strategies in rice with varieties PB-1 and Varsha favouring strategy I and II, respectively. Expression of OsNAS3, OsVIT2, OsFER and OsABCC1 indicated PB-1's tolerance towards Fe and As. Analysis of mitogen-activated protein kinase cascade members (OsMKK3, OsMKK4, OsMKK6, OsMPK3, OsMPK4, OsMPK7, and OsMPK14) revealed their importance in the fine adjustment of As/Fe in the rice system. A conditional network map was generated based on the gene expression pattern that unfolded the differential dynamics of both rice varieties. The mating based split ubiquitin system determined the interaction of OsIRT1 with OsMPK3, and OsLsi1 with both OsMPK3 and OsMPK4. In-silico tools also confirmed the binding affinities of OsARM1 with OsLsi1, OsMPK3 and OsMPK4, and of OsIDEF1/OsIRO2 with OsIRT1 and OsMPK3, supporting our hypothesis that OsARM1, OsIDEF1, OsIRO2 were active in the connections discovered by mbSUS.

Silicon reduces toxicity and accumulation of arsenic and cadmium in cereal crops: A meta-analysis, mechanism, and perspective study

Arsenic (As) and cadmium (Cd) are two toxic metal(loid)s that pose significant risks to food security and human health. Silicon (Si) has attracted substantial attention because of its positive effects on alleviating the toxicity and accumulation of As and Cd in crops. However, our current knowledge of the comprehensive effects and detailed mechanisms of Si amendment is limited. In this study, a global meta-analysis of 248 original articles with over 7000 paired observations was conducted to evaluate Si-mediated effects on growth and As and Cd accumulation in rice (Oryza sativa L.), wheat (Triticum aestivum L.), and maize (Zea mays L.). Si application increases the biomass of these crops under As and/or Cd contamination. Si amendment also decreased shoot As and Cd accumulation by 24.1 % (20.6 to 27.5 %) and 31.9 % (29.0 to 31.9 %), respectively. Furthermore, the Si amendment reduced the human health risks posed by As (2.6 %) and Cd (12.9 %) in crop grains. Si-induced inhibition of Cd accumulation is associated with decreased Cd bioavailability and the downregulation of gene expression. The regulation of gene expression by Si addition was the driving factor limiting shoot As accumulation. Overall, our analysis demonstrated that Si amendment has great potential to reduce the toxicity and accumulation of As and/or Cd in crops, providing a scientific basis for promoting food safety globally.

Role of methylglyoxal and glyoxalase in the regulation of plant response to heavy metal stress

KEY MESSAGE

Methylglyoxal and glyoxalase function a significant role in plant response to heavy metal stress. We update and discuss the most recent developments of methylglyoxal and glyoxalase in regulating plant response to heavy metal stress. Methylglyoxal (MG), a by-product of several metabolic processes, is created by both enzymatic and non-enzymatic mechanisms. It plays an important role in plant growth and development, signal transduction, and response to heavy metal stress (HMS). Changes in MG content and glyoxalase (GLY) activity under HMS imply that they may be potential biomarkers of plant stress resistance. In this review, we summarize recent advances in research on the mechanisms of MG and GLY in the regulation of plant responses to HMS. It has been discovered that appropriate concentrations of MG assist plants in maintaining a balance between growth and development and survival defense, therefore shielding them from heavy metal harm. MG and GLY regulate plant physiological processes by remodeling cellular redox homeostasis, regulating stomatal movement, and crosstalking with other signaling molecules (including abscisic acid, gibberellic acid, jasmonic acid, cytokinin, salicylic acid, melatonin, ethylene, hydrogen sulfide, and nitric oxide). We also discuss the involvement of MG and GLY in the regulation of plant responses to HMS at the transcriptional, translational, and metabolic levels. Lastly, considering the current state of research, we present a perspective on the future direction of MG research to elucidate the MG anti-stress mechanism and offer a theoretical foundation and useful advice for the remediation of heavy metal-contaminated environments in the future.

Nanoparticles synergy: Enhancing wheat (Triticum aestivum L.) cadmium tolerance with iron oxide and selenium

Nanotechnology is capturing great interest worldwide due to their stirring applications in various fields and also individual application of iron oxide nanoparticle (FeO - NPs) and selenium nanoparticles (Se - NPs) have been studied in many literatures. However, the combined application of FeO and Se - NPs is a novel approach and studied in only few studies. For this purpose, a pot experiment was conducted to examine various growth and biochemical parameters in wheat (Triticum aestivum L.) under the toxic concentration of cadmium (Cd) i.e., 50 mg kg-1 which were primed with combined application of two levels of FeO and Se - NPs i.e., 15 and 30 mg L-1 respectively. The results showed that the Cd toxicity in the soil showed a significantly (P < 0.05) declined in the growth, gas exchange attributes, sugars, AsA-GSH cycle, cellular fractionation, proline metabolism in T. aestivum. However, Cd toxicity significantly (P < 0.05) increased oxidative stress biomarkers, enzymatic and non-enzymatic antioxidants including their gene expression in T. aestivum. Although, the application of FeO and Se - NPs showed a significant (P < 0.05) increase in the plant growth and biomass, gas exchange characteristics, enzymatic and non-enzymatic compounds and their gene expression and also decreased the oxidative stress, and Cd uptake. In addition, individual or combined application of FeO and Se - NPs enhanced the cellular fractionation and decreases the proline metabolism and AsA - GSH cycle in T. aestivum. These results open new insights for sustainable agriculture practices and hold immense promise in addressing the pressing challenges of heavy metal contamination in agricultural soils.

Nano-enabled agrochemicals: mitigating heavy metal toxicity and enhancing crop adaptability for sustainable crop production

The primary factors that restrict agricultural productivity and jeopardize human and food safety are heavy metals (HMs), including arsenic, cadmium, lead, and aluminum, which adversely impact crop yields and quality. Plants, in their adaptability, proactively engage in a multitude of intricate processes to counteract the impacts of HM toxicity. These processes orchestrate profound transformations at biomolecular levels, showing the plant's ability to adapt and thrive in adversity. In the past few decades, HM stress tolerance in crops has been successfully addressed through a combination of traditional breeding techniques, cutting-edge genetic engineering methods, and the strategic implementation of marker-dependent breeding approaches. Given the remarkable progress achieved in this domain, it has become imperative to adopt integrated methods that mitigate potential risks and impacts arising from environmental contamination on yields, which is crucial as we endeavor to forge ahead with the establishment of enduring agricultural systems. In this manner, nanotechnology has emerged as a viable field in agricultural sciences. The potential applications are extensive, encompassing the regulation of environmental stressors like toxic metals, improving the efficiency of nutrient consumption and alleviating climate change effects. Integrating nanotechnology and nanomaterials in agrochemicals has successfully mitigated the drawbacks associated with traditional agrochemicals, including challenges like organic solvent pollution, susceptibility to photolysis, and restricted bioavailability. Numerous studies clearly show the immense potential of nanomaterials and nanofertilizers in tackling the acute crisis of HM toxicity in crop production. This review seeks to delve into using NPs as agrochemicals to effectively mitigate HM toxicity and enhance crop resilience, thereby fostering an environmentally friendly and economically viable approach toward sustainable agricultural advancement in the foreseeable future.

Uptake and bioaccumulation of iron oxide nanoparticles (Fe3O4) in barley (Hordeum vulgare L.): effect of particle-size

Root-to-shoot translocation of nanoparticles (NPs) is a matter of interest due to their possible unprecedented effects on biota. Properties of NPs, such as structure, surface charge or coating, and size, determine their uptake by cells. This study investigates the size effect of iron oxide (Fe3O4) NPs on plant uptake, translocation, and physiology. For this purpose, Fe3O4 NPs having about 10 and 100 nm in average sizes (namely NP10 and NP100) were hydroponically subjected to barley (Hordeum vulgare L.) in different doses (50, 100, and 200 mg/L) at germination (5 days) and seedling (3 weeks) stages. Results revealed that particle size does not significantly influence the seedlings' growth but improves germination. The iron content in root and leaf tissues gradually increased with increasing NP10 and NP100 concentrations, revealing their root-to-shoot translocation. This result was confirmed by vibrating sample magnetometry analysis, where the magnetic signals increased with increasing NP doses. The translocation of NPs enhanced chlorophyll and carotenoid contents, suggesting their contribution to plant pigmentation. On the other hand, catalase activity and H2O2 production were higher in NP10-treated roots compared to NP100-treated ones. Besides, confocal microscopy revealed that NP10 leads to cell membrane damages. These findings showed that Fe3O4 NPs were efficiently taken up by the roots and transported to the leaves regardless of the size factor. However, small-sized Fe3O4 NPs may be more reactive due to their size properties and may cause cell stress and membrane damage. This study may help us better understand the size effect of NPs in nanoparticle-plant interaction.

Unveiling Innovative Approaches to Mitigate Metals/Metalloids Toxicity for Sustainable Agriculture

Due to anthropogenic activities, environmental pollution of heavy metals/metalloids (HMs) has increased and received growing attention in recent decades. Plants growing in HM-contaminated soils have slower growth and development, resulting in lower agricultural yield. Exposure to HMs leads to the generation of free radicals (oxidative stress), which alters plant morpho-physiological and biochemical pathways at the cellular and tissue levels. Plants have evolved complex defense mechanisms to avoid or tolerate the toxic effects of HMs, including HMs absorption and accumulation in cell organelles, immobilization by forming complexes with organic chelates, extraction via numerous transporters, ion channels, signaling cascades, and transcription elements, among others. Nonetheless, these internal defensive mechanisms are insufficient to overcome HMs toxicity. Therefore, unveiling HMs adaptation and tolerance mechanisms is necessary for sustainable agriculture. Recent breakthroughs in cutting-edge approaches such as phytohormone and gasotransmitters application, nanotechnology, omics, and genetic engineering tools have identified molecular regulators linked to HMs tolerance, which may be applied to generate HMs-tolerant future plants. This review summarizes numerous systems that plants have adapted to resist HMs toxicity, such as physiological, biochemical, and molecular responses. Diverse adaptation strategies have also been comprehensively presented to advance plant resilience to HMs toxicity that could enable sustainable agricultural production.

Iron reprogrammes the root system architecture by regulating OsWRKY71 in arsenic-stressed rice (Oryza sativa L.)

Iron (Fe) has been critically reported to act as a signal that can be interpreted to activate the molecular mechanisms involved in root developmental processes. Arsenic (As) is a well-known metalloid that restricts the growth and productivity of rice plants by altering their root architecture. Since root system architecture (RSA) under As stress targets WRKY transcription factors (TFs) and their interaction partners, the current investigation was carried out to better understand the Fe-dependent dynamics of RSA and its participation in this process. Here, we analyzed the effects of As and Fe (alone or in combination) exposed to hydroponically grown rice roots of 12-day-old plants. Our research showed that adding As to Fe changed how OsWRKY71 was expressed and improved the morphology and anatomy of the rice roots in Ratna and Lalat varieties. As + Fe treatment also manifested the biochemical parameters. OsWRKY71, revealed an up-regulation (Fe alone and As + Fe conditions) and down-regulation (As stress) in both varieties, in comparison to the controls. The improved root anatomy and root oxidizability indicated the enhanced capability of Lalat over the Ratna variety to induce OsWRKY71 for the better development of RSA during As + Fe treatment. Further, OsWRKY71 has revealed the presence of gibberellin-responsive cis-regulatory elements (GAREs) in its promoter region, indicating the involvement of OsWRKY71 in the gibberellin pathway. Molecular docking revealed that OsWRKY71 and SLR1 (DELLA protein) interact positively, which supports the hypothesis that Fe alters RSA by regulating OsWRKY71 through the gibberellin pathway in As-stressed rice.

Enhancing growth, vitality, and aromatic richness: unveiling the dual magic of silicon dioxide and titanium dioxide nanoparticles in Ocimum tenuiflorum L

Ocimum tenuiflorum, commonly known as "Holy basil," is renowned for its notable medicinal and aromatic attributes. Its unique fragrance attributes to specific volatile phytochemicals, primarily belonging to terpenoid and/or phenylpropanoid classes, found within their essential oils. The use of nanoparticles (NPs) in agriculture has attracted attention among plant researchers. However, the impact of NPs on the modulation of morpho-physiological aspects and essential oil production in medicinal plants has received limited attention. Consequently, the present study aimed to explore the effect of silicon dioxide (SiO2) and titanium dioxide (TiO2) nanoparticles at various concentrations (viz., DDW (control), Si50+Ti50, Si100+Ti50, Si100+Ti100, Si200+Ti100, Si100+Ti200 and Si200+Ti200 mg L-1) on growth, physiology and essential oil production of O. tenuiflorum at 120 days after planting (DAP). The results demonstrated that the combined application of Si and Ti (Si100+Ti100 mg L-1) exhibited the most favourable outcomes compared to the other combinational treatments. This optimal treatment significantly increased the vegetative growth parameters (root length (33.5%), shoot length (39.2%), fresh weight (62.7%) and dry weight (28.5%)), photosynthetic parameters, enzymatic activities (nitrate reductase and carbonic anhydrase), the overall area of PGTs (peltate glandular trichomes) and essential oil content (172.4%) and yield (323.1%), compared to the control plants. Furthermore, the GCMS analysis showed optimal treatment (Si100+Ti100) significantly improved the content (43.3%) and yield (151.3%) of eugenol, the primary active component of the essential oil. This study uncovers a remarkable and optimal combination of SiO2 and TiO2 nanoparticles that effectively enhances the growth, physiology, and essential oil production in Holy basil. These findings offer valuable insights into maximizing the potential benefits of its use in industrial applications.

Mixed effects and co-transfer of CeO2 NPs and arsenic in the pakchoi-snail food chain

Nanomaterial application in agriculture offers novel solutions for soil arsenic (As) pollution control, yet safety along the food chain is of concern. We comprehensively assessed CeO2 nanoparticles (NPs) foliar application effects on As uptake by pakchoi and their presence in the pakchoi-snail food chain. CeO2 NPs reduced As transfer from pakchoi roots to shoots by 37.9%, lowered As in snail foot by 39%, and halved human As exposure risk. The NPs alleviated pakchoi shoot As toxicity by regulating antioxidants, enhancing water use efficiency, and photosynthesis. CeO2 +As treatment raised GSH/GSSG ratios by 38.92%- 167.54%, leading to an increased AsIII/AsV ratio and inorganic As detoxification compared to As alone. Metabolomics revealed CeO2's rapid As response via phosphatidylinositol signaling. The enzyme-like activity of CeO2 NPs may drive these effects. While CeO2 foliar application accumulated Ce on pakchoi leaves, > 99% of Ce was excreted following snail consumption. Ce transfer from pakchoi leaves to snail foot was minimal (trophic transfer factor ∼0.00007) due to limited bioavailability. The target hazard quotient of Ce in pakchoi shoot (1.21 ± 0.18) and snails (0.0016 ± 0.0004) indicated low exposure risk, suggesting a 'risk filter' effect for CeO2. Our results contribute to the safe and sustainable application of CeO2 NPs in the future implication.

Nanoparticles modulate heavy-metal and arsenic stress in food crops: Hormesis for food security/safety and public health

Heavy metal and arsenic (HM-As) contamination at the soil-food crop interface is a threat to food security/safety and public health worldwide. The potential ecotoxicological effects of HM-As on food crops can perturb normal physiological, biochemical, and molecular processes. To protect food safety and human health, nanoparticles (NPs) can be applied to seed priming and soil amendment, as 'manifestation of hormesis' to modulate HM-As-induced oxidative stress in edible crops. This review provides a comprehensive overview of NPs-mediated alleviation of HM-As stress in food crops and resulting hormetic effects. The underlying biochemical and molecular mechanisms in the amelioration of HM-As-induced oxidative stress is delineated by covering the various aspects of the interaction of NPs (e.g., magnetic particles, silicon, metal oxides, selenium, and carbon nanotubes) with plant microbes, phytohormone, signaling molecules, and plant-growth bioregulators (e.g., salicylic acid and melatonin). With biotechnical advances (such as clustered regularly interspaced short palindromic repeats (CRISPR) gene editing and omics), the efficacy of NPs and associated hormesis has been augmented to produce "pollution-safe designer cultivars" in HM-As-stressed agriculture systems. Future research into nanoscale technological innovations should thus be directed toward achieving food security, sustainable development goals, and human well-being, with the aid of HM-As stress resilient food crops.

Magnesium oxide nanoparticles alleviate arsenic toxicity, reduce oxidative stress and arsenic accumulation in rice (Oryza sativa L.)

Magnesium oxide nanoparticles (MgO NPs) have been attracted by the scientific community for their combating action against heavy metal stress in plants. However, their role towards the mitigation of arsenic (As) induced toxicity is still obscure. In the present study, MgO NPs were synthesized through the green route and assessed their efficacy towards the reduction of As accumulation and phytotoxicity in As-stressed rice cultivar MTU-1010 under laboratory conditions. Initially, rice seedlings were grown under separate and combined applications of As (10 mg/L) and MgO NPs (0, 10, 50, and 100 mg/L) and further analyzed plant growth attributes and As accumulation in rice seedlings. Characterization of biosynthesized MgO NPs by UV-Vis spectrophotometer, transmission electron microscopy (TEM), scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis showed the cubic in shape, and crystalline nature (73.10%) with average size ranges from 17-23 nm. The growth experiment showed a significant (p < 0.05) increase in seed germination, seedling growth, photosynthetic and other pigments content, and biomass accumulation in rice seedlings under the combined application of As (10 mg/L) and MgO NPs (50 mg/L) as compared to only As (10 mg/L) treatment. Additionally, As exposure resulted in declined primary metabolites such as soluble sugars and protein. However, the application of MgO NPs exhibited the alleviation of As toxicity through significant (p < 0.05) reduction of As accumulation by 34 and 53% in roots and 44 and 62% in shoots of rice seedlings under 50 and 100 mg/L MgO NPs supplementations, respectively and restored the accumulation of the primary metabolites. Furthermore, MgO NPs demonstrated the ability to scavenge reactive oxygen species (ROS) like hydrogen peroxide (H2O2) and superoxide anion (O2•-), through significant (p < 0.05) promotion of non-enzymatic (carotenoid, anthocyanin, flavonoid, and proline) and enzymatic (CAT, POD, and SOD) antioxidant defence under As stress. These findings highlighted the potential of green synthesized MgO NPs towards the mitigation of As contamination in rice plants. However, future study is necessary to unfold the actual mechanisms responsible for the protective effects of MgO NPs and to screen out the optimal dose to be used to formulate a potent nanofertilizer for sustainable rice production in metal-contaminated soils.

Root Exposure of Graphitic Carbon Nitride (g-C3N4) Modulates Metabolite Profile and Endophytic Bacterial Community to Alleviate Cadmium- and Arsenate-Induced Phytotoxicity to Rice (Oryza sativa L.)

To investigate the mechanisms by which g-C3N4 alleviates metal(loid)-induced phytotoxicity, rice seedlings were exposed to 100 and 250 mg/kg graphitic carbon nitride (g-C3N4) with or without coexposure to 10 mg/kg Cd and 50 mg/kg As for 30 days. Treatment with 250 mg/kg g-C3N4 significantly increased shoot and root fresh weight by 22.4-29.9%, reduced Cd and As accumulations in rice tissues by 20.6-26.6%, and elevated the content of essential nutrients (e.g., K, S, Mg, Cu, and Zn) compared to untreated controls. High-throughput sequencing showed that g-C3N4 treatment increased the proportion of plant-growth-promoting endophytic bacteria, including Streptomyces, Saccharimonadales, and Thermosporothrix, by 0.5-3.30-fold; these groups are known to be important to plant nutrient assimilation, as well as metal(loid) resistance and bioremediation. In addition, the population of Deinococcus was decreased by 72.3%; this genus is known to induce biotransformation As(V) to As(III). Metabolomics analyses highlighted differentially expressed metabolites (DEMs) involved in the metabolism of tyrosine metabolism, pyrimidines, and purines, as well as phenylpropanoid biosynthesis related to Cd/As-induced phytotoxicity. In the phenylpropanoid biosynthesis pathway, the increased expression of 4-coumarate (1.13-fold) and sinapyl alcohol (1.26-fold) triggered by g-C3N4 coexposure with Cd or As played a critical role in promoting plant growth and enhancing rice resistance against metal(loid) stresses. Our findings demonstrate the potential of g-C3N4 to enhance plant growth and minimize the Cd/As-induced toxicity in rice and provide a promising nanoenabled strategy for remediating heavy metal(loid)-contaminated soil.

Zinc oxide nanoparticles mitigated the arsenic induced oxidative stress through modulation of physio-biochemical aspects and nutritional ions homeostasis in rice (Oryza sativa L.)

Zinc oxide nanoparticles (nZn) have emerged as vital agents in combating arsenic (As) stress in plants. However, their role in mitigation of As induced oxidative stress is less studied. Therefore, this study aimed to assess the comparative role of nZn and ZnO in alleviating As toxicity in rice genotype "9311". The results of this study revealed that nZn demonstrated superior efficacy compared to ZnO in mitigating As toxicity. This superiority can be attributed to the unique size and structure of nZn, which enhances its ability to alleviate As toxicity. Exposure to As at a concentration of 25 μM L-1 led to significant reductions in shoot length, root length, shoot dry weight, and root dry weight by 39%, 51%, 30%, and 46%, respectively, while the accumulation of essential nutrients such as magnesium (Mg), potassium (K), iron (Fe), manganese (Mn), and zinc (Zn) decreased by 25%-47% compared to the control plants. Additionally, As exposure resulted in stomatal closure and structural damage to vital cellular components such as grana thylakoids (GT), starch granules (SG), and the nucleolus. However, the application of nZn at a concentration of 30 mg L-1 exhibited significant alleviation of As toxicity, resulting in a reduction of As accumulation by 54% in shoots and 62% in roots of rice seedlings. Furthermore, nZn demonstrated the ability to scavenge reactive oxygen species (ROS) like hydrogen peroxide (H2O2) and superoxide anion (O2.-), while significantly promoted the gas exchange parameters, chlorophyll content (SPAD value), fluorescence efficiency (Fv/m) and antioxidant enzyme activities under As-induced stress. These findings highlight the potential of nZn in mitigating the adverse impacts of As contamination in rice plants. However, further research is necessary to fully comprehend the underlying mechanisms responsible for the protective effects of nZn and to determine the optimal conditions for their application in real-world agricultural settings.

Comparative efficacy of silicon and iron oxide nanoparticles towards improving the plant growth and mitigating arsenic toxicity in wheat (Triticum aestivum L.)

Nano-enabled agriculture has emerged as an attractive approach for facilitating soil pollution mitigation and enhancing crop production and nutrition. In this study, we conducted a greenhouse experiment to explore the efficacy of silicon oxide nanoparticles (SiONPs) and iron oxide nanoparticles (FeONPs) in alleviating arsenic (As) toxicity in wheat (Triticum aestivum L.) and elucidated the underlying mechanisms involved. The application of SiONPs and FeONPs at 25, 50, and 100 mg kg-1 soil concentration significantly reduced As toxicity and concurrently improved plant growth performance, including plant height, dry matter, spike length, and grain yield. The biochemical analysis showed that the enhanced plant growth was mainly due to stimulated antioxidative enzymes (catalase, superoxide dismutase, peroxidase) and reduced reactive oxygen species (electrolyte leakage, malondialdehyde, and hydrogen peroxide) in wheat seedlings under As stress upon NPs application. The nanoparticles (NPs) exposure also enhanced the photosynthesis efficiency, including the total chlorophyll and carotenoid contents as compared with the control treatment. Importantly, soil amendments with 100 mg kg-1 FeONPs significantly reduced the acropetal As translocation in the plant root, shoot and grains by 74%, 54% and 78%, respectively, as compared with the control treatment under As stress condition, with relatively lower reduction levels (i.e., 64%, 37% and 58% for the plant root, shoot and grains, respectively) for SiONPs amendment. Overall, the application of NPs especially the FeONPs as nanoferlizers for agricultural crops is a promising approach towards mitigating the negative impact of HMs toxicity, ensuring food safety, and promoting future sustainable agriculture.

Regulatory Mechanisms Underlying Arsenic Uptake, Transport, and Detoxification in Rice

Arsenic (As) is a metalloid environmental pollutant ubiquitous in nature that causes chronic and irreversible poisoning to humans through its bioaccumulation in the trophic chain. Rice, the staple food crop for 350 million people worldwide, accumulates As more easily compared to other cereal crops due to its growth characteristics. Therefore, an in-depth understanding of the molecular regulatory mechanisms underlying As uptake, transport, and detoxification in rice is of great significance to solving the issue of As bioaccumulation in rice, improving its quality and safety and protecting human health. This review summarizes recent studies on the molecular mechanisms of As toxicity, uptake, transport, redistribution, regulation, and detoxification in rice. It aims to provide novel insights and approaches for preventing and controlling As bioaccumulation in rice plants, especially reducing As accumulation in rice grains.

The beneficial effects of bare and CMC-supported α-FeOOH, Fe3O4, and α-Fe2O3 nanoparticles on growth, nutrient content, and essential oil of summer savory (Satureja hortensis L.) under Cd, Pb and Zn stresses

This research studies the impacts of iron oxide nanoparticles (FeONPs) on alleviating the toxic effects of cadmium (Cd), lead (Pb), and zinc (Zn) on summer savory (Satureja hortensis L.). Different types of soil additives, including bare and carboxymethylcellulose (CMC)-supported hematite (α-Fe₂O₃), goethite (α-FeOOH), and magnetite (Fe₃O₄), were applied at three rates (0, 0.25, and 0.5% w/w) to a Cd, Pb, and Zn-contaminated soil sample. The experimental results showed that the application of FeONPs increased plant height, dry weights of shoot and root, and yield and content of essential oil. Bare and CMC-supported FeONPs increased the content of K, P, and Fe in the aerial parts of summer savory. However, these soil additives reduced the contents of Cd, Pb, and Zn in plant tissues. CMC-supported FeONPs proved to be more efficient additives in diminishing the toxic effects of Cd, Pb, and Zn in summer savory compared to their bare forms. Bare and CMC-supported goethite NPs were able to restrict the uptake of Cd, Pb, and Zn by summer savory roots in the metal-contaminated soil. The application of CMC-supported goethite at an application dose of 0.5% (w/w) increased shoot dry weight, shoot concentrations of K, P, and Fe, and yield of essential oil by about 62.6, 76.6, 77.1, 210, and 230%, respectively. Conversely, they reduced shoot concentrations of Cd, Pb, and Zn by about 64.6, 68.7, and 40.6%, respectively, compared to the control. These are significant results and indicate that CMC-supported goethite is likely to be the most effective soil additive in diminishing the toxicity of Cd, Pb, and Zn to metal-stressed summer savory.

Alleviation of arsenic toxicity in pepper plants by aminolevulinic acid and heme through modulating its sequestration and distribution within cell organelles

Aminolevulinic acid (ALA) is essential for chlorophyll and heme synthesis. However, whether heme interacts with ALA to elicit antioxidants in arsenic (As)-exposed plants is still unknown. ALA was applied daily to pepper plants for 3 days prior to beginning As stress (As-S). Then, As-S was initiated for 14 days by employing sodium hydrogen arsenate heptahydrate (0.1 mM AsV). Arsenic treatment decreased photosynthetic pigments (chl a by 38% and chl b by 28%), biomass by 24%, and heme by 47% content, but it elevated contents of malondialdehyde (MDA) by 3.3-fold, hydrogen peroxide (H₂O₂) by 2.3-fold, glutathione (GSH), methylglyoxal (MG), and phytochelatins (PCs) and electrolyte leakage (EL) by 2.3-fold along with enhanced subcellular As concentration in the pepper plant's roots and leaves. The supplementation of ALA to the As-S-pepper seedlings enhanced the amount of chlorophyll, heme content, and antioxidant enzyme activity as well as plant growth, while it reduced the levels of H₂O₂, MDA, and EL. ALA boosted GSH and phytochelates (PCs) in the As-S-seedlings by controlling As sequestration and rendering it harmless. The addition of ALA enhanced the amount of As that accumulated in the root vacuoles and reduced the poisonousness of the soluble As in the vacuoles. The ALA treatment facilitated the deposition and fixation of As in the vacuoles and cell walls, thereby reducing the transport of As to other cell organelles. This mechanism may have contributed to the observed decrease in As accumulation in the leaves. The administration of 0.5 mM hemin (H) (a source of heme) significantly enhanced ALA-induced arsenic stress tolerance. Hemopexin (Hx, 0.4 μg L^-1), a heme scavenger, was treated with the As-S plants along with ALA and ALA + H to observe if heme was a factor in ALA's increased As-S tolerance. Heme synthesis/accumulation in the pepper plants was reduced by Hx, which counteracted the positive effects of ALA. Supplementation of H along with ALA + Hx reversed the negative effects of Hx, demonstrating that heme is required for ALA-induced seedling As-S tolerance.

Supplementation with Ascophyllum nodosum extracts mitigates arsenic toxicity by modulating reactive oxygen species metabolism and reducing oxidative stress in rice

Ascophyllum nodosum extract (ANE) is considered as an effective source of biostimulants that have the potential of ameliorating the negative impact of different abiotic stresses in plants. Considering the growth-promoting ability and other regulatory roles of ANE, the present investigation was executed to evaluate the role of ANE in conferring arsenic (As) tolerance in rice (Oryza sativa L. cv. BRRI dhan89). Rice seedlings (35-d-old) were exposed to two doses of sodium arsenate (As1 - 50 mg As kg-1 soil; As2 - 100 mg As kg-1 soil) at 25 days after transplanting through irrigation, whereas only water was applied to the control. Foliar application of 0.1% ANE was also supplemented under control as well as As-stressed conditions at 7 days intervals for 5 times. Arsenic-induced oxidative stress was evident through a sharp increase in lipid peroxidation, hydrogen peroxide, methylglyoxal, and electrolyte leakage in the As-treated plants. As a consequence, plant growth and biomass, leaf relative water content, as well as yield attributes were reduced noticeably. On the other hand, ANE supplemented plants accumulated enhanced levels of ascorbate and glutathione, their redox balance, and the activities of antioxidant and glyoxalase enzymes viz. ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, glutathione reductase, catalase, glutathione peroxidase, and activities of glyoxalase I and glyoxalase II, respectively. Furthermore, relative water content, plant growth, yield attributes and yield were increased in the As-treated rice plants with ANE supplementation. The results reflected that foliar spray with ANE alleviated As-induced oxidative stress in rice plants by modulating the antioxidative defense and glyoxalase system.

Arsenic and iron bioavailability in Caco-2 cells: The influence of their co-existence and concentration

Arsenic (As) exposure in humans is primarily caused through food and drinking water. Iron (Fe) is one of the most common element of the human and can influence the toxicity and bioavailability of As. However, information on the interaction between As and Fe when present together is limited. In this study, the interaction effects of Fe(III) (0, 3, and 10 mg/L) and As (As(III) at 0, 0.05, 0.1 mg/L, and As(V) at 0, 0.1, and 2 mg/L, respectively) on their absorption and bioavailability in Caco-2 cells were analyzed. As(III) absorption significantly decreased with the addition of Fe, while Fe absorption significantly increased. Compared with 0.1 mg/L As(III) addition alone, 3 and 10 mg/L Fe(III) addition significantly reduced the As(III) absorption by 8.6 and 11 μg/L, respectively. The absorption of As and Fe(III) and the bioavailability of Fe(III) significantly increased with the addition of As(III/V). Compared with 10 mg/L Fe(III) alone, the absorption of As(III) was significantly increased by 1 and 1.3 mg/L with 0.05 and 0.1 mg/L As(III) addition, respectively. Furthermore, the absorption and bioavailability of Fe(III) were significantly increased by 1.2 mg/L and 8% and 1.2 mg/L and 8.2%, respectively, after adding 0.1 and 2 mg/L As(V).

Heavy metal stabilization remediation in polluted soils with stabilizing materials: a review

The remediation of soil contaminated by heavy metals has long been a concern of academics. This is due to the fact that heavy metals discharged into the environment as a result of natural and anthropogenic activities may have detrimental consequences for human health, the ecological environment, the economy, and society. Metal stabilization has received considerable attention and has shown to be a promising soil remediation option among the several techniques for the remediation of heavy metal-contaminated soils. This review discusses various stabilizing materials, including inorganic materials like clay minerals, phosphorus-containing materials, calcium silicon materials, metals, and metal oxides, as well as organic materials like manure, municipal solid waste, and biochar, for the remediation of heavy metal-contaminated soils. Through diverse remediation processes such as adsorption, complexation, precipitation, and redox reactions, these additives efficiently limit the biological effectiveness of heavy metals in soils. It should also be emphasized that the effectiveness of metal stabilization is influenced by soil pH, organic matter content, amendment type and dosage, heavy metal species and contamination level, and plant variety. Furthermore, a comprehensive overview of the methods for evaluating the effectiveness of heavy metal stabilization based on soil physicochemical properties, heavy metal morphology, and bioactivity has also been provided. At the same time, it is critical to assess the stability and timeliness of the heavy metals' long-term remedial effect. Finally, the priority should be on developing novel, efficient, environmentally friendly, and economically feasible stabilizing agents, as well as establishing a systematic assessment method and criteria for analyzing their long-term effects.

Nanobionics: A Sustainable Agricultural Approach towards Understanding Plant Response to Heavy Metals, Drought, and Salt Stress

In the current scenario, the rising concentration of heavy metals (HMs) due to anthropogenic activities is a severe problem. Plants are very much affected by HM pollution as well as other abiotic stress such as salinity and drought. It is very important to fulfil the nutritional demands of an ever-growing population in these adverse environmental conditions and/or stresses. Remediation of HM in contaminated soil is executed through physical and chemical processes which are costly, time-consuming, and non-sustainable. The application of nanobionics in crop resilience with enhanced stress tolerance may be the safe and sustainable strategy to increase crop yield. Thus, this review emphasizes the impact of nanobionics on the physiological traits and growth indices of plants. Major concerns and stress tolerance associated with the use of nanobionics are also deliberated concisely. The nanobionic approach to plant physiological traits and stress tolerance would lead to an epoch of plant research at the frontier of nanotechnology and plant biology.

Potential Effects of Metal Oxides on Agricultural Production of Rice: A Mini Review

The extensive usage of metal oxide nanoparticles has aided in the spread and accumulation of these nanoparticles in the environment, potentially endangering both human health and the agroecological system. This research describes in detail the hazardous and advantageous impacts of common metal oxide nanomaterials, such as iron oxide, copper oxide, and zinc oxide, on the life cycle of rice. In-depth analyses are conducted on the transport patterns of nanoparticles in rice, the plant's reaction to stress, the reduction of heavy metal stress, and the improvement of rice quality by metal oxide nanoparticles, all of which are of significant interest in this subject. It is emphasized that from the perspective of advancing the field of nanoagriculture, the next stage of research should focus more on the molecular mechanisms of the effects of metal oxide nanoparticles on rice and the effects of combined use with other biological media. The limitations of the lack of existing studies on the effects of metal oxide nanomaterials on the entire life cycle of rice have been clearly pointed out.

The Role of Nanoparticles in Response of Plants to Abiotic Stress at Physiological, Biochemical, and Molecular Levels

In recent years, the global agricultural system has been unfavorably impacted by adverse environmental changes. These changes in the climate, in turn, have altered the abiotic conditions of plants, affecting plant growth, physiology and production. Abiotic stress in plants is one of the main obstacles to global agricultural production and food security. Therefore, there is a need for the development of novel approaches to overcome these problems and achieve sustainability. Nanotechnology has emerged as one such novel approach to improve crop production, through the utilization of nanoscale products, such as nanofertilizer, nanofungicides, nanoherbicides and nanopesticides. Their ability to cross cellular barriers makes nanoparticles suitable for their application in agriculture. Since they are easily soluble, smaller, and effective for uptake by plants, nanoparticles are widely used as a modern agricultural tool. The implementation of nanoparticles has been found to be effective in improving the qualitative and quantitative aspects of crop production under various biotic and abiotic stress conditions. This review discusses various abiotic stresses to which plants are susceptible and highlights the importance of the application of nanoparticles in combating abiotic stress, in addition to the major physiological, biochemical and molecular-induced changes that can help plants tolerate stress conditions. It also addresses the potential environmental and health impacts as a result of the extensive use of nanoparticles.

Nano-enabled agriculture: How do nanoparticles cross barriers in plants?

Nano-enabled agriculture is a topic of intense research interest. However, our knowledge of how nanoparticles enter plants, plant cells, and organelles is still insufficient. Here, we discuss the barriers that limit the efficient delivery of nanoparticles at the whole-plant and single-cell levels. Some commonly overlooked factors, such as light conditions and surface tension of applied nano-formulations, are discussed. Knowledge gaps regarding plant cell uptake of nanoparticles, such as the effect of electrochemical gradients across organelle membranes on nanoparticle delivery, are analyzed and discussed. The importance of controlling factors such as size, charge, stability, and dispersibility when properly designing nanomaterials for plants is outlined. We mainly focus on understanding how nanoparticles travel across barriers in plants and plant cells and the major factors that limit the efficient delivery of nanoparticles, promoting a better understanding of nanoparticle-plant interactions. We also provide suggestions on the design of nanomaterials for nano-enabled agriculture.

Nanoparticles: The Plant Saviour under Abiotic Stresses

Climate change significantly affects plant growth and productivity by causing different biotic and abiotic stresses to plants. Among the different abiotic stresses, at the top of the list are salinity, drought, temperature extremes, heavy metals and nutrient imbalances, which contribute to large yield losses of crops in various parts of the world, thereby leading to food insecurity issues. In the quest to improve plants' abiotic stress tolerance, many promising techniques are being investigated. These include the use of nanoparticles, which have been shown to have a positive effect on plant performance under stress conditions. Nanoparticles can be used to deliver nutrients to plants, overcome plant diseases and pathogens, and sense and monitor trace elements that are present in soil by absorbing their signals. A better understanding of the mechanisms of nanoparticles that assist plants to cope with abiotic stresses will help towards the development of more long-term strategies against these stresses. However, the intensity of the challenge also warrants more immediate approaches to mitigate these stresses and enhance crop production in the short term. Therefore, this review provides an update of the responses (physiological, biochemical and molecular) of plants affected by nanoparticles under abiotic stress, and potentially effective strategies to enhance production. Taking into consideration all aspects, this review is intended to help researchers from different fields, such as plant science and nanoscience, to better understand possible innovative approaches to deal with abiotic stresses in agriculture.

A review of the influence of nanoparticles on the physiological and biochemical attributes of plants with a focus on the absorption and translocation of toxic trace elements

Trace elements (TEs) from various natural and anthropogenic activities contaminate the agricultural water and soil environments. The use of nanoparticles (NPs) as nano-fertilizers or nano-pesticides is gaining popularity worldwide. The NPs-mediated fertilizers encourage the balanced availability of essential nutrients to plants compared to traditional fertilizers, especially in the presence of excessive amounts of TEs. Moreover, NPs could reduce and/or restrict the bioavailability of TEs to plants due to their high sorption ability. In this review, we summarize the potential influence of NPs on plant physiological attributes, mineral absorption, and TEs sorption, accumulation, and translocation. It also unveils the NPs-mediated TE scavenging-mechanisms at plant and soil interface. NPs immobilized TEs in soil solution effectively by altering the speciation of TEs and modifying the physiological, biochemical, and biological properties of soil. In plants, NPs inhibit the transfer of TEs from roots to shoots by inducing structural modifications, altering gene transcription, and strengthening antioxidant defense mechanisms. On the other hand, the mechanisms underpinning NPs-mediated TEs absorption and cytotoxicity mitigation differ depending on the NPs type, distribution strategy, duration of NP exposure, and plants (e.g., types, varieties, and growth rate). The review highlights that NPs may bring new possibilities for resolving the issue of TE cytotoxicity in crops, which may also assist in reducing the threats to the human dietary system. Although the potential ability of NPs in decontaminating soils is just beginning to be understood, further research is needed to uncover the sub-cellular-based mechanisms of NPs-induced TE scavenging in soils and absorption in plants.

An insight into the act of iron to impede arsenic toxicity in paddy agro-system

Surplus research on the widespread arsenic (As) revealed its disturbing role in obstructing the metabolic function of plants. Also, the predilection of As towards rice has been an interesting topic. Contrary to As, iron (Fe) is an essential micronutrient for all life forms. Past findings propound about the enhanced As-resistance in rice plants during Fe supplementation. Thus, considering the severity of As contamination and resulting exposure through rice crops, as well as the studied cross-talks between As and Fe, we found this topic of relevance. Keeping these in view, we bring this review discussing the presence of As-Fe in the paddy environment, the criticality of Fe plaque in As sequestration, and the effectiveness of various Fe forms to overcome As toxicity in rice. This type of interactive analysis for As and Fe is also crucial in the context of the involvement of Fe in cellular redox activities such as oxidative stress. Also, this piece of work highlights Fe biofortification approaches for better rice varieties with optimum intrinsic Fe and limited As. Though elaborated by others, we lastly present the acquisition and transport mechanisms of both As and Fe in rice tissues. Altogether we suggest that Fe supply and Fe plaque might be a prospective agronomical tool against As poisoning and for phytostabilization, respectively.

Methyl jasmonate increases aluminum tolerance in rice by augmenting the antioxidant defense system, maintaining ion homeostasis, and increasing nonprotein thiol compounds

Aluminum (Al) stress is known as a serious threat to the growth and production of crops in acidic soils. Here, the effects of different concentrations of methyl jasmonate (MJ, 0.5 and 1 µM) on rice plants were investigated hydroponically under different concentrations of Al (0.5 and 1 mM). Aluminum treatments injured membrane lipids and photosynthetic apparatus by reducing the leaf contents of mineral nutrients and increasing the accumulation of free radicals (hydrogen peroxide, methylglyoxal, and superoxide anion), resulting in reduced growth and biomass of rice. In comparison to control plants, 0.5 and 1 μM Al treatments lowered height by 21 and 37% and total dry weight by 24 and 41%, respectively. Exogenously added methyl diminished the inhibitory effects of Al stress on growth and photosynthetic apparatus by restoring ion homeostasis and improving chlorophyll metabolism. The application of MJ, by inducing the activity of antioxidant enzymes and the glyoxalase cycle, lessened the levels of the toxic compounds hydrogen peroxide, methylglyoxal, and superoxide anion and, as a result, dwindled the toxic Al-induced oxidative stress. Methyl jasmonate enhanced the leaf accumulation of nonprotein thiol compounds and improved plant tolerance under Al stress by increasing the activity of enzymes involved in the synthesis of thiol compounds. Methyl jasmonate increased the leaf accumulation of glutathione and phytochelatins in Al-stressed plants by increasing the expression of GSH1, PCS, and ABCC1, which reduced the toxicity of toxic Al accumulated in leaves by sequestering toxic Al in vacuoles. Together, the results revealed that MJ increased the tolerance of rice under Al toxicity by maintaining ion homeostasis, improving the activity of antioxidant enzymes and the glyoxalase system, and increasing the level of non-protein thiol compounds. This research adds to our understanding of how MJ may be used in the future to improve Al stress tolerance in sustainable agriculture.