Silicon nanoparticles more effectively alleviated UV-B stress than silicon in wheat (Triticum aestivum) seedlings

Ascorbic and silicic acid application mitigated toxic effects of ozone in mung bean (Vigna radiata L. Wilczek) by modulating growth, secondary metabolites, water relations, and grain quality attributes

BACKGROUND

Elevated levels of tropospheric ozone (O3) pose a significant threat to plant health and productivity. Developing ozone-tolerant varieties is crucial for mitigating these environmental stresses. This study investigates the effects of ascorbic acid (AA) and silicic acid (SA) treatments on 12 different mung bean varieties under elevated O3 conditions.

RESULTS

A controlled pot experiment was conducted with four treatments: ambient O3 (40-45 ppb), elevated O3 (120 ppb), elevated O3 with silicic acid (0.1 mmol L-1), and high O3 with ascorbic acid (10 mmol L-1). High O3 stress negatively impacted growth attributes across all mung bean cultivars. However, both AA and SA treatments significantly alleviated O3-induced growth reductions. Under O3 stress, osmotic potential, water potential, relative water content, turgor potential, sugars, pod number, amino acids, 100-seed weight, and grain carbohydrates all decreased. In contrast, antioxidant enzymes (ascorbate peroxidase, peroxidase, catalase, and superoxide dismutase), flavonoids, tannins, and grain protein content increased.

CONCLUSION

The NIAB Mung 20-21, NIAB Mung 2006, and NIAB Mung varieties exhibited O3 resistance. Silicic acid proved to be more effective than ascorbic acid in mitigating O3 damage, though a combination of both treatments was the most beneficial for enhancing plant resilience under elevated O3 conditions. © 2025 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Nanosensors for hazardous pesticides and nanofertilizers for sustainable agriculture: contribution of carbon quantum dots

The increasing global population threatens food security, necessitating sustainable agricultural practices. Intensive farming has led to the excessive use of pesticides and fertilizers, contaminating soil and water sources and causing the impairment of the environment. Pesticide residues enter the food chain, posing serious health risks like neurotoxicity, genetic mutations, and diseases such as Alzheimer's, Parkinson's, diabetes, etc. Conventional detection methods are costly, complex, time-consuming, unsuitable for onsite detection, and mostly not eco-friendly. Fluorescence-based nano-biosensors, particularly carbon quantum dots (CQDs), offer a promising alternative to detect pesticides and herbicides due to their high sensitivity, biocompatibility, low toxicity, and photostability. In addition to their sensory application, CQDs could be used as an alternative to conventional chemical fertilizers for crop production. CQD-based nanofertilizers improve nutrient absorption, boost plant growth, and increase resistance to environmental stressors. This review will highlight the key advancements in CQDs in terms of various synthetic techniques and their use as nanosensors and nanofertilizers.

Useful or merely convenient: can enzymatic antioxidant activity be used as a proxy for abiotic stress tolerance?

During their lifespan, plants are often exposed to a broad range of stresses that change their redox balance and lead to accumulation of reactive oxygen species (ROS). The traditional view is that this comes with negative consequences to cells structural integrity and metabolism and, to prevent this, plants evolved a complex and well-coordinated antioxidant defence system that relies on the operation of a range of enzymatic and non-enzymatic antioxidants (AO). Due to the simplicity of measuring their activity, and in light of the persistent dogma that stress-induced ROS accumulation is detrimental for plants, it is not surprising that enzymatic AOs have often been advocated as suitable proxies for stress tolerance as well as potential targets for improving tolerance traits. However, there are a growing number of reports showing either no changes or even down-regulation of AO systems in stressed plants. Moreover, ROS are recognized now as important second messengers operating in both local and systemic signalling, synergistically interacting with the primary stressor, to regulate gene expression needed for optimal acclimatization. This work critically assesses the suitability of using enzymatic AOs as a proxy for stress tolerance or as a target for crop genetic improvement. It is concluded that constitutively higher AO activity may interfere with stress-induced ROS signalling and be a disadvantage for plant stress tolerance.

Bio-efficacy of Nanosilicon in Regulating Oxidative Activity to Control Rice Seedlings Rot Disease Caused by Burkholderia glumae

Bacterial panicle blight and seedling rot diseases in rice plants (Oryza sativa L.) are caused by the pathogenic bacterial Burkholderia glumae. The nanosilicon treatment is gaining attraction but its effectiveness towards B. glumae infection in rice seedlings through regulating enzymatic activities remains largely unexplored. This study aimed to evaluate the bio-efficacy of nanosilicon in controlling seedling rot disease through regulation of peroxidase and polyphenol oxidase enzymes after challenge infected with B. glumae in rice variety MR297 and PadiU Putra. Nanosilicon was applied as seed priming in germination testing at 0, 300, 600, and 900 ppm on both rice varieties before B. glumae inoculation. Both rice seed varieties primed with nanosilicon at 600 ppm exhibited a significant increase in seedling germination performances over control. The rice seedling of MR297 was more responsive to nanosilicon at 600 ppm with only 17.78% of disease severity index over 26.67% in PadiU Putra and was therefore selected for the enzymatic activity screening. The results showed that the foliar spray of nanosilicon rice plants (MR297) significantly increased both peroxidase (POX) at 24 h and polyphenol oxidase (PPO) at 48 h after B. glumae inoculation with 20.44/min/g and 7.46/g activities, respectively. In addition, the plant growth performances were significantly increased compared with control under the same treatment. This demonstrates nanosilicon's potential to control rice seedling rot disease by regulating POX and PPO activities and hence promote plant growth. The application of nanosilicon is an environmentally friendly approach for controlling B. glumae infection at the early rice growing stage.

Silicon dioxide nanoparticles as a protective agent against As(III) toxicity in Vigna mungo L. Hepper

The toxicity of As(III) significantly disrupts the growth and development of plants. In this study, black gram plants were exposed to 75 μM NaAsO2 and 10 mg/L SiO2 NPs, and various physiological, biochemical, and molecular changes were observed. Arsenic toxicity led to a notable reduction in plant development, accompanied by an accumulation of ROS and disturbances in proline levels due to electrolyte production. Treating As(III) contaminated black gram with SiO2 NPs resulted in increased root length and chlorophyll content, while decreasing ROS levels. The application of SiO2 NPs effectively mitigated As(III) toxicity by enhancing the activity of antioxidant enzymes such as peroxidase, catalase, glutathione, and superoxide dismutase, consequently reducing lipid peroxidation attributed to lower ROS production. RNA-seq analysis revealed several differentially expressed genes. Additionally, Fourier Transform Infrared (FTIR) Spectroscopy was utilized to explore the plant's capability to remove arsenic, identifying ligands such as O-H, C-O, C-C, and C-H that aid in the accumulation of heavy metals in plant tissues. An investigation using HR-LC/MS unveiled about 199 potential phytochemical components. A SwissADME analysis of these compounds showed that 136 out of 199 compounds followed Lipinski's rule. The bioavailability radar determined that 71 of these phytoconstituents had good oral bioavailability. Overall, the study indicates that the phytoconstituents that were found to have a shedload of pharmacological potential. The overall study showed that identified potential phytochemical compounds with pharmaceutical values, showing promise for drug development.

Green synthesized silicon dioxide nanoparticles (SiO2NPs) ameliorated the cadmium toxicity in melon by regulating antioxidant enzymes activity and stress-related genes expression

Green synthesized nanoparticles (NPs) are an eco-friendly and cost-effective approach to reduce heavy metal stress in plants. Among heavy metals, cadmium (Cd) possesses higher toxicity to the crops and ultimately reduces their growth and yield. The current study aims to evaluate the effectiveness of green synthesized SiO2NPs to reduce toxic effects of Cd in melon (Cucumis melo) by regulating physiological parameters, enhancing antioxidant enzyme activity, and modulating stress-related gene expression. The SiO2NPs were synthesized using Artemisia annua plant extract having spherical shape and size within the range of 40-70 nm and characterized using advanced spectroscopic and analytical techniques. The application of SiO2NPs (75 mg/L) significantly improved physiological parameters such as shoot length (SL), root length (RL), leaf fresh weight (LFW), root fresh weight (RFW), leaf dry weight (LDW) and root dry weight (RDW) by 14%, 20%, 15%, 16%, 14%, and 28%, respectively, compared to Cd-stressed plants. Photosynthetic pigments (chlorophyll and carotenoids) showed a notable increase of 15% and 40%, respectively. Furthermore, the activities of antioxidant enzymes such as SOD, POD, CAT, and APX were enhanced by 28.67%, 35.45%, 32.07%, and 42.75%, respectively. In addition, applying SiO2NPs increased the concentration of macronutrients N, P, and K by 33%, 40%, and 37%, respectively, compared to Cd-stressed plants. Moreover, SiO2NPs upregulated the expression of several stress-related genes and reduced Cd accumulation in shoots and roots. This study reveals that green synthesized SiO2NPs effectively reduced the Cd toxicity in melon by improving morphological and physiological parameters, enhancing antioxidant enzyme activity, and regulating the expression of stress-related genes. These findings suggest that green synthesized SiO2NPs could play a crucial role in sustainable agriculture by protecting crops from heavy metal stress.

Nanoparticles: a promising tool against environmental stress in plants

With a focus on plant tolerance to environmental challenges, nanotechnology has emerged as a potent instrument for assisting crops and boosting agricultural production in the face of a growing worldwide population. Nanoparticles (NPs) and plant systems may interact molecularly to change stress response, growth, and development. NPs may feed nutrients to plants, prevent plant diseases and pathogens, and detect and monitor trace components in soil by absorbing their signals. More excellent knowledge of the processes of NPs that help plants survive various stressors would aid in creating more long-term strategies to combat these challenges. Despite the many studies on NPs' use in agriculture, we reviewed the various types of NPs and their anticipated molecular and metabolic effects upon entering plant cells. In addition, we discussed different applications of NPs against all environmental stresses. Lastly, we introduced agricultural NPs' risks, difficulties, and prospects.

Nanoscale materials and NO-ROS homeostasis in plants: trilateral dynamics

Nanoparticles (NPs) have garnered increasing attention for their applications in agriculture and plant science, particularly for their interactions with reactive oxygen species (ROS) and nitric oxide (•NO). NPs, owing to their novel physicochemical properties, can be used to uniquely modulate ROS levels, enabling great control over redox homeostasis and signaling cascades. In addition, NPs may act as carriers for •NO donors, thus facilitating controlled and synchronized release and targeted delivery of •NO within plant systems. This opinion article provides insights into the current state of knowledge regarding NP interactions with ROS and •NO homeostasis in plants, highlighting key findings and knowledge gaps, as well as outlining future research directions in this rapidly expanding and potentially transformative field of research.

Ameliorating the detrimental effects of chromium in wheat by silicon nanoparticles and its enriched biochar

Increased anthropogenic activities over the last decades have led to a gradual increase in chromium (Cr) content in the soil, which, due to its high mobility in soil, makes Cr accumulation in plants a serious threat to the health of animals and humans. The present study investigated the ameliorative effect of foliar-applied Si nanoparticles (SiF) and soil-applied SiNPs enriched biochar (SiBc) on the growth of wheat in Cr-polluted soil (CPS). Two levels of CPS were prepared, including 12.5 % and 25 % by adding Cr-polluted wastewater in the soil as soil 1 (S1) and soil 2 (S2), respectively for the pot experiment with a duration of 40 days. Cr stress significantly reduced wheat growth, however, combined application of SiF and SiBc improved root and shoot biomass production under Cr stress by (i) reducing Cr accumulation, (ii) increasing activities of antioxidant enzymes (ascorbate peroxidase and catalase), and (iii) increasing protein and total phenolic contents in both root and shoot respectively. Nonetheless, separate applications of SiF and SiBc effectively reduced Cr toxicity in shoot and root respectively, indicating a tissue-specific regulation of wheat growth under Cr. Later, the Langmuir and Freundlich adsorption isotherm analysis showed a maximum soil Cr adsorption capacity ∼ Q(max) of 40.6 mg g-1 and 59 mg g-1 at S1 and S2 respectively, while the life cycle impact assessment showed scores of -1 mg kg-1 and -211 mg kg-1 for Cr in agricultural soil and - 0.184 and - 38.7 for human health at S1 and S2 respectively in response to combined SiF + SiBC application, thus indicating the environment implication of Si nanoparticles and its biochar in ameliorating Cr toxicity in different environmental perspectives.

Magnetic Resonance Imaging-Based Monitoring of the Accumulation of Polyethylene Terephthalate Nanoplastics

Polyethylene terephthalate (PET) is one of the most produced plastic materials in the world. The emergence of microplastics and nanoplastics (MPs/NPs) as a significant environmental contaminant has become a matter of increasing concern. While the toxicological effects of PET NPs have been widely researched, there is a lack of methodologies for studying their accumulation. The present study introduces a novel method to monitor the distribution of PET NPs in germinating wheat (Triticum aestivum L.) seeds. This involves the functionalization of superparamagnetic iron oxide nanoparticles (SPIONs) with PET NPs (PET-fSPIONs) coupled with magnetic resonance microimaging (µMRI) to provide insight into their distribution within the seed. The present study has demonstrated that PET-fSPIONs accumulate in specific regions of germinating wheat seeds, including the shoot apical meristem, the radicle, the coleoptile, the plumule, and the scutellum. Furthermore, the accumulation of PET-fSPIONs has been shown to exert a discernible effect on spin-spin relaxation (T2), as observed via MRI and quantitative T2 relaxation time analysis. The accumulation of PET NPs in embryo regions was also confirmed by SEM. Diffusion-weighted magnetic resonance imaging (DW-MRI) and non-invasive chemical shift imaging analyses demonstrated that PET NPs resulted in restricted diffusion within the highlighted areas, as well as an impact on lipid content. Our study reveals that using µMRI with fSPIONs provides a non-invasive method to monitor the biodistribution of PET nanoparticles in wheat seeds. Additionally, it offers valuable insights into the microstructural interactions of PET.

Harnessing plant extracts for eco-friendly synthesis of iron nanoparticle (Fe-NPs): Characterization and their potential applications for ameliorating environmental pollutants

Iron-nanoparticles (Fe-NPs) are increasingly been utilized in environmental applications due to their efficacy and strong catalytic activities. The novelty of nanoparticle science had attracted many researchers and especially for their green synthesis, which can effectively reuse biological resources during the polymerization reactions. Thus, the synthesis of Fe-NPs utilizing plant extracts could be considered as the eco-friendly, simple, rapid, energy-efficient, sustainable, and cost-effective. The green synthesis route can be recognized as a practical, valuable, and economically effective alternative for large-scale production. During the production process, some biomolecules present in the extracts undergo metal salts reduction, which can serve as both a capping and reducing mechanism, enhancing the reactivity and stability of green-synthesized Fe-NPs. The diversity of species provided a wide range of potential sources for green synthesis of Fe-NPs. With improved understanding of the specific biomolecules involved in the bioreduction and stabilization processes, it will become easier to identify and utilize new, potential plant materials for Fe-NPs synthesis. Newly synthesized Fe-NPs require different characterization techniques such as transmission electron microscope, ultraviolet-visible spectrophotometry, and X-ray absorption fine structure, etc, for the determination of size, composition, and structure. This review described and assessed the recent advancements in understanding green-synthesized Fe-NPs derived from plant-based material. Detailed information on various plant materials suitable of yielding valuable biomolecules with potential diverse applications in environmental safety. Additionally, this review examined the characterization techniques employed to analyze Fe-NPs, their stability, accumulation, mobility, and fate in the environment. Holistically, the review assessed the applications of Fe-NPs in remediating wastewaters, organic residues, and inorganic contaminants. The toxicity of Fe-NPs was also addressed; emphasizing the need to refine the synthesis of green Fe-NPs to ensure safety and environmental friendliness. Moving forward, the future challenges and opportunities associated with the green synthesis of Fe-NPs would motivate novel research about nanoparticles in new directions.

Carbon Nanodot-Microbe-Plant Nexus in Agroecosystem and Antimicrobial Applications

The intensive applications of nanomaterials in the agroecosystem led to the creation of several environmental problems. More efforts are needed to discover new insights in the nanomaterial-microbe-plant nexus. This relationship has several dimensions, which may include the transport of nanomaterials to different plant organs, the nanotoxicity to soil microbes and plants, and different possible regulations. This review focuses on the challenges and prospects of the nanomaterial-microbe-plant nexus under agroecosystem conditions. The previous nano-forms were selected in this study because of the rare, published articles on such nanomaterials. Under the study's nexus, more insights on the carbon nanodot-microbe-plant nexus were discussed along with the role of the new frontier in nano-tellurium-microbe nexus. Transport of nanomaterials to different plant organs under possible applications, and translocation of these nanoparticles besides their expected nanotoxicity to soil microbes will be also reported in the current study. Nanotoxicity to soil microbes and plants was investigated by taking account of morpho-physiological, molecular, and biochemical concerns. This study highlights the regulations of nanotoxicity with a focus on risk and challenges at the ecological level and their risks to human health, along with the scientific and organizational levels. This study opens many windows in such studies nexus which are needed in the near future.

Potassium silica nanostructure improved growth and nutrient uptake of sorghum plants subjected to drought stress

Introduction

Recent advancements in nanotechnology present promising opportunities for enhancing crop resilience in adverse environmental conditions.

Methods

In this study, we conducted a factorial experiment to investigate the influence of potassium nanosilicate (PNS) on sorghum plants exposed to varying degrees of drought stress A randomized complete block design with three replications was employed to subject the sorghum plants to different drought conditions. The three levels of stress were designated as non-stress (NS at -0.03 MPa), moderate stress (MD at -0.6 MPa), and severe stress (SD at -1.2 MPa). The plants were administered PNS at concentrations of 0 mM (control), 3.6 mM Si, and 7.2 mM Si.

Results and discussion

As drought stress intensified, we observed significant reductions in multiple plant parameters, including height, fresh weight, dry weight, leaf number, stem diameter, cluster length, seed weight, and nutrient uptake, with the most pronounced effects observed under SD conditions. Interestingly, nitrogen (N) and potassium (K) levels exhibited an increase under drought stress and PNS application, peaking at MD, alongside Si concentrations. Notably, PNS application facilitated enhanced nutrient uptake, particularly evident in the significant increase in nitrogen concentration observed at 3.6 mM PNS. Furthermore, the application of PNS significantly enhanced the fresh weight and nutrient concentrations (notably K and Si) in sorghum seeds under drought stress, despite varying statistical significance for other nutrients. These findings shed light on the mechanisms through which PNS exerts beneficial effects on plant performance under drought stress. By elucidating the complex interactions between PNS application, drought stress, and plant physiology, this study contributes significantly to the development of sustainable agricultural practices aimed at bolstering crop resilience and productivity in water-limited environments.

Agriculture and environmental management through nanotechnology: Eco-friendly nanomaterial synthesis for soil-plant systems, food safety, and sustainability

Through the advancement of nanotechnology, agricultural and food systems are undergoing strategic enhancements, offering innovative solutions to complex problems. This scholarly essay thoroughly examines nanotechnological innovations and their implications within these critical industries. Traditional practices are undergoing radical transformation as nanomaterials emerge as novel agents in roles traditionally filled by fertilizers, pesticides, and biosensors. Micronutrient management and preservation techniques are further enhanced, indicating a shift towards more nutrient-dense and longevity-oriented food production. Nanoparticles (NPs), with their unique physicochemical properties, such as an extraordinary surface-to-volume ratio, find applications in healthcare, diagnostics, agriculture, and other fields. However, concerns about their potential overuse and bioaccumulation raise unanswered questions about their health effects. Molecule-to-molecule interactions and physicochemical dynamics create pathways through which nanoparticles cause toxicity. The combination of nanotechnology and environmental sustainability principles leads to the examination of green nanoparticle synthesis. The discourse extends to how nanomaterials penetrate biological systems, their applications, toxicological effects, and dissemination routes. Additionally, this examination delves into the ecological consequences of nanomaterial contamination in natural ecosystems. Employing robust risk assessment methodologies, including the risk allocation framework, is recommended to address potential dangers associated with nanotechnology integration. Establishing standardized, universally accepted guidelines for evaluating nanomaterial toxicity and protocols for nano-waste disposal is urged to ensure responsible stewardship of this transformative technology. In conclusion, the article summarizes global trends, persistent challenges, and emerging regulatory strategies shaping nanotechnology in agriculture and food science. Sustained, in-depth research is crucial to fully benefit from nanotechnology prospects for sustainable agriculture and food systems.

Zinc oxide nanoparticles influence on plant tolerance to salinity stress: insights into physiological, biochemical, and molecular responses

A slight variation in ecological milieu of plants, like drought, heavy metal toxicity, abrupt changes in temperature, flood, and salt stress disturbs the usual homeostasis or metabolism in plants. Among these stresses, salinity stress is particularly detrimental to the plants, leading to toxic effects and reduce crop productivity. In a saline environment, the accumulation of sodium and chloride ions up to toxic levels significantly correlates with intracellular osmotic pressure, and can result in morphological, physiological, and molecular alterations in plants. Increased soil salinity triggers salt stress signals that activate various cellular-subcellular mechanisms in plants to enable their survival in saline conditions. Plants can adapt saline conditions by maintaining ion homeostasis, activating osmotic stress pathways, modulating phytohormone signaling, regulating cytoskeleton dynamics, and maintaining cell wall integrity. To address ionic toxicity, researchers from diverse disciplines have explored novel approaches to support plant growth and enhance their resilience. One such approach is the application of nanoparticles as a foliar spray or seed priming agents positively improve the crop quality and yield by activating germination enzymes, maintaining reactive oxygen species homeostasis, promoting synthesis of compatible solutes, stimulating antioxidant defense mechanisms, and facilitating the formation of aquaporins in seeds and root cells for efficient water absorption under various abiotic stresses. Thus, the assessment mainly targets to provide an outline of the impact of salinity stress on plant metabolism and the resistance strategies employed by plants. Additionally, the review also summarized recent research efforts exploring the innovative applications of zinc oxide nanoparticles for reducing salt stress at biochemical, physiological, and molecular levels.

Silicon nanoparticles vs trace elements toxicity: Modus operandi and its omics bases

Phytotoxicity of trace elements (commonly misunderstood as 'heavy metals') includes impairment of functional groups of enzymes, photo-assembly, redox homeostasis, and nutrient status in higher plants. Silicon nanoparticles (SiNPs) can ameliorate trace element toxicity. We discuss SiNPs response against several essential (such as Cu, Ni, Mn, Mo, and Zn) and non-essential (including Cd, Pb, Hg, Al, Cr, Sb, Se, and As) trace elements. SiNPs hinder root uptake and transport of trace elements as the first line of defence. SiNPs charge plant antioxidant defence against trace elements-induced oxidative stress. The enrolment of SiNPs in gene expressions was also noticed on many occasions. These genes are associated with several anatomical and physiological phenomena, such as cell wall composition, photosynthesis, and metal uptake and transport. On this note, we dedicate the later sections of this review to support an enhanced understanding of SiNPs influence on the metabolomic, proteomic, and genomic profile of plants under trace elements toxicity.

Preparation and characterization of green silicon nanoparticles and their effects on growth and lead (Pb) accumulation in maize (Zea mays L.)

The excessive accumulation of heavy metals, particularly lead (Pb) in agricultural soils, is a growing problem worldwide and needs urgent attention. This study aimed to prepare green silicon (Si) NPs using extract of Chenopodium quinoa leaves and evaluated their effects on Pb uptake and growth of maize (Zea mays L.). The results indicated that Pb exposure negatively affected the growth and chlorophyll contents of maize varieties, while SiNPs positively affected these attributes. Pb alone increased the electrolyte-leakage (EL), hydrogen-peroxide (H2O2) and selected antioxidant enzyme activities in leaves, whereas SiNPs decreased EL and H2O2 concentrations and further enhanced the enzyme activities as compared to their respective treatments without SiNPs. Pb-only treatments led to an increase in Pb concentrations and total Pb uptake in both shoots and roots. In contrast, SiNPs resulted in reduced Pb concentrations, with a concurrent decrease in total Pb uptake in shoots compared to the control treatment. The findings demonstrated that foliar application of SiNPs can mitigate the toxic effects of Pb in maize plants by triggering the antioxidant enzyme system and reducing the oxidative stress. Taken together, SiNPs have the potential to enhance maize production in Pb-contaminated soils. However, future research and application efforts should prioritize key aspects such as optimizing NPs synthesis, understanding positive mechanisms of green-synthesized NPs, and conducting multiple crop tests and real-world field trials.

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.

Silicon dioxide nanoparticles enhance plant growth, photosynthetic performance, and antioxidants defence machinery through suppressing chromium uptake in Brassica napus L

Chromium (Cr) is a highly toxic heavy metal that is extensively released into the soil and drastically reduces plant yield. Silicon nanoparticles (Si NPs) were chosen to mitigate Cr toxicity due to their ability to interact with heavy metals and reduce their uptake. This manuscript explores the mechanisms of Cr-induced toxicity and the potential of Si NPs to mitigate Cr toxicity by regulating photosynthesis, oxidative stress, and antioxidant defence, along with the role of transcription factors and heavy metal transporter genes in rapeseed (Brassica napus L.). Rapeseed plants were grown hydroponically and subjected to hexavalent Cr stress (50 and 100 μM) in the form of K2Cr2O7 solution. Si NPs were foliar sprayed at concentrations of 50, 100 and 150 μM. The findings showed that 100 μM Si NPs under 100 μM Cr stress significantly increased the leaf Si content by 169% while reducing Cr uptake by 92% and 76% in roots and leaves, respectively. The presence of Si NPs inside the plant leaf cells was confirmed by using energy-dispersive spectroscopy, inductively coupled plasma‒mass spectrometry, and confocal laser scanning microscopy. The study's findings showed that Cr had adverse effects on plant growth, photosynthetic gas exchange attributes, leaf mesophyll ultrastructure, PSII performance and the activity of enzymatic and nonenzymatic antioxidants. However, Si NPs minimized Cr-induced toxicity by reducing total Cr accumulation and decreasing oxidative damage, as evidenced by reduced ROS production (such as H2O2 and MDA) and increased enzymatic and nonenzymatic antioxidant activities in plants. Interestingly, Si NPs under Cr stress effectively increased the NPQ, ETR and QY of PSII, indicating a robust protective response of PSII against stress. Furthermore, the enhancement of Cr tolerance facilitated by Si NPs was linked to the upregulation of genes associated with antioxidant enzymes and transcription factors, alongside the concurrent reduction in metal transporter activity.

Silicon nanoparticles confer hypoxia tolerance in citrus rootstocks by modulating antioxidant activities and carbohydrate metabolism

Citrus is a remarkable fruit crop, extremely sensitive to flooding conditions, which frequently trigger hypoxia stress and cause severe damage to citrus plants. Silicon nanoparticles (SiNPs) are beneficial and have the potential to overcome this problem. Therefore, the present study aimed to investigate the effect of silicon nanoparticles to overcome hypoxia stress through modulating antioxidant enzyme activity and carbohydrate metabolism. Three citrus rootstocks (Carrizo citrange, Roubidoux, and Rich 16-6) were exposed to flooding (with and without oxygen) through different SiNP treatments via foliar and root zone. SiNPs applied treatment plants showed a significant increase in photosynthesis, leaf greenness, antioxidant enzymes, and carbohydrate metabolic activities, besides the higher accumulation of proline and glycine betaine. The rate of lipid peroxidation was drastically higher in flooded plants; however, SiNPs application reduced it significantly, ultimately reducing oxidative damage. Overall, Rich16-6 rootstock showed good performance via root zone application compared to other rootstocks, possibly due to genotypical variation in silicon uptake. Our outcomes demonstrate that SiNPs significantly affect plant growth during hypoxia stress conditions, and their use is an optimal strategy to overcome this issue. This study laid the foundation for future research to use at the commercial level to overcome hypoxia stress and a potential platform for future research.

Enhanced ultraviolet-B radiation alleviates structural damages on rice leaf caused by Magnaporthe oryzae infection

Enhanced ultraviolet-B (UV-B) radiation can change the interaction between crops and pathogens. The effects of single and compound stresses of enhanced UV-B radiation (5.0 kJ·m-2) and Magnaporthe oryzae on the morphology, anatomy, and ultrastructure of rice leaves were investigated. M. oryzae infection decreased the leaf area and thickness, reduced the stomatal area and density, and caused damages to the leaf ultrastructure, such as cytoplasm-cell wall separation, atrophy and sinking of fan-shaped bulliform cells, and chloroplast deformation. The enhanced UV-B radiation supplied before or during M. oryzae infection remarkably decreased the mycelia number of M. oryzae in leaf epidermis, increased the leaf area, leaf thickness, stomatal density, and mastoid number; and alleviated the ultrastructural damages induced by M. oryzae to keep an integral chloroplast. While the UV-B radiation was supplied after M. oryzae infection, its alleviation effects on the damages induced by M. oryzae infection on the morphology and structure of rice leaf were attenuated. Thus, the alleviation of enhanced UV-B radiation on damages induced by M. oryzae infection on rice leaves was related to its application period. The enhanced UV-B radiation supplied before or during M. oryzae infection allowed the rice leaf to resist M. oryzae infection.

Update on the state of research to manage Fusarium head blight

Fusarium head blight (FHB) is one of the most devastating diseases of cereal crops, causing severe reduction in yield and quality of grain worldwide. In the United States, the major causal agent of FHB is the mycotoxigenic fungus, Fusarium graminearum. The contamination of grain with mycotoxins, including deoxynivalenol and zearalenone, is a particularly serious concern due to its impact on the health of humans and livestock. For the past few decades, multidisciplinary studies have been conducted on management strategies designed to reduce the losses caused by FHB. However, effective management is still challenging due to the emergence of fungicide-tolerant strains of F. graminearum and the lack of highly resistant wheat and barley cultivars. This review presents multidisciplinary approaches that incorporate advances in genomics, genetic-engineering, new fungicide chemistries, applied biocontrol, and consideration of the disease cycle for management of FHB.

Modulation of metal transporters, oxidative stress and cell abnormalities by synergistic application of silicon and titanium oxide nanoparticles: A strategy for cadmium tolerance in rice

Heavy metals, especially cadmium (Cd), cause severe toxicity symptoms in crop plants. Applying nanoparticles (NPs) as nano-fertilizers is a novel approach to mitigating plants' Cd stress. However, knowledge about the combinational use of silicon (Si) and titanium dioxide (TiO2) NPs to mitigate Cd stress, especially in rice, must be highlighted. TiO2-NPs (15 mg L-1) and Si-NPs (2.5 mM) were applied alone and in combination to rice plants grown without (control; no Cd stress) and with (100 μM) Cd concentration. Results revealed that compared to the control plants, root length, shoot length, shoot fresh weight, and root dry weight of rice seedlings were significantly decreased by 25.43%, 26.64%, 34.13%, and 29.87% under Cd exposure. However, the synergistic effect of TiO2- and Si-NPs increased rice plants' shoot length, root length, root dry weight, and shoot fresh weight by 24.62%, 29.81%, 36.16%, and 33.07%, respectively, under the Cd-toxicity. The concentration of malondialdehyde (MDA) and H2O2 were amplified due to Cd stress, which leads to damage to the subcellular structures. Si and TiO2-NPs co-application improved the anti-oxidative enzymatic activities (catalase, peroxidase, superoxide dismutase) and an elevated concentration of non-enzymatic glutathione in Cd-exposed rice. The Cd accumulation was condensed by 21.37% and 19.7% in the shoot, while 48.31% and 45.65% in root tissues under Si-NPs + Cd and TiO2-NPs + Cd treatments compared to Cd-alone treated seedlings, respectively. The expression patterns of metal transporters, such as OsNramp1 and OsHMA3, were the highest when rice plants were cultivated under Cd stress and significantly reduced when treated with sole and combined Si- and TiO2-NPs treatments. In conclusion, combining Si- and TiO2-NPs significantly improved the antioxidant enzymatic activities, chlorophyll contents, biomass production, and reduced cellular damage. Despite limitations, our findings guide future research, addressing risks, optimizing concentrations, and assessing long-term effects that can balance agricultural progress with environmental sustainability.

Silicon-based nanoparticles for mitigating the effect of potentially toxic elements and plant stress in agroecosystems: A sustainable pathway towards food security

Due to their size, flexibility, biocompatibility, large surface area, and variable functionality nanoparticles have enormous industrial, agricultural, pharmaceutical and biotechnological applications. This has led to their widespread use in various fields. The advancement of knowledge in this field of research has altered our way of life from medicine to agriculture. One of the rungs of this revolution, which has somewhat reduced the harmful consequences, is nanotechnology. A helpful ingredient for plants, silicon (Si), is well-known for its preventive properties under adverse environmental conditions. Several studies have shown how biogenic silica helps plants recover from biotic and abiotic stressors. The majority of research have demonstrated the benefits of silicon-based nanoparticles (Si-NPs) for plant growth and development, particularly under stressful environments. In order to minimize the release of brine, heavy metals, and radioactive chemicals into water, remove metals, non-metals, and radioactive components, and purify water, silica has also been used in environmental remediation. Potentially toxic elements (PTEs) have become a huge threat to food security through their negative impact on agroecosystem. Si-NPs have the potentials to remove PTEs from agroecosystem and promote food security via the promotion of plant growth and development. In this review, we have outlined the various sources and ecotoxicological consequences of PTEs in agroecosystems. The potentials of Si-NPs in mitigating PTEs were extensively discussed and other applications of Si-NPs in agriculture to foster food security were also highlighted.

Molecular Effects of Silicon on Arabidopsis thaliana Seedlings under UV-B Stress

Silicon-plant interaction studies have shown that silicon reduces the harmful effects of stress in plants. Ultraviolet-B (UV-B) radiation, one of the abiotic stress affecting plants, poses a severe problem due to global warming. In this context, it is crucial to examine silicon's effects on UV-B radiation stress at the molecular level. The experiments were carried out on 17 days old Arabidopsis seedlings that were treated with 800 μWatt cm-2 doses of UV-B for 60 min and harvested on the 28th day. 1 mM orthosilicic acid was applied to the in vitro plant tissue culture for experimental groups. According to the results of the osmolyte accumulation analyses, silicon has been shown to play a role in the osmotic stress response. Gene expression levels of DGK2, CHS, FLC, RAD51, and UVR8 were measured via qPCR, and it has been shown that silicon interacts with these genes under UV-B radiation stress. The result of genomic DNA methylation analysis demonstrated that silicon might affect DNA methylation levels by increasing the 5-mC percentage compared with the control group. This study focused on the molecular effects of silicon application. It supports silicon-plant interaction research by demonstrating that silicon might affect UV-B response at the molecular level.

Unleashing the potential of nanoparticles on seed treatment and enhancement for sustainable farming

The foremost challenge in farming is the storage of seeds after harvest and maintaining seed quality during storage. In agriculture, studies showed positive impacts of nanotechnology on plant development, seed storage, endurance under various types of stress, detection of seed damages, and seed quality. Seed's response varies with different types of nanoparticles depending on its physical and biochemical properties and plant species. Herein, we aim to cover the impact of nanoparticles on seed coating, dormancy, germination, seedling, nutrition, plant growth, stress conditions protection, and storage. Although the seed treatment by nanopriming has been shown to improve seed germination, seedling development, stress tolerance, and seedling growth, their full potential was not realized at the field level. Sustainable nano-agrochemicals and technology could provide good seed quality with less environmental toxicity. The present review critically discusses eco-friendly strategies that can be employed for the nanomaterial seed treatment and seed enhancement process to increase seedling vigor under different conditions. Also, an integrated approach involving four innovative concepts, namely green co-priming, nano-recycling of agricultural wastes, nano-pairing, and customized nanocontainer storage, has been proposed to acclimatize nanotechnology in farming.

Combined application of SiO2 and TiO2 nanoparticles enhances growth characters, physiological attributes and essential oil production of Coleus aromatics Benth

Nanoparticles (NPs) have gained considerable interest among researchers in the field of plant biology, particularly in the agricultural sector. Among the numerous NPs, the individual application of silicon (Si) or titanium (Ti), in their oxide forms, had a positive influence on growth, physiochemical and yield attributes of plants. However, the synergetic application of both these NPs has not been studied yet. Therefore, the current study was aimed to investigate the effect of combined application of silicon dioxide (SiO2) and titanium dioxide (TiO2) NPs on the growth characters, physiological parameters, and essential oil quality and production of Coleus aromatics Benth. Aqueous solutions of nanoparticles were applied to the foliage of the plants at varying combinations (Si50+Ti50, Si100+Ti50, Si100+Ti100, Si200+Ti100, Si100+Ti200 and Si200+Ti200 mg L-1). Various morpho-physiological, biochemical and yield attributes were assessed at 120 days after planting. The results demonstrated that both Si and Ti NPs improved the growth and photosynthetic efficiency in a dose dependent manner. The best results were obtained by the combined application of Si100+Ti100 mg L-1, and thereafter, the values declined progressively. The maximum improvement in fresh weight (39.5 %) and dry weight (40.8 %) of shoot, fresh weight (45.7 %) and dry weight (49.4 %) of root was observed as compared to respective controls. Moreover, the exogenous application of Si100+Ti100 mg L-1 increased photosynthetic attributes such as total content of chlorophyll (41.7 %), carotenoids (43.7 %), chlorophyll fluorescence (7.1 %), and carbonic anhydrase (23.8 %). All of these contributed to the highest accumulation in the content (129.0 %) and yield (215.5 %) of essential oil (EO), in comparison to the control. Thus, results encouraged the use of SiO2 and TiO2 NPs to be applied in combined form to boost the essential oil production of Coleus aromaticus. The findings of this study may serve agronomists to determine the optimal concentrations of NPs for enhanced production of bioactive compounds with a wide range of industrial applications.

Silica nanoparticle accumulation in plants: current state and future perspectives

With their excellent biocompatibility, adjustable size, and high specific surface area, silica nanoparticles (SiO2 NPs) offer an alternative to traditional bulk fertilizers as a means to promote sustainable agriculture. SiO2 NPs have been shown to promote the growth of plants and to reduce the negative effects of biotic and abiotic stresses, but their bioaccumulation is a crucial factor that has been overlooked in studies of their biological effects. In this review, the techniques to quantify and visualize SiO2 NPs in plants were examined first. We then provide a summary of the current state of knowledge on the accumulation, translocation, and transformation of SiO2 NPs in plants and of the factors (e.g., the physicochemical properties of SiO2 NPs, plant species, application mode, and environmental conditions) that influence SiO2 NP bioaccumulation. The challenges in analyzing NP-plant interactions are considered as well. We conclude by identifying areas for further research that will advance our understanding of NP-plant interactions and thus contribute to more sustainable, eco-friendly, nano-enabled approaches to improving crop nutrient supplies. The information presented herein is important to improve the delivery efficiency of SiO2 NPs for precision and sustainable agriculture and to assess the safety of SiO2 NPs during their application in agriculture.

The microwave-assisted synthesis of silica nanoparticles and their applications in a soy plant culture

A rapid and environmentally friendly synthesis of thermodynamically stable silica nanoparticles (SiO2-NPs) from heating via microwave irradiation (MW) compared to conductive heating is presented, as well as their evaluations in a soy plant culture. The parameters of time and microwave power were evaluated for the optimization of the heating program. Characterization of the produced nanomaterials was obtained from the dynamic light scattering (DLS) and zeta potential analyses, and the morphology of the SiO2-NPs was obtained by transmission electron microcopy (TEM) images. From the proposed synthesis, stable, monodisperse, and amorphous SiO2-NPs were obtained. Average sizes reported by DLS and TEM techniques were equal to 11.6 nm and 13.8 nm, respectively. The water-stable suspension of SiO2-NPs shows a zeta potential of -31.80 mV, and the homogeneously spheroidal morphology observed by TEM corroborates with the low polydispersity values (0.300). Additionally, the TEM with fast Fourier transform (FFT), demonstrates the amorphous characteristic of the nanoparticles. The MW-based synthesis is 30 times faster, utilizes 4-fold less reagents, and is ca. 18-fold cheaper than conventional synthesis through conductive heating. After the synthesis, the SiO2-NPs were added to the soil used for the cultivation of soybeans, and the homeostasis for Cu, Ni, and Zn was evaluated through the determination of their total contents by inductively coupled plasma mass spectrometry (ICP-MS) in soy leaves and also through bioimages obtained using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Although the results corroborate through both techniques, they also show the influence of these nanoparticles on the elemental distribution of the leaf surface with altered homeostasis of such elements from both transgenic crops compared to the control group.

Silicate solubilizing and plant growth promoting bacteria interact with biogenic silica to impart heat stress tolerance in rice by modulating physiology and gene expression

Heat stress caused due to increasing warming climate has become a severe threat to global food production including rice. Silicon plays a major role in improving growth and productivity of rice by aiding in alleviating heat stress in rice. Soil silicon is only sparingly available to the crops can be made available by silicate solubilizing and plant-growth-promoting bacteria that possess the capacity to solubilize insoluble silicates can increase the availability of soluble silicates in the soil. In addition, plant growth promoting bacteria are known to enhance the tolerance to abiotic stresses of plants, by affecting the biochemical and physiological characteristics of plants. The present study is intended to understand the role of beneficial bacteria viz. Rhizobium sp. IIRR N1 a silicate solublizer and Gluconacetobacter diazotrophicus, a plant growth promoting bacteria and their interaction with insoluble silicate sources on morpho-physiological and molecular attributes of rice (Oryza sativa L.) seedlings after exposure to heat stress in a controlled hydroponic system. Joint inoculation of silicates and both the bacteria increased silicon content in rice tissue, root and shoot biomass, significantly increased the antioxidant enzyme activities (viz. superoxidase dismutase, catalase and ascorbate peroxidase) compared to other treatments with sole application of either silicon or bacteria. The physiological traits (viz. chlorophyll content, relative water content) were also found to be significantly enhanced in presence of silicates and both the bacteria after exposure to heat stress conditions. Expression profiling of shoot and root tissues of rice seedlings revealed that seedlings grown in the presence of silicates and both the bacteria exhibited higher expression of heat shock proteins (HSPs viz., OsHsp90, OsHsp100 and 60 kDa chaperonin), hormone-related genes (OsIAA6) and silicon transporters (OsLsi1 and OsLsi2) as compared to seedlings treated with either silicates or with the bacteria alone. The results thus reveal the interactive effect of combined application of silicates along with bacteria Rhizobium sp. IIRR N1, G. diazotrophicus inoculation not only led to augmented silicon uptake by rice seedlings but also influenced the plant biomass and elicited higher expression of HSPs, hormone-related and silicon transporter genes leading to improved tolerance of seedling to heat stress.

Silicon nanoparticles: Comprehensive review on biogenic synthesis and applications in agriculture

Recent advancements in nanotechnology have opened new advances in agriculture. Among other nanoparticles, silicon nanoparticles (SiNPs), due to their unique physiological characteristics and structural properties, offer a significant advantage as nanofertilizers, nanopesticides, nanozeolite and targeted delivery systems in agriculture. Silicon nanoparticles are well known to improve plant growth under normal and stressful environments. Nanosilicon has been reported to enhance plant stress tolerance against various environmental stress and is considered a non-toxic and proficient alternative to control plant diseases. However, a few studies depicted the phytotoxic effects of SiNPs on specific plants. Therefore, there is a need for comprehensive research, mainly on the interaction mechanism between NPs and host plants to unravel the hidden facts about silicon nanoparticles in agriculture. The present review illustrates the potential role of silicon nanoparticles in improving plant resistance to combat different environmental (abiotic and biotic) stresses and the underlying mechanisms involved. Furthermore, our review focuses on providing the overview of various methods exploited in the biogenic synthesis of silicon nanoparticles. However, certain limitations exist in synthesizing the well-characterized SiNPs on a laboratory scale. To bridge this gap, in the last section of the review, we discussed the possible use of the machine learning approach in future as an effective, less labour-intensive and time-consuming method for silicon nanoparticle synthesis. The existing research gaps from our perspective and future research directions for utilizing SiNPs in sustainable agriculture development have also been highlighted.

Silicon nanoparticles: Synthesis, uptake and their role in mitigation of biotic stress

In the current scenario of global warming and climate change, plants face many biotic stresses, which restrain growth, development and productivity. Nanotechnology is gaining precedence over other means to deal with biotic and abiotic constraints for sustainable agriculture. One of nature's most beneficial metalloids, silicon (Si) shows ameliorative effect against environmental challenges. Silicon/Silica nanoparticles (Si/SiO₂NPs) have gained special attention due to their significant chemical and optoelectronic capabilities. Its mesoporous nature, easy availability and least biological toxicity has made it very attractive to researchers. Si/SiO₂NPs can be synthesised by chemical, physical and biological methods and supplied to plants by foliar, soil, or seed priming. Upon uptake and translocation, Si/SiO₂NPs reach their destined cells and cause optimum growth, development and tolerance against environmental stresses as well as pest attack and pathogen infection. Using Si/SiO₂NPs as a supplement can be an eco-friendly and cost-effective option for sustainable agriculture as they facilitate the delivery of nutrients, assist plants to mitigate biotic stress and enhances plant resistance. This review aims to present an overview of the methods of formulation of Si/SiO₂NPs, their application, uptake, translocation and emphasize the role of Si/SiO₂NPs in boosting growth and development of plants as well as their conventional advantage as fertilizers with special consideration on their mitigating effects towards biotic stress.

Potential Role of Biochar and Silicon in Improving Physio-Biochemical and Yield Characteristics of Borage Plants under Different Irrigation Regimes

Silicon (Si) and biochar (Bc) are key signaling conditioners that improve plant metabolic processes and promote drought tolerance. However, the specific role of their integrative application under water restrictions on economical plants is not yet well understood. Two field experiments throughout 2018/2019 and 2019/2020 were conducted to examine the physio-biochemical modifications and yield attributes of borage plants mediated by Bc (9.52 tons ha^-1) and/or Si (300 mg L^-1) under different irrigation regimes (100, 75, and 50% of crop evapotranspiration). Catalase (CAT) and peroxidase (POD) activity; relative water content, water, and osmotic potential; leaf area per plant and yield attributes; and chlorophyll (Chl) content, Chl_a/chlorophyllide_a (Chlid_a), and Chl_b/Chlid_b were considerably reduced within the drought condition. On the other hand, oxidative biomarkers, as well as organic and antioxidant solutes, were increased under drought, associated with membrane dysfunction, superoxide dismutase (SOD) activation, and osmotic adjustment (OA) capacity as well as a hyperaccumulation of porphyrin intermediates. Supplementation of Bc and Si lessens the detrimental impacts of drought on several plant metabolic processes associated with increasing leaf area and yield attributes. Their application under normal or drought conditions significantly elicited the accumulation of organic and antioxidant solutes as well as the activation of antioxidant enzymes, followed by lessening the formation of free radical oxygen and mitigating oxidative injuries. Moreover, their application maintained water status and OA capacity. Si and/or Bc treatment reduced protoporphyrin, magnesium-protoporphyrin, and protochlorophyllide while increasing Chl_a and Chl_b assimilation and boosting the ratio of Chl_a/Chlid_a and Chl_b/Chlid_b, resulting in a rise in leaf area per plant and yield components following these modifications. These findings highlight the significance of Si and/or Bc as (a) stress-signaling molecule(s) in regulating defensive systems in drought-affected borage plants by boosting antioxidant aptitude, regulating water status, and accelerating chlorophyll assimilation, thus leading to increasing leaf area and productivity.

Effect of deficit irrigation on physiological, biochemical, and yield characteristics in three baby corn cultivars (Zea mays L.)

The main problem in the production of crops in arid and semi-arid regions of the world is the lack of water and its effect on the plant in the form of drought stress. Cultivation of key crops such as corn, which also requires a lot of water, is not possible in these areas except by applying water consumption management methods. Among the most important of these methods is deficit irrigation. The effect of deficit irrigation on relative water content (RWC), malondialdehyde (MDA), compatible osmolytes (proline and soluble sugars), antioxidant enzymes, and yield was studied in three baby corn cultivars in a field experiment using a randomized complete block design (RCBD) with split-plots and three replications. Three levels of deficit irrigation (0, 20, and 40% deficit) constituted the main plots and three cultivars of baby corn (Challenger, Basin, and Passion) constituted the sub plots. Analysis of variance showed that deficit irrigation had a significant effect on all variables. Cultivar (Challenger, Basin and Passion) had a significant effect on proline (0%, 41.5% and 73.2%), carbohydrates (23.9%, 15.4% and 0%), and MDA content (0%, 26.1% and 41.2%), as well as peroxidase (POD) (0%, 136.1% and 227.9%) levels respectively. The interaction between deficit irrigation and cultivar had a significant effect on proline, carbohydrates, and POD. RWC decreased (26.9, 6.5 and 0%) with increasing irrigation deficit (0, 20 and 40%) respectively while proline (0, 23.7 and 64.8%), carbohydrates (0, 29.7 and 34.09%), catalase (CAT) (0, 20.8 and 70.1%), and POD (0, 55.05 and 113.2%) increased under the same conditions. Carbohydrate content was higher in the Basin and Challenger cultivars (21.71 and 19.07) and proline (145.9), POD (193.9), and MDA content (8.53) were higher in the Passion cultivar. Among the studied cultivars, the highest yield was achieved by the Passion cultivar (37.02 and 62.9% more than Challenger and Basin cultivars respectively). In general, the results showed that drought stress caused an increase in compatible osmolyte content and the activity of antioxidant enzymes. However, this increase could not offset the effects of drought stress on yield in the 40% deficit treatment.

The mechanism of silicon on alleviating cadmium toxicity in plants: A review

Cadmium is one of the most toxic heavy metal elements that seriously threaten food safety and agricultural production worldwide. Because of its high solubility, cadmium can easily enter plants, inhibiting plant growth and reducing crop yield. Therefore, finding a way to alleviate the inhibitory effects of cadmium on plant growth is critical. Silicon, the second most abundant element in the Earth's crust, has been widely reported to promote plant growth and alleviate cadmium toxicity. This review summarizes the recent progress made to elucidate how silicon mitigates cadmium toxicity in plants. We describe the role of silicon in reducing cadmium uptake and transport, improving plant mineral nutrient supply, regulating antioxidant systems and optimizing plant architecture. We also summarize in detail the regulation of plant water balance by silicon, and the role of this phenomenon in enhancing plant resistance to cadmium toxicity. An in-depth analysis of literature has been conducted to identify the current problems related to cadmium toxicity and to propose future research directions.

Foliar application of silicon-based nanoparticles improve the adaptability of maize (Zea mays L.) in cadmium contaminated soils

Heavy metals (HMs) especially cadmium (Cd) absorbed by the roots of crop plants like maize have emerged as one of the most serious threats by causing stunted plant growth along with disturbing the photosynthetic machinery and nutrient homeostasis process. A trial was conducted for inducing Cd stress tolerance in maize by exogenous application of silicon nanoparticles (SiNPs) using five doses of SiNPs (0, 100, 200, 300, and 400 ppm) and three levels of Cd (0, 15, and 30 ppm) for maize hybrid (SF-9515). The response variables included morphological traits and biochemical parameters of maize. The results indicated that Cd level of 30 ppm remained the most drastic for maize plants by recording the minimum traits such as shoot length (39.35 cm), shoot fresh weight (9.52 g) and shoot dry weight (3.20 g), leaf pigments such as chlorophyll a (0.55 mg/g FW), chlorophyll b (0.27 mg/g FW), total contents (0.84 mg/g FW), and carotenoid contents (0.19 µg/g FW). Additionally, the same Cd level disrupted biochemical traits such as TSP (4.85 mg/g FW), TP (252.94 nmol/g FW), TSAA (18.92 µmol g^-1 FW), TSS (0.85 mg/g FW), and antioxidant activities such as POD (99.39 min^-1 g^-1 FW), CAT (81.58 min^-1 g^-1 FW), APX (2.04 min^-1 g^-1 FW), and SOD (172.79 min^-1 g^-1 FW). However, a higher level of Cd resulted in greater root length (87.63 cm), root fresh weight (16.43 g), and root dry weight (6.14 g) along with higher Cd concentration in the root (2.52 µg/g^-1) and shoot (0.48 µg/g^-1). The silicon nanoparticles (Si NPs) treatment significantly increased all measured attributes of maize. The highest value was noted of all the parameters such as chlorophyll a (0.91 mg/g FW), chlorophyll b (0.57 mg/g FW), total chlorophyll contents (1.48 mg/g FW), total carotenoid contents (0.40 µg/g FW), TSP (6.12 mg/g FW), TP (384.56 nmol/g FW), TSAA (24.64 µmol g^-1 FW), TSS (1.87 mg/g FW), POD (166.10 min^-1 g^-1 FW), CAT (149.54 min^-1 g^-1 FW), APX (3.49 min^-1 g^-1 FW), and SOD (225.57 min^-1 g^-1 FW). Based on recorded findings, it might be inferred that higher levels of Cd tend to drastically reduce morpho-physiological traits of maize and foliage-applied silver nanoparticles hold the potential to ameliorate the adverse effect of Cd stress on maize.

Silicon nanoparticles (SiNPs) restore photosynthesis and essential oil content by upgrading enzymatic antioxidant metabolism in lemongrass (Cymbopogon flexuosus) under salt stress

Lemongrass (Cymbopogon flexuosus) has great relevance considering the substantial commercial potential of its essential oil. Nevertheless, the increasing soil salinity poses an imminent threat to lemongrass cultivation given its moderate salt-sensitivity. For this, we used silicon nanoparticles (SiNPs) to stimulate salt tolerance in lemongrass considering SiNPs special relevance to stress settings. Five foliar sprays of SiNPs 150 mg L^-1 were applied weekly to NaCl 160 and 240 mM-stressed plants. The data indicated that SiNPs minimised oxidative stress markers (lipid peroxidation, H₂O₂ content) while triggering a general activation of growth, photosynthetic performance, enzymatic antioxidant system including superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), and osmolyte proline (PRO). SiNPs amplified stomatal conductance and photosynthetic CO₂ assimilation rate by about 24% and 21% in NaCl 160 mM-stressed plants. Associated benefits contributed to pronounced plant phenotype over their stressed counterparts, as we found. Foliar SiNPs sprays assuaged plant height by 30% and 64%, dry weight by 31% and 59%, and leaf area by 31% and 50% under NaCl 160 and 240 mM concentrations, respectively. SiNPs relieved enzymatic antioxidants (SOD, CAT, POD) and osmolyte (PRO) in lemongrass plants stressed with NaCl 160 mM (9%, 11%, 9%, and 12%, respectively) and NaCl 240 mM (13%, 18%, 15%, and 23%, respectively). The same treatment supported the oil biosynthesis improving essential oil content by 22% and 44% during 160 and 240 mM salt stress, respectively. We found SiNPs can completely overcome NaCl 160 mM stress while significantly palliating NaCl 240 mM stress. Thus, we propose that SiNPs can be a useful biotechnological tool to palliate salinity stress in lemongrass and related crops.

Morpho-physiological and biochemical response of wheat to various treatments of silicon nano-particles under drought stress conditions

Silicon nanoparticles (Si-NPs) have shown their potential for use in farming under water-deficient conditions. Thus, the experiment was accomplished to explore the impacts of seed priming of Si-NPs on wheat (Triticum aestivum L.) growth and yield under different drought levels. The plants were grown in pots under natural ecological environmental conditions and were harvested on 25th of April, 2020. The results revealed that seed priming of Si-NPs (0, 300, 600, and 900 mg/L) suggestively improved, the spike length, grains per spike, 1000 grains weight, plant height, grain yield, and biological yield by 12-42%, 14-54%, 5-49%, 5-41%, 17-62%, and 21-64%, respectively, relative to the control. The Si-NPs improved the leaf gas trade ascribes and chlorophyll a and b concentrations, though decreased the oxidative pressure in leaves which was demonstrated by the diminished electrolyte leakage and upgrade in superoxide dismutase and peroxidase activities in leaf under Si-NPs remedies over the control. The outcomes proposed that Si-NPs could improve the yield of wheat under a dry spell. In this manner, the utilization of Si-NPs by seed priming technique is a practical methodology for controlling the drought stress in wheat. These findings will provide the basis for future research and helpful to improve the food security under drought and heat related challenges.

Involvement of abscisic acid in silicon-mediated enhancement of copper stress tolerance in Artemisia annua

Heavy metal (HM) toxicity is a well-known hazard which causes deleterious impact on the growth and development of plants. The impact of abscisic acid (ABA) in presence of silicon (Si) on plant development and quality traits has largely gone unexplored. The effects of ABA and Si on the growth, yield, and quality characteristics of Artemisia annua L. plants growing under copper (Cu) stress (20 and 40 mg kg^-1) were investigated in a pot experiment. During this investigation, Cu stress caused severe damage to the plants but exogenous administration of Si and ABA ameliorated the harmful effects of Cu toxicity, and the plants displayed higher biomass and improved physio-biochemical attributes. Copper accumulated in the roots and shoots and its toxicity caused oxidative stress as demonstrated by the increased 2-thiobarbituric acid reactive substance (TBARS) content. It also resulted in the increased activity of antioxidant enzymes, however, the exogenous Si and ABA supplementation decreased the buildup of reactive oxygen species (ROS) and lipid peroxidation, alleviating the oxidative damage produced by HM stress. Copper toxicity had a considerable negative impact on glandular trichome density, ultrastructure as well as artemisinin production. However, combined Si and ABA enhanced the size and density of glandular trichomes, resulting in higher artemisinin production. Taken together, our results demonstrated that exogenous ABA and Si supplementation protect A. annua plants against Cu toxicity by improving photosynthetic characteristics, enhancing antioxidant enzyme activity, protecting leaf structure and integrity, avoiding excess Cu deposition in shoot and root tissues, and helping in enhanced artemisinin biosynthesis. Our results indicate that the combined application of Si and ABA improved the overall growth of plants and may thus be used as an effective approach for the improvement of growth and yield of A. annua in Cu-contaminated soils.

Ethylene Renders Silver Nanoparticles Stress Tolerance in Rice Seedlings by Regulating Endogenous Nitric Oxide Accumulation

Developments in the field of nanotechnology over the past few years have increased the prevalence of silver nanoparticles (AgNPs) in the environment, resulting in increased exposure of plants to AgNPs. Recently, various studies have reported the effect of AgNPs on plant growth at different concentrations. However, identifying the mechanisms and signaling molecules involved in plant responses against AgNPs stress is crucial to find an effective way to deal with the phytotoxic impacts of AgNPs on plant growth and development. Therefore, this study was envisaged to investigate the participation of ethylene in mediating the activation of AgNPs stress tolerance in rice (Oryza sativa L.) through a switch that regulates endogenous nitric oxide (NO) accumulation. Treatment of AgNPs alone hampered the growth of rice seedlings due to severe oxidative stress as a result of decline in sulfur assimilation, glutathione (GSH) biosynthesis and alteration in the redox status of GSH. These results are also accompanied by the higher endogenous NO level. However, addition of ethephon (a donor of ethylene) reversed the AgNP-induced effects. Though the application of silicon nanoparticles (SiNPs) alone promoted the growth of rice seedlings but, interestingly their application in combination with AgNPs enhanced the AgNP-induced toxicity in the seedlings through the same routes as exhibited in the case of AgNPs alone treatment. Interestingly, addition of ethephon reversed the negative effects of SiNPs under AgNPs stress. These results suggest that ethylene might act as a switch to regulate the level of endogenous NO, which in turn could be associated with AgNPs stress tolerance in rice. Furthermore, the results also indicated that addition of l-NG-nitro arginine methyl ester (l-NAME) (an inhibitor of endogenous NO synthesis) also reversed the toxic effects of SiNPs together with AgNPs, further suggesting that the low level of endogenous NO was associated with AgNPs stress tolerance. Overall, the results indicate that the low level of endogenous NO triggers AgNPs stress tolerance, while high level leads to AgNPs toxicity by regulating sulfur assimilation, GSH biosynthesis, redox status of GSH and oxidative stress markers. The results revealed that ethylene might act as a switch for regulating AgNPs stress in rice seedlings by controlling endogenous NO accumulation.

Nanosilicon: An approach for abiotic stress mitigation and sustainable agriculture

Abiotic stresses causing extensive yield loss in various crops globally. Over the past few decades, the application of silicon nanoparticles (nSi) has emerged as one of the abiotic stress mitigators. The initial responses of plants are shown by the biogenesis of reactive oxygen species (ROS) to sustain cellular/organellar integrity to ensure in vivo operation of metabolic functions by regulating physiological and biochemical pathways during stress conditions. Plants have evolved various antioxidative systems to balance/maintain the process of homeostasis via enzymatic and non-enzymatic activities to repair the losses. In the adverse environment, supplementation of Si mitigates the stress condition and improved the growth and development of plants. Its ameliorative effects were correlated with the enhanced antioxidant enzymes activities to maintain the equilibrium between the ROS generation and reduction. However, there are limited studies covered the role of nSi in the abiotic stress condition. This review addresses the accumulation and/or uptake of nSi in several crops and its mode of action linked with improved plants' growth and tolerance capabilities to confer sustainable agriculture.

Elicitation of Bacillus cereus-Amazcala (B.c-A) with SiO2 Nanoparticles Improves Its Role as a Plant Growth-Promoting Bacteria (PGPB) in Chili Pepper Plants

Agriculture needs to decrease the use of agrochemicals due to their high toxicity and adopt new strategies to achieve sustainable food production. Therefore, nanoparticles (NPs) and plant growth-promoting bacteria (PGPB) have been proposed as viable strategies to obtain better crop yields with less environmental impact. Here, we describe the effect of silica nanoparticles (SiO₂-NPs) on survival, antioxidant enzymatic activity, phosphate solubilization capacity, and gibberellin production of Bacillus cereus-Amazcala (B.c-A). Moreover, the effect of the co-application of SiO₂-NPs and B.c-A on seed germination, physiological characteristics, and antioxidant enzymatic activity of chili pepper plants was investigated under greenhouse conditions. The results indicated that SiO₂-NPs at 100 ppm enhanced the role of B.c-A as PGPB by increasing its phosphate solubilization capacity and the production of GA7. Moreover, B.c-A catalase (CAT) and superoxide dismutase (SOD) activities were increased with SiO₂-NPs 100 ppm treatment, indicating that SiO₂-NPs act as a eustressor, inducing defense-related responses. The co-application of SiO₂-NPs 100 ppm and B.c-A improved chili pepper growth. There was an increase in seed germination percentage, plant height, number of leaves, and number and yield of fruits. There was also an increase in CAT and PAL activities in chili pepper plants, indicating that bacteria-NP treatment induces plant immunity.

Foliar-applied nanoscale zero-valent iron (nZVI) and iron oxide (Fe3O4) induce differential responses in growth, physiology, antioxidative defense and biochemical indices in Leonurus cardiaca L

The impacts of nZVI and iron oxides on growth, physiology and elicitation of bioactive antioxidant metabolites in medicinal aromatic plants must be critically assessed to ensure their safe utilization within the food chain and achieve nutritional gains. The present study investigated and compared the morpho-physiological and biochemical changes of Leonurus cardiaca L. plants as affected by various concentrations (0, 250, 500 and 1000 mg L-1) of nZVI and Fe3O4. The foliar uptake of nZVI was verified through Scanning Electron Microscopy (SEM) images and Energy Dispersive X-ray (EDX) analytical spectra. Plants exposed to nZVI at low concentration showed comparatively monotonic deposition of NPs on the surface of leaves, however, the agglomerate size of nZVI was raised as their doses increased, leading to remarkable changes in anatomical and biochemical traits. 250 mg L-1 nZVI and 500 mg L-1 Fe3O4 significantly (P < 0.05) increased plant dry matter accumulation by 37.8 and 27% over the control, respectively. The treatments of nZVI and Fe3O4 at 250 mg L-1 significantly (P < 0.01) improved chlorophyll a content by 22.4% and 15.3% as compared to the control, and then a rapid decrease (by 14.8% and 4.1%) followed at 1000 mg L-1, respectively. Both nZVI and Fe3O4 at 250 mg L-1 had no significant impact on malondialdehyde (MDA) formation, however, at an exposure of 500-1000 mg L-1, the MDA levels and cellular electrolyte leakage were increased. Although nZVI particles could be utilized by plants and enhanced the synthesis of chlorophylls and secondary metabolites, they appeared to be more toxic than Fe3O4 at 1000 mg L-1. Exposure to nZVI levels showed positive, negative and or neutral impacts on leaf water content compared to control, while no significant difference was observed with Fe3O4 treatments. Soluble sugar, total phenolics and hyperoside content were significantly increased upon optimum concentrations of employed treatments-with 250 mg L-1 nZVI being most superior. Among the extracts, those obtained from plants treated with 250-500 mg L-1 nZVI revealed the strong antioxidant activity in terms of scavenging free radical (DPPH) and chelating ferrous ions. These results suggest that nZVI (at lower concentration) has alternative and additional benefits both as nano-fertilizer and nano-elicitor for biosynthesis of antioxidant metabolites in plants, but at high concentrations is more toxic than Fe3O4.

Exogenous nano-silicon application improves ion homeostasis, osmolyte accumulation and palliates oxidative stress in Lens culinaris under NaCl stress

Lentil is one of the highly nutritious legumes but is highly susceptible to salinity stress. Silicon has been known to reduce the effect of various environmental stresses including salinity. Moreover, silicon when applied in its nano-form is expected to augment the beneficial attributes of silicon. However, very little is known regarding the prospect of nano-silicon (nSi) application for alleviating the effect of salinity stress in non-silicified plants like lentil. In this study, the primary objective was to evaluate the efficacy of nSi in the alleviation of NaCl stress during germination and early vegetative stages. In this context, different concentrations of nSi (0, 1, 5, 10 g L-1) was applied along with four different concentrations of NaCl (0, 100, 200, 300 mM). The results indicated the uptake of nSi which was confirmed by the better accumulation of silica in the plant tissues. Most importantly, the enhanced accumulation of silica increased the K+/Na+ ratio of the NaCl-stressed seedlings. Moreover, nSi efficiently improved germination, growth, photosynthetic pigments, and osmotic balance. On the other hand, the relatively reduced activities of antioxidative enzymes were surmounted by the higher activity of non-enzymatic antioxidants which mainly scavenged the increased ROS. Reduced ROS accumulation in return ensured better membrane integrity and reduced electrolyte leakage up on nSi application. Therefore, it can be concluded that the application of nSi (more specifically at 10 g L-1) facilitated the uptake of silica and improved the K+/Na+ ratio to reclaim the growth and physiological status of NaCl-stressed seedlings.

The role of nanoparticles in plant biochemical, physiological, and molecular responses under drought stress: A review

Drought stress (DS) is a serious challenge for sustaining global crop production and food security. Nanoparticles (NPs) have emerged as an excellent tool to enhance crop production under current rapid climate change and increasing drought intensity. DS negatively affects plant growth, physiological and metabolic processes, and disturbs cellular membranes, nutrient and water uptake, photosynthetic apparatus, and antioxidant activities. The application of NPs protects the membranes, maintains water relationship, and enhances nutrient and water uptake, leading to an appreciable increase in plant growth under DS. NPs protect the photosynthetic apparatus and improve photosynthetic efficiency, accumulation of osmolytes, hormones, and phenolics, antioxidant activities, and gene expression, thus providing better resistance to plants against DS. In this review, we discuss the role of different metal-based NPs to mitigate DS in plants. We also highlighted various research gaps that should be filled in future research studies. This detailed review will be an excellent source of information for future researchers to adopt nanotechnology as an eco-friendly technique to improve drought tolerance.

Modulation of physiological and biochemical traits of two genotypes of Rosa damascena Mill. by SiO2-NPs under In vitro drought stress

BACKGROUND

Drought is a major abiotic stress that restricts plant growth and efficiency although some nutrients such as silicon improve drought tolerance by regulating the biosynthesis and accumulating some osmolytes. In this regard, a completely randomized factorial design was performed with three factors including two genotypes ('Maragheh' and 'Kashan'), three concentrations of silicon dioxide nanoparticles (SiO2-NPs) (0, 50, and 100 mg L- 1), and five concentrations of PEG (0, 25, 50, 75, and 100 g L- 1) with three replications.

RESULTS

The findings showed that drought stress decreased protein content and it was improved by SiO2-NPs, so the genotype of 'Maragheh' treated with 100 mg L- 1 SiO2-NPs had the highest protein content. Under severe drought stress, had a higher membrane stability index (MSI) than 'Kashan', and the 'Maragheh' explants subjected to 100 mg L- 1 SiO2-NPs exhibited the uppermost MSI. The explants supplemented with 100 mg L- 1 SiO2-NPs sustained their photosynthetic parameters more in comparison with other treatments under drought stress conditions and as well as 100 mg L- 1 SiO2-NPs showed higher content of protein and proline of 'Maragheh' than 'Kashan'. Drought stress reduced Fm, Fv/Fm, and Fv, while SiO2-NPs treatment enhanced these parameters. SiO2-NPs also improved water deficit tolerance by enhancing the activity of antioxidant enzymes such as catalase (CAT), peroxidase (POD), guaiacol peroxidase (GPX), and superoxide dismutase (SOD) and reducing lipid peroxidation and H2O2 concentration.

CONCLUSIONS

According to the findings, the genotype 'Maragheh' was more tolerance to drought stress than 'Kashan' by improving water balance, antioxidant enzyme activities, and membrane stability as it was obtained from the unpublished previous evaluation in in vivo conditions and we concluded based on these results, in vitro culture can be used for drought screening in Damask rose plants. The results of the current study revealed that the induced drought stress by polyethylene glycol (PEG) in two Damask rose genotypes was ameliorated with SiO2-NPs and the tolerance genotypes were better than the sensitive ones in response to SiO2-NPs treatment.

Application of Exogenous Silicon for Alleviating Photosynthetic Inhibition in Tomato Seedlings under Low−Calcium Stress

To address the low Ca−induced growth inhibition of tomato plants, the mitigation effect of exogenous Si on tomato seedlings under low−Ca stress was investigated using different application methods. We specifically analyzed the effects of root application or foliar spraying of 1 mM Si on growth conditions, leaf photosynthetic properties, stomatal status, chlorophyll content, chlorophyll fluorescence, ATP activity and content, Calvin cycle−related enzymatic activity, and gene expression in tomato seedlings under low vs. adequate calcium conditions. We found that the low−Ca environment significantly affected (reduced) these parameters, resulting in growth limitation. Surprisingly, the application of 1 mM Si significantly increased plant height, stem diameter, and biomass accumulation, protected photosynthetic pigments, improved gas exchange, promoted ATP production, enhanced the activity of Calvin cycle key enzymes and expression of related genes, and ensured efficient photosynthesis to occur in plants under low−Ca conditions. Interestingly, when the same amount of Si was applied, the beneficial effects of Si were more pronounced under low−Ca conditions that under adequate Ca. We speculate that Si might promote the absorption and transport of calcium in plants. The effects of Si also differed depending on the application method; foliar spraying was better in alleviating photosynthetic inhibition in plants under low−Ca stress, whereas root application of Si significantly promoted root growth and development. Enhancing the photosynthetic capacity by foliar Si application is an effective strategy for ameliorating the growth inhibition of plants under low−Ca stress.

Role of Nanoparticles in Enhancing Crop Tolerance to Abiotic Stress: A Comprehensive Review

Plants are subjected to a wide range of abiotic stresses, such as heat, cold, drought, salinity, flooding, and heavy metals. Generally, abiotic stresses have adverse impacts on plant growth and development which affects agricultural productivity, causing food security problems, and resulting in economic losses. To reduce the negative effects of environmental stress on crop plants, novel technologies, such as nanotechnology, have emerged. Implementing nanotechnology in modern agriculture can also help improve the efficiency of water usage, prevent plant diseases, ensure food security, reduce environmental pollution, and enhance sustainability. In this regard, nanoparticles (NPs) can help combat nutrient deficiencies, promote stress tolerance, and improve the yield and quality of crops. This can be achieved by stimulating the activity of certain enzymes, increasing the contents (e.g., chlorophyll) and efficiency of photosynthesis, and controlling plant pathogens. The use of nanoscale agrochemicals, including nanopesticides, nanoherbicides, and nanofertilizers, has recently acquired increasing interest as potential plant-enhancing technologies. This review acknowledges the positive impacts of NPs in sustainable agriculture, and highlights their adverse effects on the environment, health, and food chain. Here, the role and scope of NPs as a practical tool to enhance yield and mitigate the detrimental effects of abiotic stresses in crops are described. The future perspective of nanoparticles in agriculture has also been discussed.

Nanomaterials as an alternative to increase plant resistance to abiotic stresses

The efficient use of natural resources without negative repercussions to the environment has encouraged the incursion of nanotechnology to provide viable alternatives in diverse areas, including crop management. Agriculture faces challenges due to the combination of different abiotic stresses where nanotechnology can contribute with promising applications. In this context, several studies report that the application of nanoparticles and nanomaterials positively affects crop productivity through different strategies such as green synthesis of nanoparticles, plant targeted protection through the application of nanoherbicides and nanofungicides, precise and constant supply of nutrients through nanofertilizers, and tolerance to abiotic stress (e.g., low or high temperatures, drought, salinity, low or high light intensities, UV-B, metals in soil) by several mechanisms such as activation of the antioxidant enzyme system that alleviates oxidative stress. Thus, the present review focuses on the benefits of NPs against these type of stress and their possible action mechanisms derived from the interaction between nanoparticles and plants, and their potential application for improving agricultural practices.