Effect of Three Nanoparticles (Se, Si and Cu) on the Bioactive Compounds of Bell Pepper Fruits under Saline Stress

Detection of Heavy Metal Copper Stress in Apple Rootstocks Using Surface-Enhanced Raman Spectroscopy

Excessive use of copper (Cu) chemicals has led to soil contamination. This study utilized surface-enhanced Raman spectroscopy (SERS) to investigate the effects of 10 commonly encountered concentrations of Cu stress in orchards on apple rootstocks. Spectral preprocessing methods were employed to eliminate baseline drift and fluorescence background interference from the Raman spectra, while data augmentation techniques were incorporated to develop a one-dimensional stacked autoencoder convolutional neural network (1D-SAE-CNN) for classifying Cu stress levels, resulting in evaluation indices greater than 0.9. Scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) quantified Cu distribution in root, stem, and leaf tissues, while micro-Raman imaging visualized lignin, cellulose, and pigments under Cu stress. The results indicate that SERS combined with a deep learning model enables rapid and accurate differentiation of Cu stress levels in apple rootstocks in orchards, while SEM-EDS and micro-Raman imaging techniques reveal the migration effect of Cu2+ within apple rootstock tissues and the ″low concentration promotion, high concentration inhibition″ effect of Cu on apple rootstock growth. Therefore, this approach showcases rapid and accurate detection of heavy metal Cu stress in apple rootstock tissues and has great potential for analyzing various types of heavy metal pollution in agricultural orchard ecosystems.

Optimization of Phytosynthesized Zn-Se Nanocomposites via Response Surface Methodology: Characterization and Germination Impact on Gamma-Irradiated Brassica napus L

The sustainable synthesis and optimization of nanocomposites (NCs) for agricultural applications remains a critical challenge. This study addresses this issue by developing Zn-Se NCs using green synthesis methods with Allium sativa and Mentha arvensis plant extracts optimized via Response Surface Methodology (RSM) to achieve an average size of 34.9 nm. For the first time, the combined application of NCs and gamma irradiation was evaluated to enhance seed viability and early growth in Brassica napus L. in the present study. The results indicated that p-values of 0.0001 and 0.0032 for the linear and quadratic regression models, respectively, were significant. The UV-visible spectrum of Zn-Se NCs showed a sharp peak at 295 nm, while FTIR spectra identified functional groups acting as a reducing agent, detailing their compound class, peak shape, and intensity. Spherical Zn-Se NCs were synthesized with an average size of 34.9 nm. The effects of optimized Zn-Se NCs on germination parameters were assessed, revealing that the percentage germination was non-significant, with a p-value > 0.05. In contrast, the survival rate, seedling length, and seed vigor index (SVI) were significant, with p-values of 0.002, 0.007, and 0.015, respectively. The results demonstrated significant improvements in germination percentage and seedling vigor, highlighting the potential of NCs as a nanobiofertilizer. This study presents a novel green synthesis approach for Zn-Se NCs using Allium sativa and Mentha arvensis plant extracts, achieving precise size control (< 35 nm) through RSM optimization, enhancing bioavailability and eco-friendliness. This study recommends the use of plant-mediated Zn-Se NCs in combination with gamma irradiation as a sustainable and effective approach to improve crop productivity and promote eco-friendly agricultural practices.

Role of Metal-Based Nanoparticles in Capsicum spp. Plants

Agriculture is a core activity in human civilization, constantly facing challenges with the main objective of increasing crop production; to solve this, different strategies and technologies have been used. Currently, metal-based nanoparticles (MNPs) have great potential to be used as agricultural inputs to mitigate the negative effects on crops caused by different stresses. However, studies about their impact on plants and agroecosystems require a comprehensive understanding of their effects. Chili pepper (Capsicum spp.) is a crop of global economic importance that could benefit from the use of MNPs in order to increase its production. The effects of MNPs depend on factors such as their composition, morphology, size, concentration, and application method. Both in vitro and greenhouse studies have demonstrated improvements in plant growth, response to abiotic stresses, and the induction of resistance to different pathogens. However, results vary considerably from one study to another, probably due to heterogeneity in synthesis, characterization, and application methods. This review examines recent findings about the effects of MNPs on chili pepper crops, focusing on growth, development, bioaccumulation, and response to biotic and abiotic stresses.

Green biogenic sulfur nanoparticles enhance Capsicum annuum (L.) resilience to salt stress by triggering physio-biochemical and genetic repair mechanisms

The synthesis of metal nanoparticles is an expanding field of study due to the potential uses in creating new technologies that facilitate the production of crops by improving tolerance against salinity stress. The current study outlined the green synthesis of sulfur nanoparticles (SNPs) using Moringa oleifera (Lam.) leaf extract and its protective role on Capsicum annuum (L.) growth against salinity stress. Using Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction (XRD), the effective formation of the synthesized SNPs was examined and approved. The results confirmed the purity and morphology of SNPs. Then, SNPs (1, 10, 100 mg/l) were used in nano-priming to alleviate the adverse effects of NaCl (50, 100 mM) on C. annuum seedlings. The findings demonstrated that C. annuum growth parameters were severely lowered by increasing salinity stress level, whereas SNPs treatments enhanced plant growth under both salt levels. The optimum concentration for alleviating salinity stress was 10 mg/l SNPs. 10 mg/l SNPs significantly increased shoot fresh weight, dry weight, chlorophyll content, cell membrane stability and relative water content by 75.4, 77.8, 82.5, 89.5 and 20.9%, while reduced the water and solute potential, Na+/K+ ratio, proline, glycine betaine, malondialdehyde, H2O2 and superoxide anion content by 45.5, 43.2, 27.7%, 18.1, 40.3, 39.3, 35.4 and 34.5% respectively compared to untreated stressed control at 100 mM NaCl. Moreover, SNPs substantially improved, antioxidant enzymes activities and upregulated the expression of some salt-tolerant genes under saline conditions. Under both salinity levels, the genes CaHAK6, CaHAK7, CaDHN3, CaCAT1 and CaPOD recorded maximum expression at 10 mg/l SNPs. Overall, these findings demonstrate the efficiency of green SNPs as a practical approach to alleviate NaCl-induced stress in C. annuum plants by triggering many physiological, biochemical and genetic repair mechanisms. These results offer a sustainable agri-environmental strategy for mitigating salt stress and enhancing crop production in saline environments.

Selenium-Containing Nanoformulations Capable of Alleviating Abiotic Stress in Plants

Climate changes cause various types of abiotic stress in plants, thus affecting plant growth and causing decline in yield. An urgent need exists to develop an environmentally friendly attitude based on principles of sustainable agriculture. Nanomaterials may improve plant growth and enhance crop productivity by handling the conditions considered stressful for plants in a sustainable and ecofriendly manner. Selenium (Se) has been put into the category of beneficial elements in plants. Se-enriched crops present a successful choice of dietary resource for Se-supplemented food and feed owing to their high bioavailability and accessibility. Researchers from distinct areas, including both nanoscience and plant science, should encourage emerging innovations that are linked with abiotic stress in crop production. The implementation of Se nanoparticles (SeNPs) is considered one of the predominating mechanisms by plants to ameliorate stressful conditions. Increasing evidence of earlier research revealed that SeNPs could enhance plant growth and development, nutrient bioavailability, soil fertility, and stress response while maintaining environmental safety. Meanwhile, some earlier studies reported that SeNPs might have a multilateral influence on plants dependent on diverse Se nanomaterial traits, doses, and plant species. More efforts are required to enhance the knowledge of how SeNPs impact crops exposed to different abiotic detrimental factors. In light of contemporary research challenges linked to SeNPs and the prolonged application of Se nanomaterials to plants, the aim of this review is elucidating the principal fruitful areas of SeNP exploration, comparisons with bulk Se, insights into mechanisms of abiotic stress alleviation in plants, existing research uncertainties, and practical challenges for SeNP applications under varying environments.

Elucidating the phytotoxic endpoints of sub-chronic exposure to titanium dioxide nanoparticles in Endemic Persian Dracocephalum species

This study was designed to investigate the dichotomous effects of titanium dioxide nanoparticles (TiO2NPs) at varying concentrations (0, 50, 100, 1000, and 2500 ppm) on the physiological, biochemical, and antioxidative defense responses of Persian dragonhead plants cultivated in hydroponic conditions. Over 21 days of treatment, an increase in fresh shoot biomass by 26.2% and plant height by 18.2% was observed at exposure to 50 ppm TiO2NPs. Exposure to 100 ppm NPs negatively affected the biosynthesis of carotenoids, chlorophyll pigments (a, b, and total), and protein content. Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM) analysis revealed TiO2NPs deposition within intercellular spaces and cell walls of root tissues. The physiological stress was prominent in response to 2500 ppm NPs as evidenced by a significant increase in proline and sugar content compared to the control. The enzymatic antioxidative defense was significantly upregulated by the enhanced activity of catalase (CAT) across exposure ranges 100-2500 ppm NPs, ascorbate peroxidase (APX) at 100 and 2500 ppm NPs, and peroxidase (POD) at 100 ppm NPs in plant roots. The antioxidant proficiency was further corroborated by increases in total flavonoids by 30.43% at 2500 ppm, saponins by 253.7%, and iridoids by 22.3% at 100 ppm NPs, relative to control. The results suggest that TiO2NPs fostered growth promotion at sub-lethal doses, and induced adverse biochemical changes at elevated concentrations, prompting the activation of intrinsic defense mechanisms to enhance plant resilience against NPs stresses. The optimal nano-stimulation performance was observed at 50 ppm TiO2NPs, which was suggested for the high yield targets, signifying a potential boon for agricultural productivity.

Eco-Friendly Synthesis of Selenium Nanoparticles via Sternbergia candida: Enhancing Antioxidant Defense and Mitigating Salt Stress in Pepper (Capsicum annuum L.) Plants

Nanoparticles enhance agricultural applications with their bioactivity, bioavailability, and reactivity. Selenium mitigates the adverse effects of salinity on plant growth, boosting antioxidant defense, metabolism, and resilience to abiotic stress. Our study applied selenium nanoparticles to mitigate salinity-induced damage and support plant growth. We characterized green-synthesized nanoparticles and analyzed stress-related metabolites, antioxidant activities (DPPH, ABTS), phenolic content, and reducing powers (CUPRAC, FRAP). Nanoparticle applications reduced proline and MDA levels while boosting chlorophyll, carotenoids, antioxidant activity (DPPH, ABTS), and total phenolic content. An increase was also observed in CUPRAC and FRAP reducing capacities. In terms of phenolic content, the highest value was determined in SA1 (4.58±0.40 mg GAE g-1) application; DPPH free radical scavenging activity IC50 value was determined in A3 (0.13±0.007 mg mL-1) application, which was closest to the positive control. The lowest proline level was found in A3 (15.00±0.64 nmol g-1 FW) and the lowest MDA level was found in SA3 (10.08±0.42 nmol g-1). Comparing the results, green synthesis of selenium nanoparticles using Sternbergia candida (SC-SeNP) at different concentrations showed ameliorative effects on various parameters in plants, and it was determined that the effects of salt stress on pepper plants were reduced following SC-SeNP applications.

Foliar Nutrition Strategies for Enhancing Phenolic and Amino Acid Content in Olive Leaves

Studies on selenium (Se) and silicon (Si) foliar biostimulation of different plants have been shown to affect concentrations of phenolic compounds. However, their effects on olive (Olea europaea L.) primary and secondary metabolites have not been fully investigated. Therefore, the effects of foliar sprayed Si and Se and their combination on the concentration of phenols, selected metabolites involved in the phenol biosynthesis, and mineral elements concentrations were determined in olive leaves of the field-grown cultivar Leccino. During the summer period, leaves were foliar sprayed three times, after which were sampled 30 days after the corresponding application. In general, foliar treatment of Si or Se increased the concentrations of several predominant phenolic compounds, such as oleuropein, oleacein, and specific flavonoids. The effects were especially pronounced after the third application in the harvest time sampling time. Amino acids and other phenol precursors were also significantly affected. The effects were phenol-specific and depended on the treatment, sampling time, and treatment × sampling time interaction. The response of verbascoside to the applied treatments appeared to be closely linked to corresponding changes in its amino acid precursors, such as tyrosine, while its connection with tryptophan and IAA has to be cautiously considered. In contrast, for other phenolic compounds like secoiridoids, a clear interdependence with their precursors was not identified, likely due to the more complex nature of their biosynthesis. The effects on the concentrations of elements other than Se and Si were milder.

Application of oxide nanoparticles mitigates the salt-induced effects on photosynthesis and reduces salt injury in Cyclocarya paliurus

Salinization is very detrimental to photosynthetic processes and plant growth, while nanoparticles (NPs) are considered to be the emerging materials to improve plant adaptability to salt stress. Cyclocarya paliurus is being planted on saline-alkali soils to meet the growing demand for its leaves and medicinal products. However, this species exhibits low salt tolerance and little information is available on whether NPs application would mitigate the salt-induced effects. This study explored the influence of three oxide NPs and their application doses on improving salt tolerance in C. paliurus under simulated natural conditions. The results showed that these oxide NPs could modify the salt tolerance in C. paliurus seedlings, but the alleviating effects varied in the NPs types and their application doses. Under the salt stress, foliar applications of SiO2-NPs with 500 mg L-1 and MnO2-NPs with 50 mg L-1 significantly increased net photosynthetic rate and seedling height by 52.0-59.5 %, and reduced the salt injury index by 67.6-70.7 %. Transcriptomic analysis revealed that the genes related to photosynthesis pathway were well responsive to both salt stress and NPs application, while the applications of high-dose SiO2- and MnO2-NPs up-regulated the expression of 50 photosynthesis-related genes. Weighted gene co-expression network analysis (WGCNA) indicated there existed a close relationship between physiological parameters and gene expression patterns, and the nine key genes in mitigating salt stress in C. paliurus were identified after the NPs application. Our findings suggested that the effects of NPs on mitigating salt-induced damages depending on the NP type and applied dose. The applications of SiO2-NPs and MnO2-NPs with an appropriate dose hold great promise for mitigating the salt-induced photosynthetic dysfunction via regulation of related key genes, and ultimately promoting plant growth and ameliorating the salt-tolerance.

Green synthesis of selenium nanoparticles from Cassia javanica flowers extract and their medical and agricultural applications

Nanostructured materials are advantageous within numerous fields of medicine owing to their intriguing qualities, which include their size, reactive surface, bioactivity, potential for modification, and optical characteristics. Cassia javanica flower extract was used as a chelating agent in an environmentally friendly process to create SeNPs FTIR, XRD, and TEM, SAED were utilized to analyze and characterize the synthesized. The findings showed that the MIC of Se NPs against B. subtilis and S. aureus was 500 µg/ml. Conversely, the MIC for P. aeruginosa, E. coli, and C. albicans were 125, 250, and 62.5 µg/ml, respectively. Hence, SeNPs considerably reduced the activity; the inhibition peaked at 77.6% at 250 µg/ml to reach 49.04% at 7.8 µg/ml. Which showed the greatest suppression of MRSA biofilm formation without affecting bacterial growth. SeNPs showed an intriguing antioxidant capacity, achieving an IC50 of 53.34 µg/ml. This study looked how soaking seeds before sowing them with Se NPs at 50, 100, and 200 ppm affected the plants' development in different parameters, as well as their yield of Vicia faba L. The growth conditions were effectively increased by soaking application of various quantities of Se NPs. The highest values of dry weight/pod (g), number of seeds/plant, weight of 100 seeds (g), and number of pods/plant were caused by high concentrations of Se NPs, by 28.43, 89.60, 18.20, and 94.11%, respectively.

Harnessing the potential of copper-based nanoparticles in mitigating abiotic and biotic stresses in crops

The demand for crops production continues to intensify with the rapid increase in population. Agricultural crops continue to encounter abiotic and biotic stresses, which can substantially hamper their productivity. Numerous strategies have been focused to tackle the abiotic and biotic stress factors in various plants. Nanotechnology has displayed great potential to minimize the phytotoxic impacts of these environmental constraints. Copper (Cu)-based nanoparticles (NPs) have displayed beneficial effects on plant growth and stress tolerance. Cu-based NPs alone or in combination with plant growth hormones or microorganisms have been documented to induce plant tolerance and mitigate abiotic or biotic stresses in different plants. In this review, we have comprehensively discussed the uptake and translocation of Cu-based NPs in plants, and beneficial roles in improving the plant growth and development at various growth stages. Moreover, we have discussed how Cu-based NPs mechanistically modulate the physiological, biochemical, metabolic, cellular, and metabolic functions to enhance plant tolerance against both biotic (viruses, bacterial and fungal diseases, etc.) and abiotic stresses (heavy metals or metalloids, salt, and drought stress, etc.). We elucidated recent advancements, knowledge gaps, and recommendations for future research. This review would help plant and soil scientists to adapt Cu-based novel strategies such as nanofertilizers and nanopesticides to detoxify the abiotic or biotic stresses. These outcomes may contribute to the promotion of healthy food production and food security, thus providing new avenues for sustainable agriculture production.

Effects of LED polarized and vortex light on growth and photosynthetic characteristics of pepper (Capsicum annuum L.)

Most studies currently focus on traditional illuminant regulating plant growth, while less attention has been given to the LED internal luminescence. This study examined how polarized and vortex light affect the growth and photosynthetic traits of pepper plants, with LED light used as the control. The findings indicated that circular polarized light significantly increased the aboveground biomass of pepper. Additionally, both polarized and vortex light treatment significantly influenced the root development of pepper. In comparison to the control group, the chlorophyll content was highest under circular polarized light, while the Pn, Sc, Tr, and Ci values were highest under linear polarized light, and the enzyme activity of Rubisco was increased. Circular polarized light notably increased the activities of POD, CAT, and SOD, the activity of SOD reached its peak under the left vortex light. Moreover, the content of MDA was observed to be the lowest under linear and right vortex light treatments. The expressions of key genes for chlorophyll synthesis (CaHEMA1 and CaCAO) and antioxidant enzyme synthesis (CaPOD, CaSOD, and CaMDHAR) were significantly altered under varying polarized light conditions, The latter genes, which play crucial roles in antioxidant enzyme activity, also showed significant variations in response to different polarized light treatments. In conclusion, polarized light significantly impacts the growth of pepper and is anticipated to be utilized for plant growth, setting the stage for future research in this area.

Examining the Correlation between the Inorganic Nano-Fertilizer Physical Properties and Their Impact on Crop Performance and Nutrient Uptake Efficiency

The physical properties of nano-fertilizers (NFs) are important in determining their performance, efficacy, and environmental interactions. Nano-fertilizers, due to their small size and high surface area-to-volume ratio, enhance plant metabolic reactions, resulting in higher crop yields. The properties of nano-fertilizers depend on the synthesis methods used. The nanoparticle's nutrient use efficiency (NUE) varies among plant species. This review aims to analyze the relationship between the physical properties of NF and their influence on crop performance and nutrient uptake efficiency. The review focuses on the physical properties of NFs, specifically their size, shape, crystallinity, and agglomeration. This review found that smaller particle-sized nanoparticles exhibit higher nutrient use efficiency than larger particles. Nano-fertilizer-coated additives gradually release nutrients, reducing the need for frequent application and addressing limitations associated with chemical fertilizer utilization. The shapes of nano-fertilizers have varying effects on the overall performance of plants. The crystalline structure of nanoparticles promotes a slow release of nutrients. Amorphous nano-fertilizers improve the NUE and, ultimately, crop yield. Agglomeration results in nanoparticles losing their nanoscale size, accumulating on the outer surface, and becoming unavailable to plants. Understanding the physical properties of nano-fertilizers is crucial for optimizing their performance in agricultural applications.

Zinc-loaded mesoporous silica nanoparticles mitigate salinity stress in wheat seedlings through silica-zinc uptake, osmotic balance, and ROS detoxification

Abiotic stresses like salinity and micronutrient deficiency majorly affect wheat productivity. Applying mesoporous silica nanoparticles (MSiNPs) as a smart micronutrient delivery system can facilitate better stress management and nutrient delivery. In this purview, we investigated the potential of MSiNPs and Zn-loaded MSiNPs (Zn-MSiNPs) on the growth and physiology of wheat seedlings exposed to salinity stress (200 mM NaCl). Initially, the FESEM, DLS, and BET analysis portrayed nanoparticles' spherical shape, nano-size, and negatively charged mesoporous surface. A sustained release of Zn+2 from Zn-MSiNPs at 30 °C, diffused light, and pH 7 was perceived with a 96.57% release after 10 days. Further, the mitigation of NaCl stress in the wheat seedlings was evaluated with two different concentrations, each of MSiNPs and Zn-MSiNPs (1 g/L and 5 g/L), respectively. A meticulous improvement in the germination and growth of wheat seedlings was observed when treated with both MSiNPs and Zn-MSiNPs. A considerable increase in chlorophyll, total protein, and sugar content was in consort with a substantial decline in MDA, electrolyte leakage, and ROS accumulation, showcasing the nanomaterials' palliating effects. Most importantly, the K+/Na+ ratio in shoots increased significantly by 3.43 and 4.37 folds after being treated with 5 g/L Zn-MSiNPs, compared to their respective control sets (0 and 200 mM NaCl). Therefore, it can be concluded that the Zn-MSiNPs can effectively restrain the effects of salinity stress on wheat seedlings.

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.

Polyvinylpyrrolidone-coated copper nanoparticles dose-dependently conferred tolerance to wheat under salinity and/or drought stress by improving photochemical activity and antioxidant system

Copper (Cu) is one of the essential micronutrients for plants and has been used extensively in agricultural applications from the past to the present. However, excess copper causes toxic effects such as inhibiting photosynthesis, and disrupting biochemical processes in plants. Nanotechnology applications have offered a critical method for minimizing adverse effects and improving the effectiveness of copper nanoparticles. For this purpose, this study investigated the physiological and biochemical effects of polyvinylpyrrolidone (PVP)-coated Cu nanoparticles (PVP-Cu NP, N1, 100 mg L-1; N2, 400 mg L-1) in Triticum aestivum under alone or combined with salt (S, 150 mM NaCl) and/or drought (D, %10 PEG-6000) stress. Salinity and water deprivation caused 51% and 22% growth retardation in wheat seedlings. The combined stress condition (S + D) resulted in an approximately 3-fold reduction in the osmotic potential of the leaves. PVP-Cu NP treatments to plants under stress, especially N1 dose, were effective in restoring growth rate and regulating water relations. All stress treatments limited gas exchange in stomata and suppressed the maximal quantum yield of PSII (Fv/Fm). More than 50% improvement was observed in stomatal permeability and carbon assimilation rate under S + N1 and S + N2 applications. Examination of OJIP transient parameters revealed that N1 treatments protected photochemical reactions by reducing the dissipated energy flux (DIo/RC) in drought and S + D conditions. Exposure to S and/or D stress caused high hydrogen peroxide (H2O2) accumulation and lipid peroxidation in wheat leaves. The results indicated that S + N1 and S + N2 treatments reduced oxidative damage by stimulating the activities of antioxidant enzymes superoxide dismutase (SOD), peroxidase (POX), and ascorbate peroxidase (APX). Although similar effects were observed at D and S + D conditions with 100 mg L-1 PVP-Cu NP treatments (N1), the curative effect of the N2 dose was not observed. In D + N1 and S + D + N1 groups, AsA regeneration and GSH redox status were maintained by triggering APX, GR, and other enzyme activities belonging to the AsA-GSH cycle. In these groups, N2 treatment did not contribute to the availability of enzymatic and non-enzymatic antioxidants. As a result, this study revealed that N1 dose PVP-Cu NP application was successful in providing stress tolerance and limiting copper-induced adverse effects under all stress conditions.

Ascorbic acid and selenium nanoparticles synergistically interplay in chromium stress mitigation in rice seedlings by regulating oxidative stress indicators and antioxidant defense mechanism

Ascorbic acid (AsA) and selenium nanoparticles (SeNPs) were versatile plant growth regulators, playing multiple roles in promoting plant growth under heavy metal stresses. This study aimed to evaluate the beneficial role of individual and combined effects of AsA and SeNPs on morpho-physio-biochemical traits of rice with or without chromium (Cr) amendment. The results indicated that Cr negatively affected plant biomass, gas exchange parameters, total soluble sugar, proline, relative water contents, and antioxidant-related gene expression via increasing reactive oxygen species (MDA, H2O2, O2•-) formation, resulting in plant growth reduction. The application of AsA and SeNPs, individually or in combination, decreased the uptake and translocation of Cr in rice seedlings, increased seedlings with tolerance to Cr toxicity, and significantly improved the rice seedling growth. Most notably, AsA + SeNP treatment strengthened the antioxidative defense system through ROS quenching and Cr detoxification. The results collectively suggested that the application of AsA and SeNPs alone or in combination had the potential to alleviate Cr toxicity in rice and possibly other crop species.

Biochemical changes and enhanced accumulation of phenolic compounds in cell culture of Perilla frutescens (L.) by nano-chemical elicitation

Perilla frutescens (L.) Britt is a renowned medicinal plant with pharmaceutically valuable phenolic acids and flavonoids. The present study was aimed to study the eliciting effect of silver and copper nanoparticles (AgNPs and CuNPs, 50 and 100 mg/L), and methyl jasmonate (MeJa, 50 and 100 μM) on the biochemical traits, the accumulation of phenolic compounds and antioxidative capacity of P. frutescens cell suspension culture. Suspension cells were obtained from friable calli derived from nodal explants in Murashige and Skoog (MS) liquid medium containing 1 mg/L 2,4-D and 1 mg/L BAP. The 21 days old cell suspension culture established from nodal explant derived callus supplemented with 100 mg/L MeJa resulted in the highest activity of catalase and guaiacol peroxidase enzymes, and CuNPs 100 mg/L treated cells indicated the maximum content of total phenol, total anthocyanin, superoxide dismutase, malondialdehyde, and H2O2. Also, the highest content of ferulic acid (1.41 ± 0.03, mg/g DW), rosmarinic acid (19.29 ± 0.12, mg/g DW), and phenylalanine ammonia-lyase (16.81 ± 0.18, U/mg protein) were observed with 100 mg/L CuNPs, exhibiting a total increase of 1.58-fold, 2.12-fold, and 1.51-fold, respectively, higher than untreated cells. On the other hand, AgNPs 100 mg/L treated cells indicated the most amounts of caffeic acid (0.57 ± 0.03, mg/g DW) and rutin (1.13 ± 0.07, mg/g DW), as well as the highest scavenging potential of free radicals. Overall, the results of the present study can be applied for the large-scale production of valuable phenolic acids and flavonoids from P. frutescens through CuNPs and AgNPs 100 mg/L elicited cell suspension cultures.

Salinity stress and nanoparticles: Insights into antioxidative enzymatic resistance, signaling, and defense mechanisms

Salinized land is slowly spreading across the world. Reduced crop yields and quality due to salt stress threaten the ability to feed a growing population. We discussed the mechanisms behind nano-enabled antioxidant enzyme-mediated plant tolerance, such as maintaining reactive oxygen species (ROS) homeostasis, enhancing the capacity of plants to retain K+ and eliminate Na+, increasing the production of nitric oxide, involving signaling pathways, and lowering lipoxygenase activities to lessen oxidative damage to membranes. Frequently used techniques were highlighted like protecting cells from oxidative stress and keeping balance in ionic state. Salt tolerance in plants enabled by nanotechnology is also discussed, along with the potential role of physiobiochemical and molecular mechanisms. As a whole, the goal of this review is meant to aid researchers in fields as diverse as plant science and nanoscience in better-comprehending potential with novel solutions to addressing salinity issues for sustainable agriculture.

Noteworthy biocompatibility of effective microorganisms (EM) like microbial beneficial culture formulation with metal and metal oxide nanoparticles

The present study evaluates the biocompatibility of silver and zinc oxide nanoparticles with various effective microorganisms (EM), like beneficial microbial formulations. The respective nanoparticle was synthesised by chemical reduction of metal precursor with reducer via simple route green technology principles. The synthesised nanoparticles were characterised by UV visible spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) studies, revealing highly stable, nanoscale particles with marked crystallinity. EM-like beneficial cultures composed of viable cells of Lactobacillus lactis, Streptomyces sp, Candida lipolytica, and Aspergillus oryzae were formulated with rice bran, sugarcane syrup, and groundnut cake. The respective formulation was inoculated into the nanoparticles amalgamated pots raised with green gram seedlings. Biocompatibility was determined by measuring plant growth parameters of a green gram at pre-determined periods associated with enzymatic antioxidants like catalase (CAT), superoxide dismutase (SOD), and glutathione S transferase (GST) levels. Most significantly, the expression level of these enzymatic antioxidants level was also investigated by quantitative real-time polymerase chain reaction (qRT-PCR). The impact of the soil conditioning effect on soil nutrients like nitrogen, phosphorous, potassium, organic carbon, soil enzymes glucosidases, and β-xylosidases activity was also studied. Among the formulation, rice bran-groundnut cake-sugar syrup formulation recorded the best biocompatibility. This formulation showed high growth promotion, soil conditioning effect and no impact on the oxidative stress enzymes genes that revealed the best compatibility of nanoparticles. This study concluded that biocompatible, eco-friendly formulations of microbial inoculants could be used for the desirable agro active properties that show extreme tolerance or biocompatibility to the nanoparticles. This present study also suggests the utilisation of the above said beneficial microbial formulation and metal-based nanoparticles with desirable agro active properties in a synergistic manner due to their high tolerance or compatibility towards the metal or metal oxide nanoparticles.

ZnO nanoparticles as potential fertilizer and biostimulant for lettuce

Zn is an indispensable nutrient for crops that usually presents low bioavailability. Different techniques have been proposed to improve the bioavailability of Zn, including the use of nanofertilizers. The objective of the study was to evaluate the applications of drench (D) and foliar (F) ZnO nanoparticles (NZnO) compared to those of ionic Zn²⁺ (ZnSO₄) in lettuce. The plants cv. Great Lakes 407 was produced in pots of 4 L with perlite-peat moss (1:1) under greenhouse conditions. The treatments consisted of NZnO applications that replaced the total Zn provided with a Steiner solution, as follows: Zn²⁺ (100%D) (control); Zn²⁺ (50%D+50%F); NZnO (100%D); NZnO (50%D+50%F); NZnO (75%D); NZnO (50%D); NZnO (75%F) and NZnO (50%F). Four applications of Zn were made with a frequency of 15 days. 75 days after transplant (DAP), the fresh and dry biomass, chlorophyll a, b, and β-carotene, phenolics, flavonoids, antioxidant capacity, vitamin C, glutathione, H₂O₂, total protein, and enzymatic activity of PAL, CAT, APX, and GPX were evaluated. The mineral concentrations (N, P, K, Ca, Mg, S, Cu, Fe, Mn, Mo, Zn, Ni, and Si) in the leaves and roots of plants were also determined. The results showed that, compared to Zn²⁺, NZnO promoted increases in biomass (14-52%), chlorophylls (32-69%), and antioxidant compounds such as phenolics, flavonoids, and vitamin C. The activity of enzymes like CAT and APX, as well as the foliar concentration of Ca, Mg, S, Fe, Mn, Zn, and Si increased with NZnO. A better response was found in the plants for most variables with foliar applications of NZnO equivalent to 50-75% of the total Zn²⁺ applied conventionally. These results demonstrate that total replacement of Zn²⁺ with NZnO is possible, promoting fertilizer efficiency and the nutraceutical quality of lettuce.

Fighting Obesity-Related Micronutrient Deficiencies through Biofortification of Agri-Food Crops with Sustainable Fertilization Practices

Obesity is a critical medical condition worldwide that is increasingly involved with nutritional derangements associated with micronutrient deficiencies, including iron, zinc, calcium, magnesium, selenium, and vitamins A, C, D, and E. Nutritional deficiencies in obesity are mainly caused by poor-quality diets, higher nutrient requirements, alterations in micronutrient metabolism, and invasive obesity treatments. The current conventional agricultural system is designed for intensive food production, focusing on food quantity rather than food quality, consuming excessive agricultural inputs, and producing nutrient-deficient foods, thus generating severe health and environmental problems; agricultural food products may worsen obesity-related malnutrition. Therefore, modern agriculture is adopting new biofortification technologies to combat micronutrient deficiencies and improve agricultural productivity and sustainability. Biofertilization and nanofertilization practices are increasingly used due to their efficiency, safety, and reduced environmental impact. Biofertilizers are preparations of PGP-microorganisms that promote plant growth by influencing plant metabolism and improving the nutrient uptake, and nanofertilizers consist of synthesized nanoparticles with unique physicochemical properties that are capable of increasing plant nutrition and enriching agricultural products. This review presents the current micronutrient deficiencies associated with obesity, the modern unsustainable agri-food system contributing to obesity progression, and the development of bio- and nanofertilizers capable of biofortifying agri-food crops with micronutrients commonly deficient in patients with obesity.

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.

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.

Mitigation of the salinity stress in rapeseed (Brassica napus L.) productivity by exogenous applications of bio-selenium nanoparticles during the early seedling stage

In recent years, much attention has been directed toward using nanoparticles (NPs) as one of the most effective strategies to improve plant growth, especially under salt stress conditions. Further research has been conducted to develop NPs using various chemical ways; accordingly, knowledge about the beneficial effect of bioSeNPs in rapeseed is obscure. Selenium (Se) is a vital micronutrient with a series of physiological and antioxidative properties. Seed priming is emerging as a low-cost, efficient, and environment-friendly seed treatment in nanotechnology. The current study was carried out to examine the promising effects of nanopriming via bioSeNPs on the expression level of aquaporin genes, seed microstructure, seed germination, growth traits, physiochemical attributes, and minerals uptake of two rapeseed cultivars under salinity stress conditions. Our investigation monitored the positive effects of bioSeNPs on the expression level of aquaporin genes (BnPIP1-1 and BnPIP2-1) and water uptake during the seed imbibition (4 and 8 h of priming), which indicated higher imbibition potential and germination promotion with bioSeNPs application (most effective at 150 μmol/L). The total performance index was significantly enhanced with nano-treatments in rapeseed seedlings. Collectively, nano-application improved seed microstructure, seed germination, and photosynthetic efficiency directly correlated with higher seedlings biomass, especially with a higher concentration of bioSeNPs. The enhancement in α-amylase and free amino acid contents in nanoprimed seeds resulted in rapid seed germination. Moreover, bioSeNPs increased the osmotic adjustment and enhanced the efficiency of the plant's defense system by improving the activity of enzymatic and non-enzymatic antioxidants, thus enhancing ROS scavenging under salt stress. The obtained results may indicate the strengthening of seed vigor, improving seedling growth and physiochemical attributes via bioSeNPs. Our findings displayed that bioSeNPs modulated the Na⁺ and K⁺ uptake, which improved the rapeseed growth and showed a close relationship with the low contents of toxic Na⁺ ion; thus, it prevented oxidative damage due to salt stress. This comprehensive data can add more knowledge to understand the mechanisms behind plant-bioSeNPs interaction and provide physiological evidence for the beneficial roles of nanopriming using bioSeNPs on rapeseed germination and seedling development under salinity stress conditions. Such studies can be used to develop simple prepackaged nano primer products, which can be used before sowing to boost seed germination and crop productivity under stress conditions.

A Comprehensive Overview of Nanotechnology in Sustainable Agriculture

Plant nutrition is crucial in crop productivity and providing food security to the ever-expanding population. Application of chemical/biological fertilizers and pesticides are the mainstays for any agricultural economy. However, there are unintended consequences of using chemical fertilizers and pesticides. The environment and ecological balance are adversely affected by their usage. Biofertilizers and biopesticides counter some undesired environmental effects of chemical fertilizers/pesticides; inspite of some drawbacks associated with their use. The recent developments in nanotechnology offer promise towards sustainable agriculture. Sustainable agriculture involves addressing the concerns about agriculture as well as of the environment. This review briefs about important nanomaterials used in agriculture as nanofertilizers, nanopesticides, and a combination called nanobiofertilizers. Both nanofertilizers and nanopesticides enable slow and sustained release besides their eco-friendly environmental consequences. They can be tailored to specific needs to crop. Nanofertilizers also offer greater stress tolerance and, therefore, of considerable value in the era of climate change. Furthermore, nanofertilizers/nanopesticides are applied in minute amounts, reducing transportation costs associated and thus positively affecting the economy. Their uses extend beyond such as if nanoparticles (NPs) are used at high concentrations; they affect plant pathogens adversely. Polymer-based biodegradable nanofertilizers and nanopesticides offer various benefits. There is also a dark side to the use of nanomaterials in agriculture. Nanotechnology often involves the use of metal/metal oxide nanoparticles, which might get access to human bodies leading to their accumulation through bio-magnification. Although their effects on human health are not known, NPs may reach toxic concentrations in soil and runoff into rivers, and other water bodies with their removal to become a huge economic burden. Nevertheless, a risk-benefit analysis of nanoformulations must be ensured before their application in sustainable agriculture.

Foliar Application of Nano-Silicon Improves the Physiological and Biochemical Characteristics of ‘Kalamata’ Olive Subjected to Deficit Irrigation in a Semi-Arid Climate

In Egypt’s arid and semi-arid lands where the main olive production zone is located, evapotranspiration is higher than rainfall during winter. Limited research has used nanomaterials, especially nano-silicon (nSi) to improve the growth, development, and productivity of drought-stressed fruit trees, amid the global water scarcity problem. To assess the role of nSi on drought-sensitive ‘Kalamata’ olive tree growth, and biochemical and physiological changes under drought conditions, a split-plot experiment was conducted in a randomized complete block design. The trees were foliar sprayed with nSi in the field using nine treatments (three replicates each) of 0, 150, and 200 mg·L−1 under different irrigation regimes (100, 90, and 80% irrigation water requirements ‘IWR’) during the 2020 and 2021 seasons. Drought negatively affected the trees, but both concentrations of nSi alleviated drought effects at reduced irrigation levels, compared to the non-stressed trees. Foliar spray of both concentrations of nSi at a moderate level (90% IWR) of drought resulted in improved yield and fruit weight and reduced fruit drop percentage, compared to 80% IWR. In addition, there were reduced levels of osmoprotectants such as proline, soluble sugars, and abscisic acid (ABA) with less membrane damage expressed as reduced levels of malondialdehyde (MDA), H2O2 and electrolyte leakage at 90% compared to 80% IWR. These results suggest that ‘Kalamata’ olive trees were severely stressed at 80% compared to 90% IWR, which was not surprising as it is classified as drought sensitive. Overall, the application of 200 mg·L−1 nSi was beneficial for the improvement of the mechanical resistance, growth, and productivity of moderately-stressed (90% IWR) ‘Kalamata’ olive trees under the Egyptian semi-arid conditions.

Rhizophagus irregularis and Nitrogen Fixing Azotobacter with a Reduced Rate of Chemical Fertilizer Application Enhances Pepper Growth along with Fruits Biochemical and Mineral Composition

Bell pepper is an important vegetable crop containing lots of bioactive compounds. The present study was designed to improve the productivity and quality of bell pepper with the application of arbuscular mycorrhizal fungi (Rhizophagus irregularis) and plant growth-promoting bacteria (Azotobacter chroococcum) in a combination of chemical fertilizer. Five treatments consisted of 75% chemical fertilizer (T1), 100% chemical fertilizer (T2), 75% chemical fertilizer + R. irregularis (T3), 75% chemical fertilizer + A. chroococcum (T4) and 75% chemical fertilizer + R. irregularis + A. chroococcum (T5). Out of 18 morphological parameters, 11 morphometric fruit parameters were recorded in detail by a tomato analyzer. The morphological and biochemical (TSS, ascorbic acid and capsaicin content) attributes of bell pepper were recorded higher in the case of a mixed consortium of chemical fertilizers having R. irregularis and A. chroococcum. Similarly, the amount of mineral content recorded was highest after 75% chemical fertilizer + R. irregularis + A. chroococcum, followed by the treatment with only 100% chemical fertilizer. The root mycorrhization (%) and the number of spores were observed highest in 75% chemical fertilizer + R. irregularis + A. chroococcum, and there was no mycorrhization and spore formation in 75% CF, 100% CF and 75% CF+AC. The treatment involving 75% chemical fertilizer + R. irregularis + A. chroococcum proved better for pepper’s growth, yield and yield-related traits.

Comparative efficacy of bio-selenium nanoparticles and sodium selenite on morpho-physiochemical attributes under normal and salt stress conditions, besides selenium detoxification pathways in Brassica napus L

Selenium nanoparticles (SeNPs) have attracted considerable attention globally due to their significant potential for alleviating abiotic stresses in plants. Accordingly, further research has been conducted to develop nanoparticles using chemical ways. However, our knowledge about the potential benefit or phytotoxicity of bioSeNPs in rapeseed is still unclear. Herein, we investigated the effect of bioSeNPs on growth and physiochemical attributes, and selenium detoxification pathways compared to sodium selenite (Se (IV)) during the early seedling stage under normal and salt stress conditions. Our findings showed that the range between optimal and toxic levels of bioSeNPs was wider than Se (IV), which increased the plant’s ability to reduce salinity-induced oxidative stress. BioSeNPs improved the phenotypic characteristics of rapeseed seedlings without the sign of toxicity, markedly elevated germination, growth, photosynthetic efficiency and osmolyte accumulation versus Se (IV) under normal and salt stress conditions. In addition to modulation of Na⁺ and K⁺ uptake, bioSeNPs minimized the ROS level and MDA content by activating the antioxidant enzymes engaged in ROS detoxification by regulating these enzyme-related genes expression patterns. Importantly, the main effect of bioSeNPs and Se (IV) on plant growth appeared to be correlated with the change in the expression levels of Se-related genes. Our qRT-PCR results revealed that the genes involved in Se detoxification in root tissue were upregulated upon Se (IV) treated seedlings compared to NPs, indicating that bioSeNPs have a slightly toxic effect under higher concentrations. Furthermore, bioSeNPs might improve lateral root production by increasing the expression level of LBD16. Taken together, transamination and selenation were more functional methods of Se detoxification and proposed different degradation pathways that synthesized malformed or deformed selenoproteins, which provided essential mechanisms to increase Se tolerance at higher concentrations in rapeseed seedlings. Current findings could add more knowledge regarding the mechanisms underlying bioSeNPs induced plant growth.

Can Nanofertilizers Mitigate Multiple Environmental Stresses for Higher Crop Productivity?

The global food production for the worldwide population mainly depends on the huge contributions of the agricultural sector. The cultivated crops of foods need various elements or nutrients to complete their growth, and these are indirectly consumed by humans. During this production, several environmental constraints or stresses may cause losses in the global agricultural production. These obstacles may include abiotic and biotic stresses, which have already been studied in both individual and combined cases. However, there are very few studies on multiple stresses. On the basis of the myriad benefits of nanotechnology in agriculture, nanofertilizers (or nanonutrients) have become promising tools for agricultural sustainability. Nanofertilizers are also the proper solution to overcoming the environmental and health problems that can result from conventional fertilizers. The role of nanofertilizers has increased, especially under different environmental stresses, which can include individual, combined, and multiple stresses. The stresses are most commonly the result of nature; however, studies are still needed on the different stress levels. Nanofertilizers can play a crucial role in supporting cultivated plants under stress and in improving the plant yield, both quantitatively and qualitatively. Similar to other biological issues, many open-ended questions still require further investigation: Is the right time and era for nanofertilizers in agriculture? Will the nanofertilizers be the dominant source of nutrients in modern agriculture? Are nanofertilizers, and particularly biological synthesized ones, the magic solution for sustainable agriculture? What are the expected damages of multiple stresses on plants?

Nanoforms of essential metals: from hormetic phytoeffects to agricultural potential

Vital plant functions require at least six metals (copper, iron, molybdenum, manganese, zinc, and nickel), which function as enzyme cofactors or inducers. In recent decades, rapidly evolving nanotechnology has created nanoforms of essential metals and their compounds (e.g. nZnO, nFe2O3) with a number of favourable properties over the bulk materials. The effects of nanometals on plants are concentration-dependent (hormesis) but also depend on the properties of the nanometals, the plant species, and the treatment conditions. Here, we review studies examining plant responses to essential nanometal treatments using a (multi)omics approach and emphasize the importance of gaining a holistic view of the diverse effects. Furthermore, we discuss the beneficial effects of essential nanometals on plants, which provide the basis for their application in crop production as, for example, nanopriming or nanostimulator agents, or nanofertilizers. As lower environmental impact and increased yield can be achieved by the application of essential nanometals, they support sustainable agriculture. Recent studies have actively examined the utilization of green-synthesized metal nanoparticles, which perfectly fit into the environmentally friendly trend of future agriculture. Further knowledge is required before essential nanometals can be safely applied in agriculture, but it is a promising direction that is timely to investigate.

Interactions of nanoparticles and salinity stress at physiological, biochemical and molecular levels in plants: A review

Salinity stress is one of the most destructive non-biological stresses in plants that has adversely affected many agricultural lands in the world. Salinity stress causes many morphological, physiological, epigenetic and genetic changes in plants by increasing sodium and chlorine ions in the plant cells. The plants can alleviate this disorder to some extent through various mechanisms and return the cell to its original state, but if the salt dose is high, the plants may not be able to provide a proper response and can die due to salt stress. Nowadays, scientists have offered many solutions to this problem. Nanotechnology is one of the most emerging and efficient technologies that has been entered in this field and has recorded very brilliant results. Although some studies have confirmed the positive effects of nontechnology on plants under salinity stress, there is no the complete understanding of the relationship and interaction of nanoparticles and intracellular mechanisms in the plants. In the review paper, we have tried to reach a conclusion from the latest articles that how NPs could help salt-stressed plants to recover their cells under salt stress so that we can take a step towards clearing the existing ambiguities for researchers in this field.

Synthesis and Characterization of a Mixed Nanofertilizer Influencing the Nutrient Use Efficiency, Productivity, and Nutritive Value of Tomato Fruits

Due to the higher potential for enhancing nutrient use efficiency, nanofertilizer (NF) is crucial in sustainable crop production. Thus, foliar-applied mixed nanofertilizer (MNFf) and commercial fertilizer (CF) into the soil (CFs) were claimed together ([MNFf + CFs]) and comparative nutrient use efficiency (NUE), productivity, and nutritional properties of tomato fruits were investigated. The mixed nanofertilizer (MNF) was prepared in our laboratory and characterized using scanning electron microscopy, X-ray diffraction, and Fourier transform infrared. To avoid the interference of other factors, all the treatments were divided into three groups: (i) blank treatment (no fertilizer), (ii) CF treatment, and (iii) combined [MNFf + CFs] treatment. The vegetative growth and qualitative and quantitative attributes of tomatoes were recorded, and the NUE, total production, and benefit-cost ratio (BCR) were also calculated. In addition, comparative nutritional properties for all treatments were analyzed. The plant's height, stem diameter, root length, photosynthetic pigments, leaf minerals, and qualitative traits of tomato fruits were significantly (p < 0.05) increased by [MNFf + CFs] treatment compared to CFs. The protein, fiber, Fe, Zn, and K contents were significantly (p < 0.05) increased by 23.80, 38.10, 44.23, 60.01, and 2.39%, respectively, with the [MNFf + CFs] treatment as compared to CFs, while the ash and protein contents were both lower than the untreated tomato. Moreover, [MNFf + CFs] treatment has significantly (p < 0.05) increased the antioxidant properties. The NUE, total production, and BCR were also increased by 26.08, 26.04, and 25.38%, respectively, with the same treatment. Thus, [MNFf + CFs] treatment could be a potential alternative for reducing the excess use of CF.

Nano-biofortification of different crops to immune against COVID-19: A review

Human health and its improvement are the main target of several studies related to medical, agricultural and industrial sciences. The human health is the primary conclusion of many studies. The improving of human health may include supplying the people with enough and safe nutrients against malnutrition to fight against multiple diseases like COVID-19. Biofortification is a process by which the edible plants can be enriched with essential nutrients for human health against malnutrition. After the great success of biofortification approach in the human struggle against malnutrition, a new biotechnological tool in enriching the crops with essential nutrients in the form of nanoparticles to supplement human diet with balanced diet is called nano-biofortification. Nano biofortification can be achieved by applying the nano particles of essential nutrients (e.g., Cu, Fe, Se and Zn) foliar or their nano-fertilizers in soils or waters. Not all essential nutrients for human nutrition can be biofortified in the nano-form using all edible plants but there are several obstacles prevent this approach. These stumbling blocks are increased due to COVID-19 and its problems including the global trade, global breakdown between countries, and global crisis of food production. The main target of this review was to evaluate the nano-biofortification process and its using against malnutrition as a new approach in the era of COVID-19. This review also opens many questions, which are needed to be answered like is nano-biofortification a promising solution against malnutrition? Is COVID-19 will increase the global crisis of malnutrition? What is the best method of applied nano-nutrients to achieve nano-biofortification? What are the challenges of nano-biofortification during and post of the COVID-19?

Bell Peppers (Capsicum annum L.) Losses and Wastes: Source for Food and Pharmaceutical Applications

Currently, the high added-value compounds contained in plant by-products and wastes offer a wide spectrum of opportunities for their reuse and valorization, contributing to the circular economy. The bell pepper (Capsicum annum L.) is an exotic vegetable with high nutritional value that, after processing, leaves wastes (peel, seeds, and leaves) that represent desirable raw material for obtaining phytochemical compounds. This review summarizes and discusses the relevant information on the phytochemical profile of bell peppers and their related biological properties as an alternative to revalorize losses and wastes from bell peppers for their application in the food and pharmaceutical industries. Bell pepper fruits, seeds, and leaves contain bioactive compounds (phenols, flavonoids, carotenoids, tocopherol, and pectic polysaccharides) that exhibit antioxidant, antibacterial, antifungal, immunosuppressive and immunostimulant properties, and antidiabetic, antitumoral and neuroprotective activities, and have a potential use as functional food additives. In this context, the revalorization of food waste is positioned as a technological and innovative research area with beneficial effects for the population, the economy, and the environment. Further studies are required to guarantee the safety use of these compounds and to understand their mechanisms of action.

Synthesis of Copper Nanoparticles Stabilized with Organic Ligands and Their Antimicrobial Properties

In this work, we report the synthesis of copper nanoparticles (Cu NPs), employing the chemical reduction method in an aqueous medium. We used copper sulfate pentahydrate (CuSO₄·5H₂O) as a metallic precursor; polyethylenimine (PEI), allylamine (AAM), and 4-aminobutyric acid (AABT) as stabilizing agents; and hydrated hydrazine as a reducing agent. The characterization of the obtained nanoparticles consisted of X-ray, TEM, FTIR, and TGA analyses. Through these techniques, it was possible to detect the presence of the used stabilizing agents on the surface of the NPs. Finally, a zeta potential analysis was performed to differentiate the stability of the nanoparticles with a different type of stabilizing agent, from which it was determined that the most stable nanoparticles were the Cu NPs synthesized in the presence of the PEI/AAM mixture. The antimicrobial activity of Cu/PEI/AABT toward P. aeruginosa and S. aureus bacteria was high, inhibiting both bacteria with low contact times and copper concentrations of 50–200 ppm. The synthesis method allowed us to obtain Cu NPs free of oxides, stable to oxidation, and with high yields. The newly functionalized Cu NPs are potential candidates for antimicrobial applications.

Antimicrobial Property of Polypropylene Composites and Functionalized Copper Nanoparticles

Copper nanoparticles (CuNPs) functionalized with polyethyleneimine (PEI) and 4-aminobutyric acid (GABA) were used to obtain composites with isotactic polypropylene (iPP). The iPP/CuNPs composites were prepared at copper concentrations of 0.25-5.0 wt % by melt mixing, no evidence of oxidation of the CuNP was observed. Furthermore, the release of copper ions from iPP/CuNPs composites in an aqueous medium was studied. The release of cupric ions was higher in the composites with 2.5 and 5.0 wt %. These composites showed excellent antibacterial activity (AA) toward Pseudomona aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). The incorporation of CuNP into the iPP polymeric matrix slightly decreased the thermal stability of the composite material but improved the crystallinity and the storage modulus. This evidence suggests that CuNPs could work as nucleating agents in the iPP crystallization process. The iPP/CuNPs composites presented better AA properties compared to similar composites reported previously. This behavior indicates that the new materials have great potential to be used in various applications that can be explored in the future.