Cu Nanoparticles in Hydrogels of Chitosan-PVA Affects the Characteristics of Post-Harvest and Bioactive Compounds of Jalapeño Pepper

Current and potential future biological uses of Saussurea costus (Falc.) Lipsch: A comprehensive review

Background

Saussurea costus (S. costus) is a critically endangered medicinal plant that has been extensively studied for its chemical composition, significance, and therapeutic potential as traditional phytomedicine. This comprehensive review aims to provide a thorough understanding of S. costus, including its biological activities, chemical makeup, and potential therapeutic uses in biotechnology.

Objectives

This study investigated the pharmacological properties of S. costus, including its antimicrobial, antioxidant, and antifungal properties, and its usefulness in treating conditions such as thyroid disorders and liver injury. This study also aimed to assess and improve the techniques used to extract bioactive compounds and to develop effective methods for harvesting these compounds from medicinal plants.

Methods

This review analyzed the available literature on the phytochemical makeup and bioactivity of S. costus extract using techniques such as molecular docking against SARS-CoV-2 protease, green extraction methods, and phytochemical analysis.

Results

This review revealed that S. costus possesses various pharmacological properties, including antimicrobial, antiviral, anti-inflammatory, and anticancer activities. It is effective in combating fungal infections, reducing inflammation, treating cancer, and inhibiting viral replication, and has the potential to control Candida species. Moreover, S. costus has been explored for its capacity to synthesize nanoparticles with antimicrobial properties and for its potential in treating thyroid disorders and liver injury.

Recommendations

Despite promising results, additional research is necessary to fully comprehend the benefits of S. costus and validate its effectiveness in clinical settings. Future research should focus on standardized methodologies and rigorous clinical trials to confirm the safety and effectiveness of S. costus in various medical fields as well as further investigate its biotechnological and pharmaceutical applications.

Effect of polyethoxylated flavonoids (PMFs)-loaded citral and chitosan composite coatings on citrus preservation: From the perspective of fruit resistance

Previous studies have shown that polymethoxylated flavonoids-loaded citral emulsion (PCT) can inhibit the growth and reproduction of Penicillium in citrus; however, PCT is difficult to apply to fruit preservation due to its high fluidity and volatility. Therefore, in this study, we combined PCT with chitosan (CS) to investigate the effect of a composite coating on citrus preservation. The results showed that compared to the control group, the CS-PCT group could effectively reduce the decay rate and maintain moisture availability, color difference, and hardness. Moreover, the contents of nonenzymatic antioxidants and volatile substances with antimicrobial activity were better preserved. In addition, the activities of related antioxidant enzymes were greater in the treatment group, and the expression of the corresponding enzyme-encoding genes was upregulated. Consequently, CS-PCT treatment could effectively maintain fruit quality and improve the resistance of citrus fruits during storage; moreover, it can be considered a nontoxic and efficient citrus preservative.

Advances in sustainable food packaging applications of chitosan/polyvinyl alcohol blend films

Researchers are addressing environmental concerns related to petroleum-based plastic packaging by exploring biopolymers from natural sources, chemical synthesis, and microbial fermentation. Despite the potential of individual biopolymers, they often exhibit limitations like low water resistance and poor mechanical properties. Blending polymers emerges as a promising strategy to overcome these challenges, creating films with enhanced performance. This review focuses on recent advancements in chitosan/polyvinyl alcohol (PVA) blend food packaging films. It covers molecular structure, properties, strategies for performance improvement, and applications in food preservation. The blend's excellent compatibility and intermolecular interactions make it a promising candidate for biodegradable films. Future research should explore large-scale thermoplastic technologies and investigate the incorporation of additives like natural extracts and nanoparticles to enhance film properties. Chitosan/PVA blend films offer a sustainable alternative to petroleum-based plastic packaging, with potential applications in practical food preservation.

Antioxidant potential and factors influencing the content of antioxidant compounds of pepper: A review with current knowledge

The use of natural food items as antioxidants has gained increasing popularity and attention in recent times supported by scientific studies validating the antioxidant properties of natural food items. Peppers (Capsicum spp.) are also important sources of antioxidants and several studies published during the last few decades identified and quantified various groups of phytochemicals with antioxidant capacities as well as indicated the influence of several pre- and postharvest factors on the antioxidant capacity of pepper. Therefore, this review summarizes the research findings on the antioxidant activity of pepper published to date and discusses their potential health benefits as well as the factors influencing the antioxidant activity in pepper. The major antioxidant compounds in pepper include capsaicinoids, capsinoids, vitamins, carotenoids, phenols, and flavonoids, and these antioxidants potentially modulate oxidative stress related to aging and diseases by targeting reactive oxygen and nitrogen species, lipid peroxidation products, as well as genes for transcription factors that regulate antioxidant response elements genes. The review also provides a systematic understanding of the factors that maintain or improve the antioxidant capacity of peppers and the application of these strategies offers options to pepper growers and spices industries for maximizing the antioxidant activity of peppers and their health benefits to consumers. In addition, the efficacy of pepper antioxidants, safety aspects, and formulations of novel products with pepper antioxidants have also been covered with future perspectives on potential innovative uses of pepper antioxidants in the future.

Synthesis of poly (N-isopropyl acrylamide-co-2-acrylamido methylpropane sulfonic acid) hydrogel containing copper and nickel nanoparticles with easy recycling and efficient catalytic potential

Poly(N-isopropyl acrylamide-co-2-acrylamido methyl propane sulfonic acid) hydrogel was prepared and used as matrix for the fabrication of nickel and copper nanoparticles. Nickel and copper nanoparticles were fabricated via in situ reduction of Ni (II) and Cu (II) ions within the hydrogel matrix. The manufactured hydrogel and its corresponding composites with Ni and Cu nanoparticles were characterized by FTIR, XRD, EDX, TEM, and TGA. Thermal stability of hydrogel was found to be increased upon fabricating with metal nanoparticles. The hydrogel showed ability to absorb water 63 times of its weight in dried form. The Ni and Cu nanoparticles were observed to be well dispersed, spherical in shape and most of them were having diameters in the range of 12.5 to 38.8 nm and 58 to 102 nm, respectively. The as-prepared hydrogel-nickel and hydrogel-Cu nanocomposite were used as catalysts for the reduction of a toxic pollutant 4-nitrophenol. At 25 °C, the reduction of 4-NP was found to proceed with apparent rate constant (k app) of 0.107 and 0.122 min−1 in the presence of composite containing Ni and Cu nanoparticles, respectively. However, k app was increased with corresponding increase in temperature and its maximum value was found to be 0.815 min−1 at 88 °C with catalyst containing Ni nanoparticles. The formation of well dispersed Ni and Cu nanoparticles in the prepared hydrogel reflected that this hydrogel system can act as efficient stabilizing agent along with acting as a reactor medium. Recycling potential of catalysts was studied for five successive cycles.

Green synthesis and characterization of copper nanoparticles for investigating their effect on germination and growth of wheat

Today, different types of nanoparticles (NPs) are being synthesized and used for medical and agricultural applications. In this study, copper nanoparticles (CuNPs) were synthesized using the aqueous extract of mint (Mentha longifolia L.). For the characterization of CuNPs, UV-visible spectroscopy, scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectrometry were used. The UV-Visible absorption peak at 558 nm confirmed the formation of CuNPs. The XRD pattern confirmed the phase-centered crystalline nature of CuNPs. FTIR analysis showed the O-H, Cu-H and C-C bonds, indicating the active role of these functional groups as reducing agents of Cu ions to CuNPS. The synthesized NPs were found to have an almost spherical shape with an average size of 23 nm. When applied to wheat, a condition dependent effect of CuNPs was found. Variety 18-Elite Line 1, Elite Line 3, and 18-Elite Line 6 showed maximum germination and growth rate at 50 mg CuNPs/L, while variety 18-Elite Line 5 showed that increase at 25 mg CuNPs/L. Beyond these concentrations, the seed germination and growth of wheat declined. In conclusion, the application of CuNPs showed a beneficial effect in improving the growth of wheat at a certain concentration.

Recent Advancements and Development in Nano-Enabled Agriculture for Improving Abiotic Stress Tolerance in Plants

Abiotic stresses, such as heavy metals (HMs), drought, salinity and water logging, are the foremost limiting factors that adversely affect the plant growth and crop productivity worldwide. The plants respond to such stresses by activating a series of intricate mechanisms that subsequently alter the morpho-physiological and biochemical processes. Over the past few decades, abiotic stresses in plants have been managed through marker-assisted breeding, conventional breeding, and genetic engineering approaches. With technological advancement, efficient strategies are required to cope with the harmful effects of abiotic environmental constraints to develop sustainable agriculture systems of crop production. Recently, nanotechnology has emerged as an attractive area of study with potential applications in the agricultural science, including mitigating the impacts of climate change, increasing nutrient utilization efficiency and abiotic stress management. Nanoparticles (NPs), as nanofertilizers, have gained significant attention due to their high surface area to volume ratio, eco-friendly nature, low cost, unique physicochemical properties, and improved plant productivity. Several studies have revealed the potential role of NPs in abiotic stress management. This review aims to emphasize the role of NPs in managing abiotic stresses and growth promotion to develop a cost-effective and environment friendly strategy for the future agricultural sustainability.

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.

Agronomic Performance, Capsaicinoids, Polyphenols and Antioxidant Capacity in Genotypes of Habanero Pepper Grown in the Southeast of Coahuila, Mexico

The genetic improvement program of the Seed Technology Training and Development Center works on the agronomic characterization and the content of bioactive compounds in eight genotypes of habanero pepper. The objective is to select genotypes with good agronomic performance that allow the generation of inbred lines to obtain hybrids. In this study, the agronomic performance and the content of bioactive compounds (capsaicinoids, polyphenols, and antioxidant capacity) were evaluated in eight genotypes of habanero pepper grown in the southeast of Coahuila, Mexico, identified as HNC-1, HNC-2, HNC-3, HNC-4, HNC-5, HNC-6, HNC-7, and HCC-8. The plants were grown in a greenhouse for 127 days, under a completely randomized design with four replications each. The results revealed that the yield (g·plant−1) and number of fruits per plant did not show significant differences between genotypes. However, for the fruit length, the genotypes HCC-8, HNC-7, HNC-6, and HNC-5 stood out with over 40 mm, while in equatorial diameter of the fruit, HCC-8, HNC-4, and HNC-2 stood out with 26.45, 26.46, and 25.12 mm, respectively. The results of the chemical analyses allowed us to identify that HNC-5 and HNC-6 had the highest capsaicin concentration (931.38 and 959.77 mg·kg−1), dihydrocapsaicin (434.95 and 445.89 mg·kg−1), Scoville Heat Units greater than 210,000, total phenols (67.54 and 71.15 mg/100 g) and total flavonoids (34.21 and 38.29 mg/100 g), respectively. The HNC-1 and HNC-6 genotypes had the highest carotenoids concentration with 103.96 and 105.07 mg/100 g, and HCC-8 registered the highest anthocyanin content with 22.08 mg C3GE/100 g. The antioxidant capacities showed significant differences (p ≤ 0.05) between genotypes, with a range of 43.22 to 110.39 µmol TE/100 g, 72.37 to 186.56 µmol TE/100 g, and 191.41 to 244.98 µmol TE/100 g for the tests of DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2′azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), and FRAP (ferric reducing antioxidant power). The results of this research will be used to select habanero pepper genotypes that can be used in genetic improvement programs to increase the productive potential and the content of bioactive compounds in the fruits to expand their applications in the food industry.

Nutritional Diversity and Antioxidant Activity of Two Indigenous Quince Ecotypes from Rawalakot, Azad Jammu and Kashmir

Quince fruit is mostly used to produce functional products. Recently, the value of this crop has increased due to demand as industrial raw material. The state of Azad Jammu and Kashmir and specifically Rawalakot, District Poonch, is blessed with climatic conditions which are very much suitable for quince production, and therefore, a huge plantation could be found in wild. In this regard, this study was designed to collect two different accessions of quince (apple-shaped quince (ASQ) and pear-shaped quince (PSQ)) from three different locations (Dhamni (elevation: 5431 ft), Shamsabad (elevation: 5374 ft), and Drake (elevation: 3378 ft)) of Rawalakot, District Poonch, and analyze their physicochemical and mineral nutrients of fruit and the soil. Correlation coefficients were established pairwise. Results showed that physicochemical nutrients were significantly ( $P\le 0.05$ ) higher in ASQ fruits as compared with PSQ fruits. Further, fruits collected from location at higher elevation (Dhamni) showed better results as compared with fruits collected from lower elevations. Moreover, increased amount of nitrogen contents in the soil resulted in increased fruit weight. Similarly, fruit quality indices and bioactive compounds showed a positive correlation with the increased soil nutrient contents. These prediction models for quality of quince could be useful in guiding plant nutrition status and for enhancing fruit production in this region.

Synthesis and characterization of glycol chitosan coated selenium nanoparticles acts synergistically to alleviate oxidative stress and increase ginsenoside content in Panax ginseng

The objective of the present study is synthesis of glycol chitosan coated selenium nanoparticles (GC-Se NPs) and evaluation of oxidative stress and ginsenoside accumulation in P. ginseng C. A. Meyer. We synthesized (Se NPs and GC-Se NPs) and characterized using various spectroscopic analyses. The highest concentration (20 mg L^-1) of GC-Se NPs induced moderate ROS (O₂^- and H₂O₂) accumulation and upregulation of PgSOD and PgCAT showing good biocompatibility and less toxicity at the highest concentration. Furthermore, ginsenoside biosynthetic pathway genes (PgHMGR, PgSS, PgSE, PgDDS) also showed significant upregulation upon 20 mg L^-1 GC-Se NPs treatment. At 20 mg L^-1 GC-Se NPs treatment, ginsenoside accumulated upto 217.47 mg/mL and 169.86 mg/mL mainly due to the increased proportion of Rb1 and Re ginsenosides. Altogether, our results suggested that ecofriendly conjugation of GC with Se NPs could be used as a bio fortifier to enhance the ginsenoside profile and to increase the quality of ginseng roots.

Applications of nanotechnology on vegetable crops

Agriculture is the backbone of most developing countries, and most of their people depend on it for their livelihood. The world population is increased by approximately 83 million people each year, so there is a need to increase agricultural productivity. At present, productivity growth can be achieved either by expanding the area cultivated or increasing crop yields through improving the efficiency of fertilizers used. Therefore, there has been a trend to use modern technologies, such as nanotechnology (NT), to increase the productivity of plants. Where, it is involved in the food production process, from planting to packaging. NT improves plants' ability to absorb nutrients, and the agronomic properties of soil, which improves plant growth and productivity. Economically, NT increased the efficiency of nano-fertilizers, and so contributed to increasing productivity and the production of crops. However, the study of the effect of nanotechnology on the environment of soils and plants did not receive the required study. In this review, a comprehensive survey is exhibited on NT as an effective method in dealing with the problem of fertilizer loss during irrigation. This review discusses the technologies and applications of the latest research findings in this field. Furthermore, this review deals with the forms and types of nanoparticles and the methods of their transmission in plants, as well as their effect on plants (physiological and DNA) as well as on those who eat those plants.

Metal/Metal Oxide Nanoparticles: Toxicity, Applications, and Future Prospects

The ever-growing resistance of pathogens to antibiotics and crop disease due to pest has triggered severe health concerns in recent years. Consequently, there is a need of powerful and protective materials for the eradication of diseases. Metal/metal oxide nanoparticles (M/MO NPs) are powerful agents due to their therapeutic effects in microbial infections. In this context, the present review article discusses the toxicity, fate, effects and applications of M/MO NPs. This review starts with an introduction, followed by toxicity aspects, antibacterial and testing methods and mechanism. In addition, discussion on the impact of different M/MO NPs and their characteristics such as size, shape, particle dissolution on their induced toxicity on food and plants, as well as applications in pesticides. Finally, prospective on current and future issues are presented.

Impact of Silicon Nanoparticles on the Antioxidant Compounds of Tomato Fruits Stressed by Arsenic

Tomato fruit is rich in antioxidant compounds such as lycopene and β-carotene. The beneficial effects of the bioactive compounds of tomato fruit have been documented as anticancer activities. The objective of this research was to determine whether arsenic (As) causes changes in the content of antioxidant compounds in tomato fruits and whether Silicon nanoparticles (SiO₂ NPs) positively influence them. The effects on fruit quality and non-enzymatic antioxidant compounds were determined. The results showed that As decreased the oxide-reduction potential (ORP), while lycopene and β-carotene were increased by exposure to As at a low dose (0.2 mg L^-1), and proteins and vitamin C decreased due to high doses of As in the interaction with SiO₂ NPs. A dose of 250 mg L^-1 of SiO₂ NPs increased glutathione and hydrogen peroxide (H₂O₂), and phenols decreased with low doses of As and when they interacted with the NPs. As for the flavonoids, they increased with exposure to As and SiO₂ NPs. The total antioxidant capacity, determined by the ABTS (2,2´-azino-bis[3-ethylbenzthiazolin-6-sulfonic acid]) test, showed an increase with the highest dose of As in the interaction with SiO₂ NPs. The application of As at low doses induced a greater accumulation of bioactive compounds in tomato fruit; however, these compounds decreased in high doses as well as via interaction with SiO₂ NPs, indicating that there was an oxidative burst.

Se Nanoparticles Induce Changes in the Growth, Antioxidant Responses, and Fruit Quality of Tomato Developed under NaCl Stress

Nanotechnology represents an opportunity to improve the use of elements in agriculture. Selenium is an element that is beneficial to plants and essential to the human diet. The size of nanoparticles gives them characteristics that can enhance the benefits that selenium provides to plants. The objective of the present study was to determine the effects of selenium nanoparticles on the growth, antioxidant responses, and fruit quality of tomato developed under NaCl stress. Four doses of selenium nanoparticles (1, 5, 10, and 20 mg L⁻¹) under NaCl stress, only NaCl, and a control were evaluated. The results showed that the impact of salinity on the growth of the tomato crop can be reduced with the application of selenium nanoparticles. However, the amount of both enzymatic and non-enzymatic compounds significantly increased in the leaves and fruits of tomato. The results suggest that the application of selenium nanoparticles generated a positive effect against salinity in the tomato crop; moreover, it had a positive impact on the content of beneficial biocompounds for human health in tomato fruits.

Foliar Application of Zinc Oxide Nanoparticles and Zinc Sulfate Boosts the Content of Bioactive Compounds in Habanero Peppers

The physiological responses of habanero pepper plants (Capsicum chinense Jacq.) to foliar applications of zinc sulphate and zinc nano-fertilizer were evaluated in greenhouse trials. The effect of the supplement on fruit quality of habanero pepper was particularly observed. Habanero pepper plants were grown to maturity, and during the main stages of phenological development, they were treated with foliar applications of Zn at concentrations of 1000 and 2000 mg L-1 in the form of zinc sulfate (ZnSO4) and zinc oxide nanoparticles (ZnO NPs). Additional Zn was not supplied to the control treatment plants. ZnO NPs at a concentration of 1000 mg L-1 positively affected plant height, stem diameter, and chlorophyll content, and increased fruit yield and biomass accumulation compared to control and ZnSO4 treatments. ZnO NPs at 2000 mg L-1 negatively affected plant growth but significantly increased fruit quality, capsaicin content by 19.3%, dihydrocapsaicin by 10.9%, and Scoville Heat Units by 16.4%. In addition, at 2000 ZnO NPs mg L-1 also increased content of total phenols and total flavonoids (soluble + bound) in fruits (14.50% and 26.9%, respectively), which resulted in higher antioxidant capacity in ABTS (2,2'azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), DPPH (2,2-diphenyl-1-picrylhydrazyl), and FRAP (ferric reducing antioxidant power) (15.4%, 31.8%, and 20.5%, respectively). These results indicate that application of ZnO NPs could be employed in habanero pepper production to improve yield, quality, and nutraceutical properties of fruits.

Responses of Tomato Plants under Saline Stress to Foliar Application of Copper Nanoparticles

The tomato crop has great economic and nutritional importance; however, it can be adversely affected by salt stress. The objective of this research is to quantify the agronomic and biochemical responses of tomato plants developed under salt stress with the foliar application of copper nanoparticles. Four treatments were evaluated: foliar application of copper nanoparticles (250 mg L⁻¹) with or without salt stress (50 mM NaCl), salt stress, and an absolute control. Saline stress caused severe damage to the development of tomato plants; however, the damage was mitigated by the foliar application of copper nanoparticles, which increased performance and improved the Na⁺/K⁺ ratio. The content of Cu increased in the tissues of tomato plants under salinity with the application of Cu nanoparticles, which increased the phenols (16%) in the leaves and the content of vitamin C (80%), glutathione (GSH) (81%), and phenols (7.8%) in the fruit compared with the control. Similarly, the enzyme activity of phenylalanine ammonia lyase (PAL), ascorbate peroxidase (APX), glutathione peroxidase (GPX), superoxide dismutase (SOD), and catalase (CAT) increased in leaf tissue by 104%, 140%, 26%, 8%, and 93%, respectively. Foliar spraying of copper nanoparticles on tomatoes under salinity appears to induce stress tolerance to salinity by stimulating the plant’s antioxidant mechanisms.

Impact of Copper Oxide Nanoparticles on Enhancement of Bioactive Compounds Using Cell Suspension Cultures of Gymnema sylvestre (Retz.) R. Br

Gymnema sylvestre is a plant that is enriched in bioactive compounds. In particular, gymnemic acids (GA) and phenolic compounds (PC) are pharmaceutically important. There is a commercial demand for naturally occurring bioactive compounds, but their availability is limited due to geographical and seasonal variations. The elicitation approach can enhance the biosynthesis of phytochemicals during in vitro culture of G. sylvestre. Here, to further improve gymnemic acid II (GA II) and phenolic compounds (PC) production by G. sylvestre, cell suspension cultures (CSC), which has attracted attention for the production of essential phytochemicals, was explored using copper oxide nanoparticles (CuO NPs). Callus was obtained on MS medium containing 2,4-dichlorophenoxyacetic acid, kinetin, phytoagar, and sucrose. Agar-free MS medium was used to initiate CSC, which was treated with three concentrations of CuO NPs (1, 3 or 5 mg/L). Treatment for 48 h with 3 mg/L CuO NPs resulted in the greatest yields of GA II, total phenolics, and flavonoids. The cultures also displayed pronounced antioxidant, antidiabetic, anti-inflammatory, antibacterial, antifungal, and anticancer activities. The use of CuO NPs (3 mg/L) significantly increased the production of GA II (nine-fold) and PC compared to unamended CSC. We propose that CSC and use of nanoparticles (NPs) as a new generation of elicitors, offer a suitable prospect for the production of bioactive compounds.

Chitosan-PVA and Copper Nanoparticles Improve Growth and Overexpress the SOD and JA Genes in Tomato Plants under Salt Stress

Saline stress severely affects the growth and productivity of plants. The activation of hormonal signaling cascades and reactive oxygen species (ROS) in response to salt stress are important for cellular detoxification. Jasmonic acid (JA) and the enzyme SOD (superoxide dismutase), are well recognized markers of salt stress in plants. In this study, the application of chitosan-polyvinyl alcohol hydrogels (Cs-PVA) and copper nanoparticles (Cu NPs) on the growth and expression of defense genes in tomato plants under salt stress was evaluated. Our results demonstrate that Cs-PVA and Cs-PVA + Cu NPs enhance plant growth and also promote the expression of JA and SOD genes in tomato (Solanum lycopersicum L.), under salt stress. We propose that Cs-PVA and Cs-PVA + Cu NPs mitigate saline stress through the regulation of oxidative and ionic stress.

Foliar Application of Cu Nanoparticles Modified the Content of Bioactive Compounds in Moringa oleifera Lam

Moringa oleifera Lam is a plant that has recently gained importance as a food because of its nutritional value and bioactive compound content and because practically all the organs are usable. The use of nanoparticles has appeared as an alternative to increase bioactive compounds in plants. The goal of this work was to determine if the application of copper nanoparticles would increase the content of bioactive compounds and antioxidant capacity in M. oleifera. Copper (Cu) nanoparticles were applied to the leaves at four different times throughout crop growth. The biocompounds were analyzed after the second, third, and fourth applications. The results show that application of Cu nanoparticles has a beneficial effect on the accumulation of bioactive compounds in M. oleifera leaves. In addition, the antioxidant capacity and carotenoid and chlorophyll contents in the leaves of M. oleifera increased after Cu nanoparticles application. The same effect was not observed in the fruit of M. oleifera. Here, the bioactive compound contents diminished. Therefore, the use of Cu nanoparticles can be an important alternative to improve the quality of this plant, particularly that of the leaves.

Effects of Chitosan-PVA and Cu Nanoparticles on the Growth and Antioxidant Capacity of Tomato under Saline Stress

Chitosan is a natural polymer, which has been used in agriculture to stimulate crop growth. Furthermore, it has been used for the encapsulation of nanoparticles in order to obtain controlled release. In this work, the effect of chitosan–PVA and Cu nanoparticles (Cu NPs) absorbed on chitosan–PVA on growth, antioxidant capacity, mineral content, and saline stress in tomato plants was evaluated. The results show that treatments with chitosan–PVA increased tomato growth. Furthermore, chitosan–PVA increased the content of chlorophylls a and b, total chlorophylls, carotenoids, and superoxide dismutase. When chitosan–PVA was mixed with Cu NPs, the mechanism of enzymatic defense of tomato plants was activated. The chitosan–PVA and chitosan–PVA + Cu NPs increased the content of vitamin C and lycopene, respectively. The application of chitosan–PVA and Cu NPs might induce mechanisms of tolerance to salinity.

Use of Chitosan-PVA Hydrogels with Copper Nanoparticles to Improve the Growth of Grafted Watermelon

Modern agriculture requires alternative practices that improve crop growth without negatively affecting the environment, as resources such as water and arable land grow scarcer while the human population continues to increase. Grafting is a cultivation technique that allows the plant to be more efficient in its utilization of water and nutrients, while nanoscale material engineering provides the opportunity to use much smaller quantities of consumables compared to conventional systems but with similar or superior effects. On those grounds, we evaluated the effects of chitosan-polyvinyl alcohol hydrogel with absorbed copper nanoparticles (Cs-PVA-nCu) on leaf morphology and plant growth when applied to grafted watermelon cultivar 'Jubilee' plants. Stomatal density (SD), stomatal index (SI), stoma length (SL), and width (SW) were evaluated. The primary stem and root length, the stem diameter, specific leaf area, and fresh and dry weights were also recorded. Our results demonstrate that grafting induces modifications to leaf micromorphology that favorably affect plant growth, with grafted plants showing better vegetative growth in spite of their lower SD and SI values. Application of Cs-PVA-nCu was found to increase stoma width, primary stem length, and root length by 7%, 8% and 14%, respectively. These techniques modestly improve plant development and growth.