Nanotechnology is a potential and emerging field with multiple applications in different areas of study. The beneficial effects of the use of nanoparticles in agriculture have already been proven. The objective of this research was to determine if the foliar application of Cu nanoparticles (NPs) could increase the content of the bioactive compounds in tomato fruits. Our study considered four treatments with different concentrations of Cu nanoparticles (50, 125, 250, 500 mg L⁻¹, diameter 50 nm) applied twice during the development of the culture. The effects on the fruit quality and the contents of the antioxidant compounds were determined. The application of the Cu nanoparticles induced the production of fruits with greater firmness. Vitamin C, lycopene, and the ABTS antioxidant capacity increased compared to the Control. In addition, a decrease in the ascorbate peroxidase (APX) and glutathione peroxidase (GPX) enzymatic activity was observed, while the superoxide dismutase (SOD) and catalase (CAT) enzymes showed a significant increase. The application of Cu NPs induced a greater accumulation of bioactive compounds in tomato fruits.

The effects of nanoparticles (NPs) on plants are contrasting; these depend on the model plant, the synthesis of the nanoparticles (concentration, size, shape), and the forms of application (foliar, substrate, seeds). For this reason, the objective of this study was to report the impact of different concentrations of selenium (Se) and copper (Cu) NPs on yield, antioxidant capacity, and quality of tomato fruit. The different concentrations of Se and Cu NPs were applied to the substrate every 15 days (five applications). The yield was determined until day 102 after the transplant. Non-enzymatic and enzymatic antioxidant compounds were determined in the leaves and fruits as well as the fruit quality at harvest. The results indicate that tomato yield was increased by up to 21% with 10 mg L⁻¹ of Se NPs. In leaves, Se and Cu NPs increased the content of chlorophyll, vitamin C, glutathione, 2,2′-azino-bis(3-ethylbenzthiazolin-6-sulfonic acid (ABTS), superoxide dismutase (SOD), glutathione peroxidase (GPX) and phenylalanine ammonia liasa (PAL). In fruits, they increased vitamin C, glutathione, flavonoids, firmness, total soluble solids, and titratable acidity. The combination of Se and Cu NPs at optimal concentrations could be a good alternative to improve tomato yield and quality, but more studies are needed to elucidate their effects more clearly.

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.

Early blight is a disease that greatly affects Solanaceae, mainly damaging tomato plants, and causing significant economic losses. Although there are methods of biological control, these are very expensive and often their mode of action is slow. Due to this, there is a need to use new techniques that allow a more efficient control of pathogens. Nanotechnology is a new alternative to solve these problems, allowing the creation of new tools for the treatment of diseases in plants, as well as the control of pathogens. The aim of the present investigation was to evaluate the foliar application of selenium and copper in the form of nanoparticles in a tomato crop infested by Alternaria solani. The severity of Alternaria solani, agronomic variables of the tomato crop, and the changes in the enzymatic and non-enzymatic antioxidant compounds were evaluated. The joint application of Se and Cu nanoparticles decreases the severity of this pathogen in tomato plants. Moreover, high doses generated an induction of the activity of the enzymes superoxide dismutase, ascorbate peroxidase, glutathione peroxidase (GPX) and phenylalanine ammonia lyase in the leaves, and the enzyme GPX in the fruit. Regarding non-enzymatic compounds in the leaves, chlorophyll a, b, and totals were increased, whereas vitamin C, glutathione, phenols, and flavonoids were increased in fruits. The application of nanoparticles generated beneficial effects by increasing the enzymatic and non-enzymatic compounds and decreasing the severity of Alternaria solani in tomato plants.

The bell pepper is a vegetable with high antioxidant content, and its consumption is important because it can reduce the risk of certain diseases in humans. Plants can be affected by different types of stress, whether biotic or abiotic. Among the abiotic factors, there is saline stress that affects the metabolism and physiology of plants, which causes damage, decreasing productivity and quality of fruits. The objective of this work was to evaluate the application of selenium, silicon and copper nanoparticles and saline stress on the bioactive compounds of bell pepper fruits. The bell pepper plants were exposed to saline stress (25 mM NaCl and 50 mM) in the nutrient solution throughout the crop cycle. The nanoparticles were applied drenching solution of these to substrate (Se NPs 10 and 50 mg L⁻¹, Si NPs 200 and 1000 mg L⁻¹, Cu NPs 100 and 500 mg L⁻¹). The results show that saline stress reduces chlorophylls, lycopene, and β-carotene in leaves; but increased the activity of some enzymes (e.g., glutathione peroxidase and phenylalanine ammonia lyase, and glutathione). In fruits, saline stress decreased flavonoids and glutathione. The nanoparticles increased chlorophylls, lycopene and glutathione peroxidase activity in the leaves; and ascorbate peroxidase, glutathione peroxidase, catalase and phenylalanine ammonia lyase activity, and also phenols, flavonoids, glutathione, β-carotene, yellow carotenoids in fruits. The application of nanoparticles to bell pepper plants under saline stress is efficient to increase the content of bioactive compounds in fruits.

The objective of this review is to present a compilation of the application of various biostimulants in strawberry plants. Strawberry cultivation is of great importance worldwide, and, there is currently no review on this topic in the literature. Plant biostimulation consists of using or applying physical, chemical, or biological stimuli that trigger a response—called induction or elicitation—with a positive effect on crop growth, development, and quality. Biostimulation provides tolerance to biotic and abiotic stress, and more absorption and accumulation of nutrients, favoring the metabolism of the plants. The strawberry is a highly appreciated fruit for its high organoleptic and nutraceutical qualities since it is rich in phenolic compounds, vitamins, and minerals, in addition to being a product with high commercial value. This review aims to present an overview of the information on using different biostimulation techniques in strawberries. The information obtained from publications from 2000–2022 is organized according to the biostimulant’s physical, chemical, or biological nature. The biochemical or physiological impact on plant productivity, yield, fruit quality, and postharvest life is described for each class of biostimulant. Information gaps are also pointed out, highlighting the topics in which more significant research effort is necessary.