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In conventional chrysanthemum production systems, supplemental lighting is used to induce flowering. Plants perceive radiation in the range of 280 to 750 nm, and UV radiation has been shown to improve plant productivity. Modern technology allows efficient manipulation of these wavelengths, facilitating their direct application to seedlings. This study evaluated the effect of different UV-A exposure times (1, 2, 3 and 4 hours) on chrysanthemum seedlings of the varieties ‘Polaris’ and ‘Codorniz’ (Chrysanthemum × morifolium). In ‘Polaris’, priming the seedlings with UV-A increased growth by 8% and flower diameter by 6%, in addition to improving photosynthesis, with increases of up to 38%. The Fv/Fm index, an indicator of the photochemical efficiency of PSII, increased by 5%. In leaves, β-carotene increased by 45%, vitamin C by 8% and total chlorophylls by 56%. In petals, phenolics increased by 12% and 15%, while flavonoids increased by 12%. In contrast, ‘Codorniz’ showed less sensitivity to UV-A radiation, no change in growth and no change in biochemical compounds, although photosynthesis improved by 20%. UV-A radiation showed great potential for optimizing quality and productivity in chrysanthemums, especially in the ‘Polaris’ variety. These differences highlight the importance of taking into account the specific characteristics of each variety when implementing management strategies using UV-A light.

Nanotechnology has gained importance in agricultural production systems, with various applications such as pesticides or fertilizers. The application of nanomaterials (NMs) as a pretreatment to seeds (seed priming) has positively affected plant growth and development. On the other hand, Moringa oleifera is a plant appreciated for its multiple nutraceutical properties. Therefore, the objective of this study was to evaluate the effect of pretreatment of M. oleifera seeds with ZnO nanoparticles (NZnO) (0, 0.5, 2.5, 5, 7.5, and 10 mg L-1). The study was divided into two experimental phases: the first phase consisted of evaluating germination under laboratory conditions (25 °C) at 15 DAS, while in the second phase, vegetative growth and bioactive compounds were evaluated at 45 DAS under greenhouse conditions. For phase one, the percentage of germination, length, and dry weight of the plumule and radicle were considered, and the vigor indices of seeds were determined. In phase two, we measured the plant height, stem diameter, fresh and dry biomass of aerial and root parts, and the concentration of photosynthetic pigments, phenolic compounds, flavonoids, vitamin C, glutathione (GSH), and antioxidant capacity (DPPH), such as the activity of antioxidant enzymes such as ascorbate peroxidase (APX), catalase (CAT), glutathione peroxidase (GPX), and phenylalanine ammonium lyase (PAL). The results showed an increase in some variables related to seed germination, with an increase of between 30 and 25% in the vigor of the seeds subjected to 2.5 and 10 mg L-1 NZnO. The photosynthetic pigments resulted in increases of between 23 and 49% for the 7.5-10 mg L-1 NZnO treatments. Regarding bioactive compounds, the increase in phenols, flavonoids and vitamin C stands out, mainly at the levels of 7.5-10 mg L-1 NZnO, where increases of up to 543% were observed with respect to the control. The enzymatic activity showed different responses to the application of NZnO, where a biphasic response (hormesis) was observed on the activity of APX and CAT activities as the levels of NZnO increased. The results show that it is possible to promote the initial growth and bioactive compounds of M. oleifera by pretreatment of seeds mainly with 10 mg L-1 NZnO.

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.

Nanotechnology has been proven to be a useful tool in many fields [...]

The potential of Leersia hexandra grass in phytoremediation and natural attenuation of three groups of bacteria in soil contaminated with crude oil was evaluated for 180 days. The quantities of new shoots, root and aerial biomass were evaluated; changes in antioxidant concentrations in leaf and root caused by abiotic stress; population densities of Azotobacter, Azospirillum and Pseudomonas; and microbial respiration. The experimental data showed oil-induced increases of 315% and 196% in new shoots and root phytomass, respectively, and a 44% decrease in leaf + stem phytomass. The enzymatic defence in the grass leaf was manifested by higher concentrations of hydrogen peroxide, phenylalanine ammonium lyase and total flavonoids; the increases fluctuated from 35% to 52%. The response in the root was positive in catalase (16%), and in ammonium phenylalanine lyase, it increased 275% due to the effect of crude oil. The group of indigenous Azotobacter bacteria were tolerant to crude oil exposure, both in the phytoremediation process and in natural attenuation; the population densities varied from 212 to 438 × 103 colony-forming units (CFUs); they are greater than 49% to 106% compared to densities in control soil. Azospirillum spp. and Pseudomonasspp. recorded population abiotic stress. The grass activates enzymatic and plant defence, complementing microbial respiration in response to adaptation to crude oil.

Fungal diseases can cause significant losses in the tomato crop. causes the late blight disease, which considerably affects tomato production worldwide. Weed-based plant extracts are a promising ecological alternative for disease control. In this study, we analyzed the plant extract of L. using chromatography-mass spectrometry analysis (GC-MS). We evaluated its impact on the severity of , as well as its effect on the components of the antioxidant defense system in tomato plants. The extract from contains twelve compounds most have antifungal and biostimulant properties. The findings of the study indicate that applying the extract can reduce the severity of , increase tomato fruit yield, enhance the levels of photosynthetic pigments, ascorbic acid, phenols, and flavonoids, as well as decrease the biosynthesis of H O , malondialdehyde (MDA), and superoxide anion in the leaves of plants infected with this pathogen. These results suggest that using the extract from could be a viable solution to control the disease caused by in tomato crop.

The objective of this work was to determine the responses of tomato seed priming with CNMs (carbon nanomaterials), evaluating the changes in germination and biochemical compounds as well as the effect on the growth of tomato seedlings. Five concentrations of CNMs (10, 100, 250, 500, and 1000 mg L−1) were evaluated, as well as an absolute control and a sonicated control. The results showed that seed priming with CNMs did not affect the germination rate of the tomato seeds; however, it negatively affected the vigor variables, such as the root length (up to 39.2%) and hypocotyl biomass (up to 33%). In contrast, the root biomass was increased by the application of both carbon nanotubes and graphene up to 127% in the best case. Seed priming with carbon nanotubes (1000 mg L−1) decreased the plant height (29%), stem diameter (20%), fresh shoot biomass (63%), fresh root biomass (63%), and dry shoot biomass (71%). Seed priming with graphene increased the content of chlorophylls (up to 111%), vitamin C (up to 78%), β-carotene (up to 11 fold), phenols (up to 85%), and flavonoids (up to 45%), as well as the H2O2 content (up to 215%). Carbon nanotubes (CNTs) increased the enzymatic activity (phenylalanine ammonia lyase (PAL), ascorbate peroxidase (APX), glutathione peroxidase (GPX), superoxide dismutase (SOD), and catalase (CAT). In addition, seed priming with high concentrations of CNMs showed negative effects. Seed priming with carbon nanomaterials can potentially improve the development of the tomato crop; therefore, this technique can be used to induce biostimulation and provides an easy way to apply carbon nanomaterials.

Innovative nano fertilizers based on nanoparticles present great potential for agriculture since they can stimulate growth and development in different crops. However, the efficiency of nanoparticles directly depends on their physicochemical characteristics, such as composition, shape, size, and the type of plant species. In this work, a material formed by mesoporous silica and iron oxide (Fe3O4@MCM-48) was synthesized and used as a nano fertilizer for tomato crop. Materials with different percentages of iron (10, 20, 30, 40, and 50% by weight) were applied to study the effect of the amount of iron in the plants and compared with MCM-48 without iron and ferric chloride hexahydrate. Using X-ray diffraction (XRD), it was possible to identify the phases present in the system, and with Transmission Electron Microscopy (TEM), it was observed that the material is made up of a matrix of MCM-48 with embedded Fe3O4 nanoparticles with a size of 5 nm. Also, the results show that all treatments with nano fertilizers increased the content of photosynthetic pigments and carotenoids in leaves. The use of nano fertilizers can be a viable option to improve the crop growth and efficiency of nutrient use in plants.

The diseases that attack the tomato crop are a limiting factor for its production and are difficult to control or eradicate. Stem and fruit rot and leaf blight caused by Alternaria solani causes severe damage and substantial yield losses. Carbon nanotubes (CNTs) could be an alternative for the control of pathogens since they have strong antimicrobial activity, in addition to inducing the activation of the antioxidant defense system in plants. In the present study, multi-walled carbon nanotubes were evaluated on the incidence and severity of A. solani. Moreover, to the impact they have on the antioxidant defense system and the photosynthetic capacity of the tomato crop. The results show that the application of CNTs had multiple positive effects on tomato crop. CNTs decreased the incidence and severity of A. solani. Furthermore, CNTs increased the fruit yield of tomato crop and dry shoot biomass. The antioxidant system was improved, since the content of ascorbic acid, flavonoids, and the activity of the glutathione peroxidase enzyme were increased. The net photosynthesis and water use efficiency were also increased by the application of CNTs. CNTs can be an option to control A. solani in tomato crop, and diminish the negative impact of this pathogen.

The consumption of food with a high content of bioactive compounds is correlated with the prevention of chronic degenerative diseases. Tomato is a food with exceptional nutraceutical value; however, saline stress severely affects the yield, the quality of fruits, and the agricultural productivity of this crop. Recent studies have shown that seed priming can mitigate or alleviate the negative effects caused by this type of stress. However, the use of carbon nanomaterials (CNMs) in this technique has not been tested for this purpose. In the present study, the effects of tomato seed priming with carbon nanotubes (CNTs) and graphene (GP) (50, 250, and 500 mg L−1) and two controls (not sonicated and sonicated) were evaluated based on the content of photosynthetic pigments in the leaves; the physicochemical parameters of the fruits; and the presence of enzymatic and non-enzymatic antioxidant compounds, carotenoids, and stress biomarkers such as hydrogen peroxide (H2O2) and malondialdehyde (MDA) in the leaves and fruits of tomato plants without saline stress and with saline stress (50 mM NaCl). The results show that saline stress in combination with CNTs and GP increased the content of chlorophylls (9.1–21.7%), ascorbic acid (19.5%), glutathione (≈13%), proteins (9.9–11.9%), and phenols (14.2%) on the leaves. The addition of CNTs and GP increased the activity of enzymes (CAT, APX, GPX, and PAL). Likewise, there was also a slight increase in the content of H2O2 (by 20.5%) and MDA (3.7%) in the leaves. Salinity affected the quality of tomato fruits. The physico-chemical parameters and bioactive compounds in both the stressed and non-stressed tomato plants were modified with the addition of CNTs and GP. Higher contents of total soluble solids (25.9%), phenols (up to 144.85%), flavonoids (up to 37.63%), ascorbic acid (≈28%), and lycopene (12.4–36.2%) were observed. The addition of carbon nanomaterials by seed priming in tomato plants subjected to saline stress modifies the content of bioactive compounds in tomato fruits and improves the antioxidant defense system, suggesting possible protection of the plant from the negative impacts of stress by salinity. However, analysis of the mechanism of action of CNMs through seed priming, in greater depth is suggested, perhaps with the use of omics sciences.