Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 84
Filter
1.
Nano Lett ; 24(17): 5110-5116, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38624179

ABSTRACT

The remarkable development of colloidal nanocrystals with controlled dimensions and surface chemistry has resulted in vast optoelectronic applications. But can they also form a platform for quantum materials, in which electronic coherence is key? Here, we use colloidal, two-dimensional Bi2Se3 crystals, with precise and uniform thickness and finite lateral dimensions in the 100 nm range, to study the evolution of a topological insulator from three to two dimensions. For a thickness of 4-6 quintuple layers, scanning tunneling spectroscopy shows an 8 nm wide, nonscattering state encircling the platelet. We discuss the nature of this edge state with a low-energy continuum model and ab initio GW-Tight Binding theory. Our results also provide an indication of the maximum density of such states on a device.

2.
Small ; 20(9): e2304925, 2024 Mar.
Article in English | MEDLINE | ID: mdl-37857590

ABSTRACT

Manganese is an attractive element for sustainable solutions. It is largely available in the earth's crust, making it ideal for cost-effective and large-scale applications. Especially MnO nanoparticles have recently received attention for applications in battery technology. However, manganese has many oxidation states that are energetically very similar, indicating that they may easily transform from one to the other. Herein, the reversible oxidation of MnO nanoparticles to Mn3 O4 studied with in situ transmission electron microscopy is shown. The oxygen sublattices of MnO and Mn3 O4 are found to be perfectly aligned, and an atomic mechanism where the transformation is facilitated by the migration of Mn cations on the shared O sublattice is proposed. Even when protected with an amorphous carbon layer, MnO particles are highly unstable and oxidize to Mn3 O4 in ethanol. The poor stability of MnO lacks discussion in many battery-related works, and strategies aimed at avoiding this should be developed.

3.
Environ Sci Pollut Res Int ; 30(54): 115381-115395, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37884726

ABSTRACT

This article evaluated the effect of using mining waste on the mechanical, physical, thermal, and microstructural properties of cement-wood panels. The percentages of 10, 20, 30, and 40% were evaluated as replacing cement with mining waste. The wood particles of Pinus oocarpa were evaluated for their chemical, anatomical, and physical characteristics, and the mining waste was evaluated for its granulometry, chemical composition, and inhibition index. The composites were evaluated for their physical-mechanical properties, X-ray diffraction and infrared spectroscopy analysis, microstructural, thermal, and durability. All evaluated treatments met the requirements of the Bison standard for MOR and MOE for static bending and internal bonding, even after accelerated aging. It was possible to conclude that it is feasible to replace 40% of cement with mining waste for the production of cement-wood panels in industrial scale.


Subject(s)
Pinus , Wood , Industry , Mining , Iron/chemistry
4.
Biotechnol Adv ; 68: 108223, 2023 11.
Article in English | MEDLINE | ID: mdl-37536466

ABSTRACT

Agricultural systems are in need of low-cost, safe antibiotics to protect crops from pests and diseases. Peptaibiotics, a family of linear, membrane-active, amphipathic polypeptides, have been shown to exhibit antibacterial, antifungal, and antiviral activity, and to be inducers of plant resistance against a wide range of phytopathogens. Peptaibiotics belong to the new generation of alternatives to agrochemicals, aligned with the United Nations Sustainable Development Goals and the One Health approach toward ensuring global food security and safety. Despite that, these fungi-derived, non-ribosomal peptides remain surprisingly understudied, especially in agriculture, where only a small number has been tested against a reduced number of phytopathogens. This lack of adoption stems from peptaibiotics' poor water solubility and the difficulty to synthesize and purify them in vitro, which compromises their delivery and inclusion in formulations. In this review, we offer a comprehensive analysis of peptaibiotics' classification, biosynthesis, relevance to plant protection, and mode of action against phytopathogens, along with the techniques enabling researchers to extract, purify, and elucidate their structure, and the databases holding such valuable data. It is also discussed how chemical synthesis and ionic liquids could increase their solubility, how genetic engineering and epigenetics could boost in vitro production, and how omics can reduce screenings' workload through in silico selection of the best candidates. These strategies could turn peptaibiotics into effective, ultra-specific, biodegradable tools for phytopathogen control.


Subject(s)
Anti-Bacterial Agents , Peptides , Peptides/pharmacology , Anti-Bacterial Agents/pharmacology , Fungal Proteins , Crops, Agricultural
5.
PeerJ ; 11: e15525, 2023.
Article in English | MEDLINE | ID: mdl-37397024

ABSTRACT

Backgorund: The production of red fruits, such as blueberry, has been threatened by several stressors from severe periods of drought, nutrient scarcity, phytopathogens, and costs with fertilization programs with adverse consequences. Thus, there is an urgent need to increase this crop's resilience whilst promoting sustainable agriculture. Plant growth-promoting microorganisms (PGPMs) constitute not only a solution to tackle water and nutrient deficits in soils, but also as a control against phytopathogens and as green compounds for agricultural practices. Methods: In this study, a metagenomic approach of the local fungal and bacterial community of the rhizosphere of Vaccinium corymbosum plants was performed. At the same time, both epiphytic and endophytic microorganisms were isolated in order to disclose putative beneficial native organisms. Results: Results showed a high relative abundance of Archaeorhizomyces and Serendipita genera in the ITS sequencing, and Bradyrhizobium genus in the 16S sequencing. Diversity analysis disclosed that the fungal community presented a higher inter-sample variability than the bacterial community, and beta-diversity analysis further corroborated this result. Trichoderma spp., Bacillus spp., and Mucor moelleri were isolated from the V. corymbosum plants. Discussion: This work revealed a native microbial community capable of establishing mycorrhizal relationships, and with beneficial physiological traits for blueberry production. It was also possible to isolate several naturally-occurring microorganisms that are known to have plant growth-promoting activity and confer tolerance to hydric stress, a serious climate change threat. Future studies should be performed with these isolates to disclose their efficiency in conferring the needed resilience for this and several crops.


Subject(s)
Blueberry Plants , Mycorrhizae , Blueberry Plants/microbiology , Rhizosphere , Portugal , Mycorrhizae/physiology , Crops, Agricultural/microbiology , Bacteria
6.
Insects ; 14(6)2023 Jun 07.
Article in English | MEDLINE | ID: mdl-37367349

ABSTRACT

The spotted-wing drosophila (Drosophila suzukii) is a polyphagous pest that causes severe damage and economic losses to soft-skinned fruit production. Current control methods are dominated by inefficient cultural practices and broad-spectrum insecticides that, in addition to having toxic effects on non-target organisms, are becoming less effective due to acquired resistance. The increasing awareness of the real impact of insecticides on health and the environment has promoted the exploration of new insecticidal compounds, addressing novel molecular targets. This study explores the efficacy of two orally delivered spider venom peptides (SVPs), J-atracotoxin-Hv1c (Hv1c) and µ-theraphotoxin-Hhn2b (TRTX), to manage D. suzukii, through survival assays and the evaluation of gene expression associated with detoxification pathways. Treatment with TRTX at 111.5 µM for 48 h enhanced fly longevity compared with the control group. Gene expression analysis suggests that detoxification and stress-related mechanisms, such as expression of P450 proteins and apoptotic stimuli signaling, are triggered in D. suzukii flies in response to these treatments. Our results highlight the potential interest of SVPs to control this pest, shedding light on how to ultimately develop improved target-specific formulations.

7.
Article in Portuguese | LILACS-Express | LILACS, Index Psychology - journals | ID: biblio-1530202

ABSTRACT

As lesões autoprovocadas são investigadas a partir da escuta psicanalítica de 15 adolescentes que chegaram a um ambulatório público. O sofrimento psíquico na adolescência contemporânea apresenta-se com crescente frequência sob a forma desse tipo de problema. A medicalização, que tem sido uma resposta dominante para esses jovens, é avaliada criticamente. Explora-se, com a ajuda do referencial psicanalítico, outros tipos de entendimento da questão, recorrendo-se às teorias freudianas sobre angústia, dor e formação de sintomas. Usando os aportes lacanianos, são destacados, também, os efeitos da palavra e da voz do Outro sobre o sujeito adolescente. Dois jovens transgêneros que apresentavam histórico de autoagressão conduziram a reflexões específicas sobre o tema.


Self-inflicted lesions are examined from the perspective of psychoanalytic listening to fifteen adolescents who sought help at a walk-in clinic. Psychological suffering among contemporary adolescents often presents in the guise of this problem. Medicalization is critically assessed as the predominant response to such youths. Aided by psychoanalytic references, other modes of understanding the problem are explored, and Freudian theories of anxiety, pain, and symptom formation are deployed. Additionally, Lacanian theory is called upon to highlight the effects of the word and voice of the Other upon the adolescent subject. Two transgender youths presenting with histories of self-aggression lead to specific reflections on the issue.


Les automutilations sont étudiées à partir de l'écoute psychanalytique de 15 adolescents arrivés en centre ambulatoire. La souffrance psychique de l'adolescence contemporaine se manifeste de plus en plus fréquemment sous cette forme. La médicalisation, qui a été la solution majoritairement adoptée pour ces jeunes, est considérée sous un jour critique. Sont explorées, à l'aide du référentiel psychanalytique, d'autres formes de compréhension de cette problématique, grâce aux théories freudiennes sur l'angoisse, la douleur et la formation des symptômes. Faisant usage des apports lacaniens, sont également mis en relief les effets de la parole et de la voix de l'Autre sur le sujet adolescent. Deux jeunes transgenres présentant un historique d'automutilations ont conduit à des réflexions spécifiques sur le sujet.


Se investigan las autolesiones a partir de la escucha psicoanalítica de 15 jóvenes que fueron acudidos en ambulatorio público. El sufrimiento psíquico en la adolescencia contemporánea se presenta cada vez con mayor frecuencia en forma de este tipo de problemas. La medicalización, que ha sido una respuesta dominante para estos jóvenes, es evaluada críticamente. Con la ayuda del marco psicoanalítico, se exploran otras maneras de comprensión del problema, utilizando las teorías freudianas sobre la angustia, el dolor y la formación de síntomas. Con los aportes lacanianos, también se destacan los efectos de la palabra y la voz del Otro en el sujeto adolescente. Dos jóvenes transgénero que tenían un historial de autolesiones llevaron a reflexiones específicas sobre el tema.

8.
Sci Rep ; 12(1): 21194, 2022 12 07.
Article in English | MEDLINE | ID: mdl-36476948

ABSTRACT

As a polyphagous pest, Drosophila suzukii has a variety of host fruits available for feeding and oviposition, but how the nutritional geometry of different hosts influences its metabolism is still poorly understood. This work aimed to evaluate how D. suzukii metabolic and transcriptional pathways are influenced by feeding on different host fruits, and how sex influences these responses. Adult flies were allowed to feed on five different fruit-based media. Lipids, glucose, glycogen, and energy pathways-associated gene expression, were quantified. Females showed an energetic metabolism easily adaptable to the food's nutritional characteristics; in contrast, males' energetic metabolism was particularly influenced by food, predominantly those fed on raspberry media who showed changes in glucose levels and in the expression of genes associated with metabolic pathways, suggesting activation of gluconeogenesis and trehaloneogenesis as a result of nutritional deficiency. Here we present novel insight into how D. suzukii's energetic pathways are modulated depending on fruits' nutritional geometry and sex. While the females showed high adaptability in their energetic metabolism to the diet, males were more feeding-sensitive. These findings might be used not only to control this pest population but to better advise producers to invest in less suitable fruits based on the hosts' nutritional geometry.


Subject(s)
Drosophila , Female , Animals
9.
Food Res Int ; 162(Pt A): 111914, 2022 12.
Article in English | MEDLINE | ID: mdl-36461183

ABSTRACT

Colorimetric films incorporated with anthocyanins as an indicator for freshness monitoring have aroused growing interest recently. The pH-sensing colorimetric film were developed based on pectin (HM), containing aqueous hibiscus extract microparticles (HAE). HAE microparticles were obtained by spray drying with different wall materials (Inulin -IN, maltodextrin- MD and their combination). The films were obtained on large scale by continuous casting. These films were characterized for physicochemical analysis, morphological structure, thermal and barrier properties, antioxidant activity, and color change at different pH. The addition of HAE microparticles caused relevant changes to HM-based films, such as in mechanical behavior and improved barrier property (11-22% WVTR reduction) depending on the type of wall material used and the concentration added. It was verified with the thermal stability of films, with a slight increase being observed. The color variation of smart films was entirely pH-dependent. Overall, the proposed color indicator films showed unique features and functionalities and could be used as an alternative natural pH indicator in smart packaging systems.


Subject(s)
Hibiscus , Anthocyanins , Pectins , Spray Drying
10.
PeerJ ; 10: e13695, 2022.
Article in English | MEDLINE | ID: mdl-35891645

ABSTRACT

Background: Fire blight is a destructive disease of pome trees, caused by Erwinia amylovora, leading to high losses of chain-of-values fruits. Major outbreaks were registered between 2010 and 2017 in Portugal, and the first molecular epidemiological characterization of those isolates disclosed a clonal population with different levels of virulence and susceptibility to antimicrobial peptides. Methods: This work aimed to further disclose the genetic characterization and unveil the phenotypic diversity of this E. amylovora population, resorting to MLSA, growth kinetics, biochemical characterization, and antibiotic susceptibility. Results: While MLSA further confirmed the genetic clonality of those isolates, several phenotypic differences were recorded regarding their growth, carbon sources preferences, and chemical susceptibility to several antibiotics, disclosing a heterogeneous population. Principal component analysis regarding the phenotypic traits allows to separate the strains Ea 630 and Ea 680 from the remaining. Discussion: Regardless the genetic clonality of these E. amylovora strains isolated from fire blight outbreaks, the phenotypic characterization evidenced a population diversity beyond the genotype clonality inferred by MLSA and CRISPR, suggesting that distinct sources or environmental adaptations of this pathogen may have occurred. Conclusion: Attending the characteristic clonality of E. amylovora species, the data gathered here emphasizes the importance of phenotypic assessment of E. amylovora isolates to better understand their epidemiological behavior, namely by improving source tracking, make risk assessment analysis, and determine strain-specific environmental adaptations, that might ultimately lead to prevent new outbreaks.


Subject(s)
Erwinia amylovora , Erwinia amylovora/genetics , Fruit , Anti-Bacterial Agents , Virulence/genetics , Phenotype
12.
Natl Sci Rev ; 9(5): nwab153, 2022 May.
Article in English | MEDLINE | ID: mdl-35591917

ABSTRACT

Two-dimensional (2D) rare-earth oxides (REOs) are a large family of materials with various intriguing applications and precise facet control is essential for investigating new properties in the 2D limit. However, a bottleneck remains with regard to obtaining their 2D single crystals with specific facets because of the intrinsic non-layered structure and disparate thermodynamic stability of different facets. Herein, for the first time, we achieve the synthesis of a wide variety of high-quality 2D REO single crystals with tailorable facets via designing a hard-soft-acid-base couple for controlling the 2D nucleation of the predetermined facets and adjusting the growth mode and direction of crystals. Also, the facet-related magnetic properties of 2D REO single crystals were revealed. Our approach provides a foundation for further exploring other facet-dependent properties and various applications of 2D REO, as well as inspiration for the precise growth of other non-layered 2D materials.

13.
Environ Sci Pollut Res Int ; 29(32): 48964-48974, 2022 Jul.
Article in English | MEDLINE | ID: mdl-35201586

ABSTRACT

This study aimed to evaluate the effect of using expanded vermiculite and its impact on the production of concrete roof tiles. The control treatment and replacement of 12.5, 25, 37.5, and 50% sand by vermiculite were evaluated. The concrete roof tiles were moulded by the simultaneous pressing and extrusion mechanical process. The control trace was comprised by 21.95% CPV-ARI cement, 65.85% sand, and 12.20% limestone. After production, the concrete roof tiles were cured for 28 days. The physical (roof tiles classification, samples dry weight, water absorption, and porosity), mechanical (splitting tensile strength), and microstructural properties were evaluated. All treatments were assessed before and after accelerated ageing. The thermal properties of the modification in the concrete roof tiles' composition were also analysed. The evaluated amounts of vermiculite significantly affected the physical, mechanical, and thermal properties of concrete roof tiles. The use of vermiculite in concrete roof tiles reduced their dry weight and thermal conductivity, not impairing their durability. The use of 31.0% vermiculite in concrete roof tiles was suggested for better thermal insulation optimization (20.29% reduction) and weight reduction (7.92% and 7.94% at 28 days of curing and after accelerated ageing, respectively), along with adequate physical, mechanical, and durability properties.


Subject(s)
Construction Materials , Sand , Aluminum Silicates , Construction Materials/analysis , Thermal Conductivity
14.
Plants (Basel) ; 11(4)2022 Feb 09.
Article in English | MEDLINE | ID: mdl-35214801

ABSTRACT

Cases of weed resistant to herbicides have changed the dynamics of agricultural areas in Brazil, and in recent years, Erigeron species have caused major problems to farmers in the country, mainly in relation to the ineffectiveness of herbicide treatments used. The objective of this study was to confirm the cross-resistance to ALS inhibitors in populations of Erigeron sumatrensis as well as to investigate the existence of mutations in the site of action of ALS-inhibiting herbicides. To do this, 30 populations collected in the 2016/2017 crop season were grown in a greenhouse. Dose-response (chlorimuron-ethyl and cloransulam-methyl), inhibition of cytochrome P-450 with malathion, and ALS gene sequencing experiments were carried out in the F1 generations of two fleabane populations. The results proved the cross-resistance to chlorimuron-ethyl and cloransulam-methyl herbicides applied in the post-emergence of the resistant population of E. sumatrensis. The higher activity of P450 enzymes is unlikely responsible for the resistance of the population studied. The resistance mechanism found in R was the target site mutation Pro197Ser at the ALS gene. This is the first study in Brazil to identify a target-site change as a survival mechanism in E. sumatrensis for the resistance to ALS-inhibiting herbicides.

15.
Environ Sci Pollut Res Int ; 29(14): 21034-21048, 2022 Mar.
Article in English | MEDLINE | ID: mdl-34748178

ABSTRACT

This research aimed to evaluate the effect of adding different polymeric waste percentages and types on the physical, mechanical, thermal, and durability properties of soil-cement bricks. Tire and polyethylene terephthalate (PET) waste were evaluated at 1.5 and 3.0% (mass/mass). The soil was characterized in terms of shrinkage, compaction, consistency limits, particle size, and chemical analyses, whereas the waste particles were submitted to morphological characterization. The bricks were produced in an automatic press with a 90:10 (mass/mass) soil:cement ratio. The soil-cement bricks were characterized by density, moisture, water absorption, loss of mass by immersion, compressive strength, thermal conductivity, and microstructural analysis. PET waste stood out for its use as reinforcement in soil-cement bricks. The best performance was obtained for bricks reinforced with 1.5% PET, which showed a significant compressive strength improvement, meeting the marketing standards criteria, even after the durability test, as well as obtaining the lowest thermal conductivity values. The percentage increase from 1.5 to 3.0% fostered a significant water absorption and loss of mass increase, as well as a significant compressive strength reduction of the bricks.


Subject(s)
Construction Materials , Soil , Compressive Strength , Construction Materials/analysis , Polyethylene Terephthalates , Thermal Conductivity
16.
Environ Sci Pollut Res Int ; 29(15): 21769-21788, 2022 Mar.
Article in English | MEDLINE | ID: mdl-34773234

ABSTRACT

The need for environmental preservation requires civil engineering to reach new concepts and technical solutions aiming at the sustainability of its activities and products. In this context, this study aimed to evaluate the effect of using different types and percentages of vegetable particles on the physical, mechanical, and thermal properties of soil-cement bricks. Bamboo, rice husk, and coffee husk particles at 1.5 and 3% percentages and a control treatment not using the particle were evaluated. The chemical properties, shrinkage, compaction, consistency limits, and grain size were characterized for the soil; and the anatomical, chemical, and physical properties for the lignocellulosic particles. The bricks were produced using an automatic press and characterized after the curing process for density, water absorption, porosity, loss of mass by immersion, compressive strength, durability, and thermal conductivity. The increase in the lignocellulosic waste percentage caused a mechanical strength decrease and bricks' porosity and water absorption increase. However, it caused a decrease in density and an enhancement in loss of mass and thermal insulation properties. The bricks produced with rice husk obtained the best results in terms of mechanical and thermal properties, and were still among the best treatments for physical properties, standing out among the lignocellulosic waste as an alternative raw material source for soil-cement brick production.


Subject(s)
Construction Materials , Soil , Compressive Strength , Lignin , Thermal Conductivity
17.
Clin Exp Neuroimmunol ; 13(2): 92-94, 2022 May.
Article in English | MEDLINE | ID: mdl-34900000

ABSTRACT

Background: Guillain-Barré syndrome (GBS) is an acute monophasic immune-mediated polyradiculoneuropathy, preceded by gastrointestinal or respiratory infections in up to two-thirds of patients. On rare occasions, people develop GBS after vaccination, but no causal association has been proven. In the current coronavirus disease 2019 (COVID-19) pandemic, some cases have been reported associating COVID-19 vaccine with GBS. Case presentation: We report a case of a 62-year-old woman with GBS after the first dose of the Oxford/AstraZeneca vaccine against SARS-CoV-2. The symptoms started 3 weeks after the vaccine, and were characterized by ascending and progressive paresthesia in the upper and lower limbs, followed by loss of strength of the upper limbs and dysphagia for solids. The hypothesis of GBS was confirmed by clinical presentation compatible with albuminocytologic dissociation in cerebrospinal fluid and based on the Brighton criteria level 2. The treatment was a 5-day course of intravenous immunoglobulin with an improvement of symptoms. Conclusions: In the absence of other causes, the diagnosis of GBS was made, with evidence of a clear temporal association with COVID-19 vaccine. However, a cautious position is important when assigning a particular side-effect directly to a vaccine. It is important to emphasize that it is a temporal association only and the benefits of COVID-19 vaccination continue to outweigh the possible consequences.

18.
Plants (Basel) ; 10(12)2021 Nov 30.
Article in English | MEDLINE | ID: mdl-34961108

ABSTRACT

Fire blight is a severe bacterial plant disease that affects important chain-of-value fruit trees such as pear and apple trees. This disease is caused by Erwinia amylovora, a quarantine phytopathogenic bacterium, which, although highly distributed worldwide, still lacks efficient control measures. The green revolution paradigm demands sustainable agriculture practices, for which antimicrobial peptides (AMPs) have recently caught much attention. The goal of this work was to disclose the bioactivity of three peptides mixtures (BP100:RW-BP100, BP100:CA-M, and RW-BP100:CA-M), against three strains of E. amylovora representing distinct genotypes and virulence (LMG 2024, Ea 630 and Ea 680). The three AMPs' mixtures were assayed at eight different equimolar concentrations ranging from 0.25 to 6 µM (1:1). Results showed MIC and MBC values between 2.5 and 4 µM for every AMP mixture and strain. Regarding cell viability, flow cytometry and alamarBlue reduction, showed high reduction (>25%) of viable cells after 30 min of AMP exposure, depending on the peptide mixture and strain assayed. Hypersensitive response in tobacco plants showed that the most efficient AMPs mixtures and concentrations caused low to no reaction of the plant. Altogether, the AMPs mixtures studied are better treatment solutions to control fire blight disease than the same AMPs applied individually.

19.
Adv Sci (Weinh) ; 8(20): e2100619, 2021 Oct.
Article in English | MEDLINE | ID: mdl-34459155

ABSTRACT

In recent years, two-dimensional (2D) materials have attracted a lot of research interest as they exhibit several fascinating properties. However, outside of 2D materials derived from van der Waals layered bulk materials only a few other such materials are realized, and it remains difficult to confirm their 2D freestanding structure. Despite that, many metals are predicted to exist as 2D systems. In this review, the authors summarize the recent progress made in the synthesis and characterization of these 2D metals, so called metallenes, and their oxide forms, metallene oxides as free standing 2D structures formed in situ through the use of transmission electron microscopy (TEM) and scanning TEM (STEM) to synthesize these materials. Two primary approaches for forming freestanding monoatomic metallic membranes are identified. In the first, graphene pores as a means to suspend the metallene or metallene oxide and in the second, electron-beam sputtering for the selective etching of metal alloys or thick complex initial materials is employed to obtain freestanding single-atom-thick 2D metal. The data show a growing number of 2D metals/metallenes and 2D metal/ metallene oxides having been confirmed and point to a bright future for further discoveries of these 2D materials.

20.
Plants (Basel) ; 10(5)2021 May 03.
Article in English | MEDLINE | ID: mdl-34063679

ABSTRACT

Daily UV-supplementation during the plant fruiting stage of tomato (Solanum lycopersicum L.) growing indoors may produce fruits with higher nutraceutical value and better acceptance by consumers. However, it is important to ensure that the plant's performance during this stage is not compromised by the UV supplement. We studied the impact of UV-A (1 and 4 h) and UV-B (2 and 5 min) on the photosynthesis of greenhouse-grown tomato plants during the fruiting/ripening stage. After 30 d of daily irradiation, UV-B and UV-A differently interfered with the photosynthesis. UV-B induced few leaf-necrotic spots, and effects are more evidenced in the stimulation of photosynthetic/protective pigments, meaning a structural effect at the Light-Harvesting Complex. UV-A stimulated flowering/fruiting, paralleled with no visible leaf damages, and the impact on photosynthesis was mostly related to functional changes, in a dose-dependent manner. Both UV-A doses decreased the maximum quantum efficiency of photosystem II (Fv/Fm), the effective efficiency of photosystem II (ΦPSII), and gas exchange processes, including net carbon assimilation (PN). Transcripts related to Photosystem II (PSII) and RuBisCO were highly stimulated by UV supplementation (mostly UV-A), but the maintenance of the RuBisCO protein levels indicates that some protein is also degraded. Our data suggest that plants supplemented with UV-A activate adaptative mechanisms (including increased transcription of PSII peptides and RuBisCO), and any negative impacts on photosynthesis do not compromise the final carbohydrate balances and plant yield, thus becoming a profitable tool to improve precision agriculture.

SELECTION OF CITATIONS
SEARCH DETAIL
...