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Freshwater ecosystems face a particularly high risk of biodiversity loss compared to marine and terrestrial systems. The use of pesticides in agricultural fields is recognized as a relevant stressor for freshwater environments, exerting a negative impact worldwide on the overall status and health of the freshwater communities. In the present work, part of the Horizon 2020 funded SPRINT project, the occurrence of 193 pesticide residues was investigated in 64 small water bodies of distinct typology (creeks, streams, channels, ditches, rivers, lakes, ponds and reservoirs), located in regions with high agricultural activity in 10 European countries and in Argentina. Mixtures of pesticide residues were detected in all water bodies (20, median; 8-40 min-max). Total pesticide levels found ranged between 6.89 and 5860 ng/L, highlighting herbicides as the dominant type of pesticides. Glyphosate was the compound with the highest median concentration followed by 2,4-D and MCPA, and in a lower degree by dimethomorph, fluopicolide, prothioconazole and metolachlor(-S). Argentina was the site with the highest total pesticide concentration in water bodies followed by The Netherlands, Portugal and France. One or more pesticides exceeded the threshold values established in the European Water Framework Directive for surface water in 9 out of 11 case study sites (CSS), and the total pesticide concentration surpassed the reference value of 500 ng/L in 8 CSS. Although only 5 % (bifenthrin, dieldrin, fipronil sulfone, permethrin, and terbutryn) of the individual pesticides denoted high risk (RQ > 1), the ratios estimated for pesticide mixtures suggested potential environmental risk in the aquatic compartment studied.
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Resíduos de Praguicidas , Praguicidas , Poluentes Químicos da Água , Água , Ecossistema , Argentina , Poluentes Químicos da Água/análise , Monitoramento Ambiental , Praguicidas/análise , Rios/químicaRESUMO
This is the first report of Antiteuchus tripterus (Fabricius, 1787) (Heteroptera: Pentatomidae) damaging Araucaria angustifolia (Bertol.) Kuntze, 1898 (Pinales: Araucariaceae) plants in Brazil. This bug, native to the neotropical region, damaged this plant on fragments of mixed rain forest in Bueno Brandão, Minas Gerais state, Brazil. Araucaria angustifolia, native and with ecological and economic values, was widely used in the lumber market and, therefore, threatened with extinction. Nymphs and adults of A. tripterus were observed in March and April with a population reduction until June 2022. The bioecology and damage caused by A. tripterus on A. angustifolia are not known.
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Araucaria , Heterópteros , Animais , Brasil , Ninfa , Dinâmica PopulacionalRESUMO
Sudden Death Syndrome (SDS) caused by Fusarium tucumaniae is a significant threat to soybean production in Argentina. This study assessed the susceptibility of SY 3 × 7 and SPS 4 × 4 soybeans cultivars to F. tucumaniae and studied changes in root isoflavone levels after infection. Additionally, the biocontrol potential of plant-growth promoting rhizobacteria (PGPR) against SDS was also examined. Our results demonstrated that the SY 3 × 7 cultivar exhibited higher disease severity and total fresh weight loss than SPS 4 × 4. Both cultivars showed induction of daidzein, glycitein, and genistein in response to infection, with the partially resistant cultivar displaying significantly higher daidzein levels than the susceptible cultivar at 14 days post infection (dpi) (2.74 vs 2.17-fold), declining to a lesser extent at 23 dpi (0.94 vs 0.35-fold, respectively). However, daidzein was not able to inhibit F. tucumaniae growth in in vitro assays probably due to its conversion to an isoflavonoid phytoalexin which would ultimately be an effective fungal inhibitor. Furthermore, the PGPR bacterium Bacillus amyloliquefaciens BNM340 displayed antagonistic activity against F. tucumaniae and reduced SDS symptoms in infected plants. This study sheds light on the varying susceptibility of soybean cultivars to SDS, offers insights into isoflavone responses during infection, and demonstrates the potential of PGPR as a biocontrol strategy for SDS management, providing ways for disease control in soybean production.
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Fusarium , Isoflavonas , Glycine max , Fusarium/fisiologia , Morte Súbita , Argentina , Doenças das Plantas/prevenção & controle , Doenças das Plantas/microbiologiaRESUMO
Pesticides are widely used as plant protection products (PPPs) in farming systems to preserve crops against pests, weeds, and fungal diseases. Indoor dust can act as a chemical repository revealing occurrence of pesticides in the indoor environment at the time of sampling and the (recent) past. This in turn provides information on the exposure of humans to pesticides in their homes. In the present study, part of the Horizon 2020 funded SPRINT project, the presence of 198 pesticide residues was assessed in 128 indoor dust samples from both conventional and organic farmworker households across Europe, and in Argentina. Mixtures of pesticide residues were found in all dust samples (25-121, min-max; 75, median). Concentrations varied in a wide range (<0.01 ng/g-206 µg/g), with glyphosate and its degradation product AMPA, permethrin, cypermethrin and piperonyl butoxide found in highest levels. Regarding the type of pesticides, insecticides showed significantly higher levels than herbicides and fungicides. Indoor dust samples related to organic farms showed a significantly lower number of residues, total and individual concentrations than those related to conventional farms. Some pesticides found in indoor dust were no longer approved ones (29 %), with acute/chronic hazards to human health (32 %) and with environmental toxicity (21 %).
Assuntos
Poluição do Ar em Ambientes Fechados , Resíduos de Praguicidas , Praguicidas , Humanos , Resíduos de Praguicidas/análise , Monitoramento Ambiental , Poeira/análise , Fazendeiros , Argentina , Praguicidas/análise , Europa (Continente) , Poluição do Ar em Ambientes Fechados/análiseRESUMO
Throughout evolution, plants have developed a highly complex defense system against different threats, including phytopathogens. Plant defense depends on constitutive and induced factors combined as defense mechanisms. These mechanisms involve a complex signaling network linking structural and biochemical defense. Antimicrobial and pathogenesis-related (PR) proteins are examples of this mechanism, which can accumulate extra- and intracellular space after infection. However, despite their name, some PR proteins are present at low levels even in healthy plant tissues. When they face a pathogen, these PRs can increase in abundance, acting as the first line of plant defense. Thus, PRs play a key role in early defense events, which can reduce the damage and mortality caused by pathogens. In this context, the present review will discuss defense response proteins, which have been identified as PRs, with enzymatic action, including constitutive enzymes, ß-1,3 glucanase, chitinase, peroxidase and ribonucleases. From the technological perspective, we discuss the advances of the last decade applied to the study of these enzymes, which are important in the early events of higher plant defense against phytopathogens.
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In regulatory risk assessment, surrogate species of fish, aquatic invertebrates, and primary producers are tested to assess toxicity and subsequently the risk of pesticides to freshwater biota. This study evaluates whether the standard, surrogate test species (mostly temperate in latitudinal distribution) used in many parts of the world are suitable surrogates for first-tier risk assessments involving tropical freshwater biota. Data for the toxicity of pesticides to tropical fish, invertebrates, and primary producer species were extracted from the USEPA ECOTOX database and peer-reviewed literature. For each pesticide, the most sensitive regulatory endpoint extracted from the US Environmental Protection Agency (USEPA) and European Food Safety Authority (EFSA) dossiers for freshwater fish, invertebrates, and primary producers was selected. The ratios of the endpoint for tropical species and for the most sensitive regulatory endpoint for the appropriate taxonomic group were determined. A value >1 indicates that the tropical species is less sensitive than the respective standard regulatory species. Tropical fish species were less sensitive than standard fish species in 84% of the comparisons, and in 93.5% of the comparisons, tropical fish were less or similarly sensitive (within a factor of 5). For aquatic invertebrates, 78.1% of the evaluated tropical species were less sensitive than standard species and 93.3% of tropical invertebrates species were less or similarly sensitive. For primary producers, 96% of tropical species were less sensitive than standard test species. Overall, standard species used globally were more sensitive or similarly sensitive compared to tropical species in more than 93% of the cases. In conclusion, the data show that freshwater toxicity data for pesticides from tests using standard test species, tested according to international accepted guidelines, are appropriate for use in first-tier risk assessments for tropical environments. Integr Environ Assess Manag 2023;19:202-212. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
Assuntos
Praguicidas , Poluentes Químicos da Água , Animais , Praguicidas/toxicidade , Poluentes Químicos da Água/toxicidade , Invertebrados , Medição de Risco , Inocuidade dos Alimentos , PeixesRESUMO
The black aphid Aphis craccivora (Koch, 1854) stands out between the bugs considered cowpea pests. The objective of this study was to evaluate the effects of silicon application on the resistance induction of cowpea plants to the black aphid A. craccivora. The experiment was conducted in the Entomology Laboratory of the Phytosanitary sector of the Centro de Ciências Agrárias at the Universidade Federal do Piauí. The effects of the application of silicon on biological aspects were evaluated using a completely randomized design, with four treatments and 40 repetitions, being: silicon in soil (T1), silicon in soil + leaf (T2), silicone leaf (T3), and control (T4). The following biological variables were evaluated: generation period, reproductive period, fecundity, and daily average of nymphs per female. The silicon and lignin contents were also evaluated in the plants. The silicic acid was applied in a 1% solution around the stem of the plants (soil), 15 days after emergence, by diluting 2 g of the product in 200 mL of water. However, the leaf application was carried out with sprayer five days after application in soil. The non-preference of A. craccivora on bean was also evaluated. The evaluations were performed after 24, 48 and 72 hours of infestation by counting nymphs at 24, 48 and 72 hours and adults at each leaf session. The application of silicon promotes the reduction of the production of nymphs, interfering in the biological aspects of A. craccivora, and has potential to be used in a cowpea pest management program in cowpea.
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Afídeos , Praguicidas/análise , Silício/administração & dosagem , Controle de Pragas/métodos , Vigna/parasitologia , Defesa das Plantas contra HerbivoriaRESUMO
In view of the recurrent applications of pesticides in agricultural producing countries, the increased presence of these substances in the environment raise a demand for the evaluation of adverse effects on non-target organisms. This study assesses the impact of exposure to five pesticides suspected of being endocrine disruptors (atrazine, 2,4-dichlorophenoxyacetic acid, mancozeb, chlorpyrifos and cypermethrin) on the reproductive development of the nematode Caenorhabditis elegans. To this end, nematodes in the L4 larval stage were exposed to different concentrations of pesticides for 24 h and the consequences on brood size, percentage of gravid nematodes, expression of reproductive-related genes and vitellogenin trafficking and endocytosis were measured. Moreover, 17ß-estradiol was used as an estrogenic control for endocrine disrupting compounds throughout the work. The results showed that all the pesticides disturbed to some extent one or more of the evaluated endpoints. Remarkably, we found that atrazine, 2,4-dichlorophenoxyacetic acid and chlorpyrifos produced comparable responses to 17ß-estradiol suggesting that these pesticides may have estrogen-like endocrine disrupting activity. Atrazine and 17ß-estradiol, as well as 2,4-dichlorophenoxyacetic acid and chlorpyrifos to a lesser extent, decreased the brood size, affected vitellogenin trafficking and endocytosis, and changed the expression of several reproductive-related genes. Conversely, mancozeb and cypermethrin had the least impact on the evaluated endpoint. Cypermethrin affected the brood size at the highest concentration tested and mancozeb altered the distribution of vitellogenin only in approximately 10% of the population. However, both products overexpressed hus-1 and vit-2 genes, indicating that an induction of stress could interfere with the normal development of the nematode. In conclusion, our work proved that C. elegans is a useful biological model to identify the effects of estrogen-like endocrine disruptor compounds, and the sublethal endpoints proposed may serve as an important contribution on evaluating environmental pollutants.
Assuntos
Atrazina , Clorpirifos , Disruptores Endócrinos , Herbicidas , Praguicidas , Ácido 2,4-Diclorofenoxiacético , Animais , Atrazina/toxicidade , Caenorhabditis elegans/metabolismo , Clorpirifos/toxicidade , Disruptores Endócrinos/toxicidade , Estradiol/farmacologia , Estrogênios/farmacologia , Herbicidas/toxicidade , Praguicidas/toxicidade , Vitelogeninas/genética , Vitelogeninas/metabolismo , Vitelogeninas/farmacologiaRESUMO
Beneficial soil microorganisms can contribute to biocontrol of plant pests and diseases, induce systemic resistance (ISR) against attackers, and enhance crop yield. Using organic soil amendments has been suggested to stimulate the abundance and/or activity of beneficial indigenous microbes in the soil. Residual streams from insect farming (frass and exuviae) contain chitin and other compounds that may stimulate beneficial soil microbes that have ISR and biocontrol activity. Additionally, changes in plant phenotype that are induced by beneficial microorganisms may directly influence plant-pollinator interactions, thus affecting plant reproduction. We explore the potential of insect residual streams derived from the production of insects as food and feed to promote plant growth and health, as well as their potential benefits for sustainable agriculture.
Assuntos
Insetos , Desenvolvimento Vegetal , Animais , Plantas , Solo , Microbiologia do SoloRESUMO
The lupin (Lupinus mutabilis Sweet) is a legume domesticated and cultivated for more than 4000 years by the pre-Hispanic cultures of the Andean zone. Due to its good taste and protein content, the lupin seed contributes significantly to the food and nutritional security of the Andean population. However, lupin is susceptible to diseases, and of these, anthracnose is the most devastating as it affects the whole crop, including leaves, stems, pods, and seeds. This review focuses on available strategies for management of lupin anthracnose from sowing to harvest. Seed disinfection is the primary anthracnose management strategy. Seed treatment with fungicides reduces transmission from seed to seedling, but it does not eradicate anthracnose. Attention is given to alternative strategies to limit this seed-borne pathogen as well as to enhance plant resistance and to promote plant growth. For anthracnose management in the field, integrated practices are discussed that encompass control of volunteer plants, lupin ontogenetic resistance, and rotation of biocontrol with chemical fungicides at susceptible phenological stages. This review covers some local experiences on various aspects of anthracnose management that could prove useful to other the groups focusing on the problem.
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Cenopalpus wainsteini (Livshitz and Mitrofanov, Proceedings Nikitsky Botanic Garden 39:1-72, 1967), a mite species in the family Tenuipalpidae, was discovered on Pinus sylvestris Thumb. in Lima, Peru, and represents the first record of this species in the Americas. Previously, only Cenopalpus pulcher (Canestrini and Fanzago Acari Academia Cientifico Veneto 5:130-142, 1876) and C. officinalis (Papaioannou-Souliotis, Annals Institut Phytopathology Benaki 15:11-27, 1986) have been reported from the Nearctic and Neotropic regions. The current paper describes and illustrates the morphological characters of female, deutonymph, protonymph and includes the first description of the larval stage of the species. Species of C. wainsteini collected in Peru were compared with specimens collected in Italy, as well as with the original description by Livschitz and Mitrofanov of specimens from Ukraine and the re-description of the species by Arabuli and Kvavadze Int J Acarology 39(7): 538-541 (2013) based on specimens collected in Georgia. Furthermore, notes on Cenopalpus lineola (Canestrini and Fanzago 1876) are included since it is frequently associated with C. wainsteini. Severe damage symptoms caused by this flat mite on its host plants were observed and are discussed herein.
Assuntos
Ácaros , Animais , Itália , Larva , Peru , PlantasRESUMO
The present study aimed to evaluate the effect of applying different concentrations of niacin, at different times in relation to nitrogen fertilization, on the characteristics of Urochloa brizantha. The treatments consisted of applying three concentrations of niacin (0, 100, and 200 mg L-1) and three different moments (two days before, together, and two days after nitrogen fertilization). It was found that there was variation in response, mainly concerning the moment of application of the vitamins, in which the joint and subsequent application of fertilization generally exceeded the application performed previously, and of both concentrations used (100 and 200 mg L-1), in relation to the control without vitamin application. In this way, the application of niacin at a concentration of 100 mg L-1, carried out jointly or after nitrogen fertilization, provides better conditions for developing and producing dry matter of Urochloa brizantha due to the presence of nitrogen.
O presente estudo teve como objetivo avaliar o efeito da aplicação de diferentes concentrações de niacina, em momentos distintos em relação à adubação nitrogenada, sobre as características de Urochloa brizantha. Os tratamentos foram compostos pela aplicação de três concentrações de niacina (0, 100 e 200 mg L-1) e três momentos distintos (dois dias antes, juntamente e dois dias após a adubação nitrogenada). Verificou-se que houve variação de resposta, principalmente em relação ao momento de aplicação das vitaminas, em que as aplicações conjunta e posterior à adubação superaram, de maneira geral, a aplicação realizada anteriormente, e de ambas as concentrações utilizadas (100 e 200 mg L-1), em relação ao controle sem vitamina. Desta maneira, a aplicação de niacina em concentração de 100 mg L-1, realizada de maneira conjunta ou posterior à adubação nitrogenada, propicia melhores condições para o desenvolvimento e a produção de matéria seca de Urochloa brizantha, devido à presença do nitrogênio.
Assuntos
Poaceae/química , Niacina/administração & dosagem , Nitrogênio/administração & dosagem , Niacinamida/administração & dosagem , FertilizantesRESUMO
In the last century, biological invasions have increased greatly due to the intensification in international trade and world climate change, thus representing one of the most relevant issues for agricultural productivity and biodiversity. The Animal and Plant Health Inspection Service of the United States, from 2019 to 2021, intercepted different species from Italy belonging to the Orders Ixodida, Sarcoptiformes and Trombidiformes. The study reported four new records and several new host plant associations. In this framework, the inspection system not only plays a relevant role in the plant protection, human and animal health, but also contributes to the knowledge of the Acari fauna from exporting countries.
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The essential oil (EO), the methanolic (MeOH), and the 70% ethanolic (70% EtOH) extracts obtained from the aerial parts of Ocimum campechianum Mill. (Ecuador) were chemically characterized through gas-chromatography coupled to mass spectrometry detector (GC-MS), high-performance liquid chromatography coupled to diode array-mass spectrometry detectors (HPLC-DAD-MS) and studied for their in vitro biological activity. The radical scavenger activity, performed by spectrophotometric 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, highlighted significant IC50 values for the EO, extracts and their main constituents (eugenol and rosmarinic acid). EO (and eugenol) showed noteworthy activity against Pseudomonas syringae pv. syringae and a moderate effect against clinical Candida strains, with possible synergism in association to fluconazole against the latter microorganisms. The extracts and pure molecules exhibited weak cytotoxic activity against the HaCat cell line and no mutagenicity against Salmonella typhimurium TA98 and TA100 strains, giving indication of safety. Instead, EO showed a weak activity against adenocarcinomic human alveolar basal epithelial cells (A549). The above-mentioned evidence leads us to suggest a potential use of the crude drug, extracts, and EO in cosmetic formulation and food supplements as antioxidant agents. In addition, EO may also have a possible application in plant protection and anti-Candida formulations.
Assuntos
Cinamatos/farmacologia , Depsídeos/farmacologia , Eugenol/farmacologia , Ocimum/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Células A549 , Antibacterianos/farmacologia , Antioxidantes/farmacologia , Benzotiazóis/química , Compostos de Bifenilo/química , Candida/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sinergismo Farmacológico , Equador , Fluconazol/farmacologia , Humanos , Concentração Inibidora 50 , Testes de Sensibilidade Microbiana , Mutagênese , Óleos Voláteis/análise , Picratos/química , Ácidos Sulfônicos/química , Ácido RosmarínicoRESUMO
Plants are phytochemical hubs containing antioxidants, essential for normal plant functioning and adaptation to environmental cues and delivering beneficial properties for human health. Therefore, knowledge on the antioxidant potential of different plant species and their nutraceutical and pharmaceutical properties is of utmost importance. Exploring this scientific research field provides fundamental clues on (1) plant stress responses and their adaptive evolution to harsh environmental conditions and (2) (new) natural antioxidants with a functional versatility to prevent and treat human pathologies. These natural antioxidants can be valorized via plant-derived foods and products. Cuba contains an enormously rich plant biodiversity harboring a great antioxidant potential. Besides opening new avenues for the implementation of sustainable agroecological practices in crop production, it will also contribute to new strategies to preserve plant biodiversity and simultaneously improve nature management policies in Cuba. This review provides an overview on the beneficial properties of antioxidants for plant protection and human health and is directed to the valorization of these plant antioxidants, emphasizing the need for biodiversity conservation.
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Pesticides are not only used on food but also on non-food crops, such as tobacco, to control a range of unwanted animal, plant, and microbial, fungal pests. The residue levels in tobacco leaves are expected to decline up to harvest, during drying, and when the leaves are further processed. Additional pesticides may also be applied to the finished product and residue levels may remain present even when the tobacco is burned. Human exposure to pesticide residues on tobacco occurs when residues remaining in cigarette smoke are inhaled. Based on this assumption, the objectives of this research were (i) to determine the level of pesticides residues in harvested tobacco leaves and (ii) to assess the risk of human exposure to these residues in tobacco smoke. Pesticide residues were detected in all analysed tobacco samples. These detected residues represent ten different active ingredients (AI), three of these AIs (thiodicarb, alachlor, and endosulfan) are no longer allowed in Europe. A 54.7% of these residues were quantifiable. Furthermore, it was found that with the use of solid-phase extraction sorbent (SPE) as adsorbent and n-hexane as solvent, higher recoveries of the pesticide residues in the tobacco smoke from the amount spiked can be obtained. It was also found that cigarette filters help to reduce the intake of residues of pesticides that may be present in cigarettes. Finally, the study concluded that both active smoking and passive smoking populations are exposed to pesticide residues in the tobacco smoke.
Assuntos
Resíduos de Praguicidas/análise , Praguicidas/análise , Poluição por Fumaça de Tabaco , Monitoramento Ambiental , Europa (Continente) , Humanos , Medição de Risco , Fumaça/análise , NicotianaRESUMO
Endocrine disrupting pesticides (EDPs) are exogenous compounds that disrupt endocrine activity. Human exposure to EDPs can occur through occupational contact, and through the consumption of food, milk and water with trace amounts of these pollutants. Several EDPs are epidemiologically linked to breast cancer or are considered as possible carcinogens. However, current evidence is not fully conclusive and their mechanisms of action remain unknown. Thus, the potential interactions between 262 EDPs and 189 proteins associated with breast cancer were evaluated by using a virtual high-throughput screening approach, with AutoDock Vina 1.1.1. The molecular coordinates were previously downloaded from Protein Data Bank and EDCs DataBank, and used for preparation and optimization in Sybyl X-2.0. The best affinity score (-11.0 kcal/mol) was obtained for flucythrinate with the nuclear receptor for vitamin D (VDR). This synthetic pyrethroid, along with other EDPs, such as fluvalinate, bifenthrin, cyhalothrin and cypermethrin, are proposed as multi-target ligands of several proteins related to breast cancer. In addition, the validation of our protocol showed a good accuracy in terms of binding pose prediction and affinity estimation. This study provides a guide to prioritize EDPs for which further in vitro and in vivo analysis could be done to evaluate the risk and possible mechanisms of action of these contaminants and their potential association with breast cancer.
Assuntos
Neoplasias da Mama/metabolismo , Disruptores Endócrinos/química , Disruptores Endócrinos/toxicidade , Proteínas de Neoplasias/efeitos dos fármacos , Praguicidas/química , Praguicidas/toxicidade , Feminino , Ensaios de Triagem em Larga Escala , Humanos , Modelos Moleculares , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Ligação Proteica , Reprodutibilidade dos Testes , Relação Estrutura-AtividadeRESUMO
A ocorrência de déficit hídrico durante o ciclo produtivo do arroz de terras altas, pode resultar em menor desenvolvimento vegetativo e produção. Neste sentido, verifica-se a possibilidade da utilização de produtos com efeito protetivo, tal como a vitamina B1. O objetivo deste trabalho foi avaliar os efeitos da aplicação exógena de tiamina, via foliar, durante e 30 dias após a emergência das plantas, sobre as características biométricas e produtivas de arroz de terras altas submetido a intervalo com déficit hídrico. O experimento foi delineado em blocos casualizados, com cinco tratamentos em cinco repetições, totalizando 25 parcelas experimentais. Os tratamentos foram assim definidos: T1 controle sem aplicação da vitamina; T2 aplicação de 50 mg L-1 de tiamina na emergência das plântulas; T3 aplicação de 50 mg L-1 de tiamina aos 30 dias após a emergência; T4 aplicação de 100 mg L-1 de tiamina na emergência das plântulas; T5 aplicação de 100 mg L-1 de tiamina aos 30 dias após a emergência. O estresse hídrico foi aplicado quando as plantas estavam em estádio variando de V3 a V6. Foram avaliados os teores relativos de clorofilas a, b e total, a altura de planta, o número de perfilhos, o comprimento e número de panículas por metro quadrado, a massa de 1000 grãos, a fertilidade de espiguetas e a produtividade. Destacou-se a aplicação da tiamina aos 30 dias após...
The occurrence of water deficit during the upland rice production cycle may result in lower vegetative development and yield. In this sense, it is possible to use products with a protective effect, such as vitamin B1. The objective of this work was to assess the effects of exogenous thiamine application, on leaves, during and 30 days after plant emergence, on the biometric and productive characteristics of upland rice submitted to an interval with water deficit. The experiment was designed in randomized blocks with five treatments. The treatments were defined as follows: T1 - control without vitamin application; T2 - application of 50 mg L-1 thiamine in seedling emergence; T3 - application of 50 mg L-1 thiamine 30 days after emergence; T4 - application of 100 mg L-1 thiamine in seedling emergence; T5 - application of 100 mg L-1 thiamine 30 days after emergence. Water stress was applied when the plants were at a stage ranging from V3 to V6. Relative levels of chlorophylls a, b, and total, plant height, number of tillers, length, and number of panicles per square meter, 1000 grains weight, spikelet fertility, and yield were assessed. Thiamine application was highlighted 30 days after emergence, increasing panicle length, 1000 grains weight, and spikelet fertility by 16.4%, 8.4%, and 6.0%, respectively. The application of thiamine as a foliar treatment mitigates the effects...
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Desidratação , Oryza/crescimento & desenvolvimento , Oryza/efeitos dos fármacos , Reguladores de Crescimento de Plantas , Tiamina/administração & dosagemRESUMO
A ocorrência de déficit hídrico durante o ciclo produtivo do arroz de terras altas, pode resultar em menor desenvolvimento vegetativo e produção. Neste sentido, verifica-se a possibilidade da utilização de produtos com efeito protetivo, tal como a vitamina B1. O objetivo deste trabalho foi avaliar os efeitos da aplicação exógena de tiamina, via foliar, durante e 30 dias após a emergência das plantas, sobre as características biométricas e produtivas de arroz de terras altas submetido a intervalo com déficit hídrico. O experimento foi delineado em blocos casualizados, com cinco tratamentos em cinco repetições, totalizando 25 parcelas experimentais. Os tratamentos foram assim definidos: T1 controle sem aplicação da vitamina; T2 aplicação de 50 mg L-1 de tiamina na emergência das plântulas; T3 aplicação de 50 mg L-1 de tiamina aos 30 dias após a emergência; T4 aplicação de 100 mg L-1 de tiamina na emergência das plântulas; T5 aplicação de 100 mg L-1 de tiamina aos 30 dias após a emergência. O estresse hídrico foi aplicado quando as plantas estavam em estádio variando de V3 a V6. Foram avaliados os teores relativos de clorofilas a, b e total, a altura de planta, o número de perfilhos, o comprimento e número de panículas por metro quadrado, a massa de 1000 grãos, a fertilidade de espiguetas e a produtividade. Destacou-se a aplicação da tiamina aos 30 dias após...(AU)
The occurrence of water deficit during the upland rice production cycle may result in lower vegetative development and yield. In this sense, it is possible to use products with a protective effect, such as vitamin B1. The objective of this work was to assess the effects of exogenous thiamine application, on leaves, during and 30 days after plant emergence, on the biometric and productive characteristics of upland rice submitted to an interval with water deficit. The experiment was designed in randomized blocks with five treatments. The treatments were defined as follows: T1 - control without vitamin application; T2 - application of 50 mg L-1 thiamine in seedling emergence; T3 - application of 50 mg L-1 thiamine 30 days after emergence; T4 - application of 100 mg L-1 thiamine in seedling emergence; T5 - application of 100 mg L-1 thiamine 30 days after emergence. Water stress was applied when the plants were at a stage ranging from V3 to V6. Relative levels of chlorophylls a, b, and total, plant height, number of tillers, length, and number of panicles per square meter, 1000 grains weight, spikelet fertility, and yield were assessed. Thiamine application was highlighted 30 days after emergence, increasing panicle length, 1000 grains weight, and spikelet fertility by 16.4%, 8.4%, and 6.0%, respectively. The application of thiamine as a foliar treatment mitigates the effects...(AU)
Assuntos
Tiamina/administração & dosagem , Oryza/efeitos dos fármacos , Oryza/crescimento & desenvolvimento , Desidratação , Reguladores de Crescimento de PlantasRESUMO
Arbuscular mycorrhizal fungi (AMF) are mutualistic symbionts considered a key group in soil systems involved in the provision of several ecosystem services. Recently they have been listed by EFSA as organisms to be included in the test battery for the risk assessment of plant protection product (PPPs). This study aimed to contribute to improve the ISO Protocol (ISO 10832: 2009) by assessing the feasibility of using other AMF species under different test conditions. Overall, results showed that AMF species Gigaspora albida and Rhizophagus clarus (selected out of five AMF species) are suitable to be used in spore germination tests using the ISO protocol (14 days incubation with sand or artificial soil as substrate) to test PPPs. However, several modifications to the protocol were made in order to accommodate the use of the tested isolates, namely the incubation temperature (28 °C instead of 24 °C) and the change of reference substance (boric acid instead of cadmium nitrate). The need for these changes, plus the results obtained with the three fungicides tested (chlorothalonil, mancozeb and metalaxyl-M) and comparisons made with literature on the relevance of the origin of AMF isolates in dictating the adequate test conditions, emphasize the importance of adjusting test conditions (AMF species/isolates and test temperature) when assessing effects for prospective risk assessment targeting different climatic zones. So, further studies should be conducted with different AMF species and isolates from different climatic regions, in order to better define which species/isolate and test conditions should be used to assess effects of a particular PPP targeting a given climatic zone.