Navegando por Autor "Debona, Daniel"
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Item Alterações bioquímicas e fisiológicas em plantas de trigo infectadas por Pyricularia oryzae(Universidade Federal de Viçosa, 2012-02-14) Debona, Daniel; Rodrigues, Fabrício de ávila; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4709080E6; http://lattes.cnpq.br/2077755323901652; Damatta, Fábio Murilo; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4784185Y9; Cunha, Luis Claudio Vieira da; http://lattes.cnpq.br/9367947173322278A brusone, causada pelo fungo Pyricularia oryzae, constitui a doença mais importante da cultura do trigo no cerrado brasileiro. No entanto, informações na literatura da interação trigo-P. oryzae ainda são limitadas. Neste estudo foram investigadas as alterações bioquímicas e fisiológicas em plantas de trigo das cultivares BR 18 e BRS 229, suscetível e parcialmente resistente à brusone no estádio de planta jovem, respectivamente, durante o processo infeccioso de P. oryzae. As variáveis estudadas foram a severidade da brusone, a atividade de enzimas do sistema antioxidativo, as concentrações de superóxido (O2-), peróxido de hidrogênio (H2O2) e aldeído malônico (MDA), e o extravasamento de eletrólitos (EE), bem como os parâmetros de trocas gasosas às 48, 72 e 96 horas após a inoculação (hai) com P. oryzae. Adicionalmente, foram determinadas a taxa máxima de carboxilação (Vcmax), a taxa máxima de transporte de elétrons usados na regeneração da ribulose-1,5-bisfosfato (RUBP) (Jmax), a respiração (Rd) e calculada a relação Jmax/Vcmax com base na resposta da taxa líquida de assimilação de CO2 (A) a diferentes concentrações internas de CO2 (Ci) (curva A/Ci). A severidade da brusone foi menor nas plantas da cultivar BRS 229 do que nas plantas da cultivar BR 18. A atividade das enzimas do sistema antioxidativo foi fortemente afetada pela infecção por P. oryzae e usualmente maior nas plantas inoculadas do que nas plantas não inoculadas. O aumento na atividade das enzimas superóxido dismutase, peroxidase, peroxidase do ascorbato e glutationa- S-transferase às 96 hai foi mais pronunciado para a cultivar BRS 229 do que para a cultivar BR 18. A atividade da redutase da glutationa (GR) e catalase (CAT) aumentou somente nas plantas inoculadas da cultivar BRS 229 às 96 hai em relação às plantas não inoculadas. Para a cultivar BR 18, a atividade da GR não foi afetada pela inoculação com P. oryzae e a atividade da CAT foi menor nas plantas inoculadas do que nas não inoculadas. A atividade da peroxidase da glutationa aumentou nas plantas inoculadas da cultivar BR 18 em relação às plantas não inoculadas às 48 e 72 hai, e não foi afetada pela inoculação com P. oryzae nas plantas da cultivar BRS 229. A concentração de O2- aumentou em 153viii e 72% às 96 hai nas plantas inoculadas das cultivares BR 18 e BRS 229, respectivamente, comparadas com as plantas não inoculadas. A concentração de H2O2 foi 59% maior nas plantas inoculadas da cultivar BR 18 em relação às plantas não inoculadas às 96 hai, porém não houve diferença entre plantas inoculadas e não inoculadas na concentração de H2O2 para a cultivar BRS 229. A concentração de MDA foi maior nas plantas inoculadas às 48, 72, e 96 hai para a cultivar BR 18 e somente às 48 hai para a cultivar BRS 229, em relação às plantas não inoculadas. O EE aumentou em 323 e 188% às 96 hai nas plantas inoculadas das cultivares BR 18 e BRS 229, respectivamente, comparadas com as plantas não inoculadas. Os parâmetros de trocas gasosas A, condutância estomática e taxa de transpiração, bem como Vcmax e Jmax foram significativamente reduzidos nas plantas de trigo inoculadas das duas cultivares em relação às plantas não inoculadas. Essa redução, no entanto, foi menos pronunciada nas plantas da cultivar BRS 229 do que nas plantas da cultivar BR 18, o que esteve associado com a menor severidade da brusone observada para a cultivar BRS 229. Ci aumentou em 32 e 14% às 96 hai nas plantas inoculadas das cultivares BR 18 e BRS 229, respectivamente. A relação Jmax/Vcmax aumentou nas plantas inoculadas das duas cultivares em relação às plantas não inoculadas. Rd aumentou 208% nas plantas inoculadas da cultivar BR 18 em relação às plantas não inoculadas às 96 hai, porém não houve diferença em Rd entre plantas inoculadas e não inoculadas para a cultivar BRS 229. Os resultados do presente estudo demonstraram a importância de um sistema antioxidativo eficiente para remover o excesso de espécies reativas de oxigênio gerado durante a infecção de plantas de trigo por P. oryzae, limitando o dano celular causado pelo fungo. Adicionalmente, esse sistema antioxidativo mais eficiente parece contribuir para uma maior resistência do trigo à brusone. As avaliações fisiológicas demonstraram que a fotossíntese de plantas de trigo foi significativamente reduzida pela infecção por P. oryzae, a qual esteve associada principalmente à menor atividade aparente da Rubisco, seguido pela menor regeneração de RuBP. O conhecimento das alterações bioquímicas e fisiológicas de plantas de trigo infectadas por P. oryzae é de suma importância para o desenvolvimento de estratégias de controle eficientes da brusone.Item Avaliação da ativação de defesa em soja contra Phakopsora pachyrhizi em condições controladas(Ciência e Agrotecnologia, 2010-07) Debona, Daniel; Meneghetti, Rosana Ceolin; Balardin, Ricardo Silveiro; Corte, Gerson Dalla; Favera, Diego DallaA efetividade da ativação de defesa em diferentes cultivares de soja contra Phakopsora pachyrhizi proporcionada pelo fosfito, bem como sua associação com fungicidas aplicados em diferentes épocas em relação à inoculação com o patógeno, foi estudada em condições de casa-de-vegetação em dois ensaios conduzidos no delineamento inteiramente casualizado, com quatro repetições. Os resultados obtidos indicaram que o fosfito não foi capaz de induzir a expressão dos mecansimos de defesa, uma vez que não foi observada qualquer redução na severidade, número de pústulas.cm-2, e na Área Abaixo da Curva de Progresso de Doença (AACPD), por conta da aplicação do produto. O progresso da ferrugem foi mais lento na cultivar Fundacep 55 RR, que teve uma AACPD 53% menor do que a cultivar Fundacep 56 RR, a mais suscetível. O fungicida epoxiconazol + piraclostrobina proporcionou uma redução na AACPD de 29%, quando comparado ao emprego do triazol isolado na média das épocas de aplicação. As aplicações mais próximas da inoculação e preventivas foram mais efetivas do que aquelas realizadas de forma muito precoce ou muito tardia em relação à infecção das plantas pelo patógeno. Os resultados indicaram que o fosfito não induziu resistência em soja contra P. pachyrhizi, e que houve variação na resistência parcial à ferrugem por parte das cultivares e na efetividade dos fungicidas entre si e quanto ao momento em que os mesmos são aplicados.Item Changes in leaf gas exchange and chlorophyll a fluorescence on soybean plants supplied with silicon and infected by Cercospora sojina(Journal of Phytopathology, 2018-12) Nascimento, Kelly Juliane Telles; Debona, Daniel; Rezende, Danielle; DaMatta, Fábio Murilo; Rodrigues, Fabrício ÁvilaFrogeye spot, caused by Cercospora sojina, is one of the major diseases causing yield losses in soybean. Considering the potential of silicon (Si) to attenuate the physiological impairments imposed by pathogens infection, this study investigated its effect on leaf gas exchange and chlorophyll (Chl) a fluorescence parameters as well as on the concentrations of photosynthetic pigments and carbohydrate pools on soybean plants from cultivars Bossier and Conquista (susceptible and resistant to frogeye spot, respectively) grown in hydroponic culture containing 0 or 2 mM Si (−Si and +Si plants, respectively) that were noninoculated or inoculated with C. sojina. Plants from cultivar Bossier were more susceptible to frogeye spot compared to cultivar Conquista regardless of Si supply. Frogeye spot severity increased by Si supply regardless of the cultivar. There were no changes in the physiological parameters for noninoculated +Si plants. Even though the susceptibility of plants from cultivar Bossier to frogeye spot increased by Si supply, they showed lower values for the leaf gas exchange parameters, photochemical efficiency and concentration of photosynthetic pigments. The impairments imposed by C. sojina infection on the physiology of plants from cultivar Conquista were governed chiefly by reductions in stomatal conductance regardless of Si supply. The increase in hexose concentration for inoculated plants of the two cultivars was associated with their resistance to frogeye spot. Considering that the increased susceptibility of +Si plants from cultivar Conquista did not result in physiological impairments, it is plausible to rule out that the lower photosynthetic efficiency of plants from cultivar Bossier occurred due to a sharp reduction in the photosynthetically active leaf tissue.Item Changes in the antioxidant system in soybean leaves infected by Corynespora cassiicola(Phytopathology, 2015-02-25) Fortunato, Alessandro Antônio; Debona, Daniel; Bernardeli, Arthur Martins Almeida; Rodrigues, Fabrício ÁvilaConsidering the importance of target spot, caused by the fungus Corynespora cassiicola, to reduce soybean yield in Brazil and that more basic information regarding the soybean−C. cassiicola interaction is needed, the present study aimed to investigate whether the cellular damage caused by C. cassiicola infection could activate the antioxidant system and whether a more efficient antioxidant system could be associated with an increase in soybean resistance to target spot. The activities of the antioxidant enzymes superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, glutathione peroxidase, glutathione reductase, glutathione S-transferase as well as the concentrations of ascorbate (AsA), hydrogen peroxide (H2O2), superoxide (O2•−), and malondialdehyde (MDA) were measured in soybean plants from two cultivars differing in resistance to the pathogen. The number of lesions per square centimeter was significantly reduced by 14% in plants from cultivar Fundacep 59 compared with plants from cultivar TMG 132. The area under the disease progress curve was significantly lower, by 15%, in plants from Fundacep 59 than in plants from TMG 132. Generally, antioxidant enzyme activities and AsA concentration significantly increased in response to C. cassiicola infection in plants from both cultivars, however more prominent increases were recorded for plants from Fundacep 59. The concentrations of MDA, H2O2, and O2•− also increased, particularly for plants from TMG 132. The results from this study highlight the importance of a more efficient antioxidative system in the removal of reactive oxygen species generated in soybean plants during C. cassiicola infection, contributing to the resistance to target spot.Item Chlorophyll a fluorescence imaging of soya bean leaflets infected by Corynespora cassiicola(Journal of Phytopathology, 2018-12) Fortunato, Alessandro A.; Debona, Daniel; Aucique‐Pérez, Carlos E.; Corrêa, Emerson Fialho; Rodrigues, Fabrício A.Considering the importance of target spot, caused by Corynespora cassiicola, to impact soya bean yield, this study investigated the C. cassiicola‐induced perturbations in the photosynthesis of soya bean plants from cultivars Fundacep 59 (moderately resistant) and TMG 132 (susceptible) by examining the chlorophyll (Chl) a fluorescence parameters and imaging and the photosynthetic pigment pools. The area under disease progress curve decreased by 38% for plants from cultivar Fundacep 59 in comparison with plants from cultivar TMG 132. The concentration of total Chla+b significantly increased by 16% and the Chla+b/carotenoids ratio significantly decreased by 11% for plants from cultivar Fundacep 59 in comparison with plants from cultivar TMG 132. Significant decreases of 31% and 8%, respectively, for the concentration of Chla+b and the Chla+b/carotenoids ratio occurred for inoculated plants in comparison with noninoculated ones regardless of the cultivar. As target spot developed, the values of maximal photosystem II quantum yield (Fv/Fm), effective photosystem II quantum yield [Y(II)], quantum yield of regulated energy dissipation [Y(NPQ)] and quantum yield of nonregulated energy dissipation [Y(NO)] increased, especially for plants from cultivar TMG 132. There were positive correlations of area under disease progress curve (AUDPC) with both Y(NPQ) and Y(NO) regardless of the cultivar. For cultivar TMG 132, the correlation between AUDPC and the electron transport rate was negative. Based on the analysis of the Chl a fluorescence, it was possible to elucidate the enormous potential of target spot to impair the functionality on the photosynthetic apparatus that may help the plants to invest in metabolic pathways involved in host defence responses.Item Defence‐related enzymes in soybean resistance to target spot(Journal Phytopathology, 2015-09) Rodrigues, Fabrício A.; Fortunato, Alessandro A.; Debona, Daniel; Bernardeli, Arthur M. A.Target spot, caused by the fungus Corynespora cassiicola, has become a serious foliar disease in soybean production in the Brazilian Cerrado. Information in the literature regarding the biochemical defence responses of soybean to C. cassiicola infection is rare. Therefore, the objective of this study was to determine the biochemical features associated with soybean resistance to target spot. The activities of chitinases (CHI), β‐1‐3‐glucanases (GLU), phenylalanine ammonia‐lyases (PAL), peroxidases (POX), polyphenol oxidases (PPO) and lipoxygenases (LOX), as well as the concentrations of total soluble phenolics (TSP) and lignin‐thioglycolic acid (LTGA) derivatives, were determined in soybean leaves from both a resistant (FUNDACEP 59) and a susceptible (TMG 132) cultivar. The target spot severity, number of lesions per cm2 of leaflet and area under the disease progress curve were significantly lower for plants from cv. FUNDACEP 59 compared to plants from cv. TMG 132. The GLU, CHI, PAL, POX and PPO activities and the concentration of LTGA derivatives increased significantly, whereas LOX activity decreased significantly on the leaves infected by C. cassiicola. Inoculated plants from cv. FUNDACEP 59 showed a higher PPO activity and concentrations of TSP and LTGA derivatives at 4 and 6 days after inoculation compared to plants from cv. TMG 132. In conclusion, the results of this study demonstrated that the defence‐related enzyme activities increased upon C. cassiicola infection, regardless of the basal level of resistance of the cultivar studied. The increases in PPO activity and concentrations of TSP and LTGA derivatives, but lower LOX activity, at early stages of C. cassiicola infection were highly associated with soybean resistance to target spot.Item Induction of resistance to Pyricularia oryzae in wheat by acibenzolar-S-methyl, ethylene and jasmonic acid(Tropical Plant Pathology, 2014-05) Rios, Jonas Alberto; Rodrigues, Fabrício Ávila; Debona, Daniel; Resende, Renata Sousa; Moreira, Wiler Ribas; Andrade, Camila Cristina LageThis study investigated the effects of acibenzolar-S-methyl (ASM), ethylene (ET) and jasmonic acid (JA) on the resistance of two wheat cultivars (BRS-229 and BR-18) to infection by Pyricularia oryzae. The treatments included spraying plants with ASM (300 mg L-1), ET (0.5 mM), JA (0.1 mM) and distilled water (control) 48 h before inoculation with P. oryzae. Malondialdehyde concentration, an indicative of oxidative damage to the lipids in the leaf cells, was significantly higher for plants sprayed with ASM compared to plants sprayed with JA and ET. Plants sprayed with JA and ET showed reduced values for the number of lesions per cm2 of leaf area and area under blast progress curve, but these hormones had no effect on the incubation period and lesion size (in mm). Plants sprayed with JA and ET showed reduce blast symptoms in comparison to plants sprayed with ASM due to greater peroxidase, polyphenoloxidase, chitinase and β-1,3-glucanase activities.Item Microscopic aspects of the colonization of Pyricularia oryzae on the rachis of wheat plants supplied with silicon(Bragantia, 2015-04) Cruz, Maria Fernanda Antunes da; Silva, Larisse Arantes Freitas; Rios, Jonas Alberto; Debona, Daniel; Rodrigues, Fabrício ÁvilaConsidering the importance of blast, caused by Pyricularia oryzae, to reduce wheat yield, this study investigate how silicon (Si) could reduce the wheat blast symptoms in the rachis tissues using light microscopy and scanning electron microscopy. Wheat plants (cv. BR 18) were grown in hydroponic culture with either 0 (–Si) or 2 mM (+Si) of Si. Blast symptoms were very well developed on the spikes of the –Si plants, which showed intense discoloration in contrast with the spikes of the +Si plants. At 72 hours after inoculation (hai), fungal hyphae extensively colonized the epidermis and the collenchyma tissue in the radial direction in the rachis of the –Si plants. In the +Si plants, fungal hyphae colonized the epidermis and the collenchyma cells to a lesser extent than in the –Si plants. At 96 hai, fungal hyphae were observed in the epidermis, vascular bundles and cortical tissue in the rachis node of the -Si plants. In the +Si plants, a phenolic-like material was detected in the parenchyma with lower fungal colonization in comparison with the –Si plants. In scanning electron microscopy, fungal hyphae were scarcely observed in the upper epidermal, collenchyma and parenchyma cells in the rachis tissue of the +Si plants, whereas in the rachis tissue of the –Si plants, fungal hyphae extensively colonized the epidermis, collenchyma, parenchyma and vascular bundles.Item Physiological, biochemical and microscopic aspects of the rice-Bipolaris oryzae interaction mediated by a strobilurin fungicide(Universidade Federal de Viçosa, 2016-02-17) Debona, Daniel; Rodrigues, Fabrício de Ávila; http://lattes.cnpq.br/2077755323901652Strobilurins are among the most important fungicides that are used for plant disease control worldwide. In addition to their fungicide effect, strobilurins can also affect some physiological and biochemical aspects of treated plants. Nonetheless physiological, biochemical and microscopic alterations caused by azoxystrobin (Az), the main marketed strobilurin, in rice crop remain elusive. To address this issue, detailed gas exchange measurements and chlorophyll a fluorescence analysis, antioxidant and defense systems assays as well light microscopy analysis were performed on rice plants (cultivar Metica-1) that were sprayed or non-sprayed with Az (+Fu and -Fu plants) and either challenged or not with Bipolaris oryzae, the causal agent of brown spot. The +Fu non-inoculated plants displayed lower carbon (C) fixation than -Fu plants, and such decrease was not related to photochemical or biochemical limitations but rather to decreased stomatal conductance that limited the CO 2 influx into the mesophyll cells. The photosynthesis of -Fu plants decreased upon B. oryzae infection, which was chiefly governed by photochemical and biochemical limitations. The energy surplus that was caused by limited C fixation in the +Fu inoculated plants was thermally and effectively dissipated until 72 hours after inoculation (hai). For the -Fu plants, however, this mechanism was not sufficient to prevent chronic photoinhibition to photosynthesis. The inoculated plants were not able to fully capture and exploit the collected light energy, but these constraints were greatly limited in the presence of Az. In general, the +Fu plants did not show changes in the activities of antioxidant enzymes, but displayed higher concentrations of reduced glutathione (GSH) than -Fu plants. The activities of superoxide dismutase, peroxidase, ascorbate peroxidase, glutathione peroxidase, glutathione reductase, and glutathione-S-transferase were increased upon B. oryzae infection, but such increases were lower in the +Fu plants. Catalase activity decreased in the inoculated plants compared to the non-inoculated plants regardless of fungicide treatment. The GSH concentration increased in response to the B. oryzae infection, and the +Fu plants sustained higher levels of GSH at advanced stages of fungal infection than did the -Fu plants. The inoculated plants exhibited an extensive oxidative stress as evidenced by higher concentrations of hydrogen peroxide and malondialdehyde compared to the non-inoculated plants, but lower and later increases were recorded in the +Fu plants than in the -Fu plants. The +Fu plants displayed higher activities of β- 1,3-glucanase, peroxidase, polyphenol oxidase (PPO) and lipoxygenase (LOX) in the absence of B. oryzae inoculation and of phenylalanine ammonia lyase, PPO and LOX at 24 hai compared to the -Fu plants. Concentrations of total soluble phenols (TSP) were transiently reduced by fungal infection in the +Fu plants, but such plants presented higher TSP levels at 144 hai relative to their -Fu counterparts. Irrespective of the fungicide treatment, B. oryzae infection increased activities of all defense enzymes studied, but such increases usually were higher for the -Fu plants than for the +Fu plants. Concentrations of lignin thioglycolic acid derivatives were increased following fungal infection in the -Fu plants. Microscopic analyses revealed that hyphae from B. oryzae colonized bulliform, bundle sheath, epidermal, guard, mesophyll and vascular bundle cells besides intercellular spaces, but fewer and smaller fungal cells were noticed in the +Fu than in the -Fu plants. However, the constrained fungal invasion verified in the +Fu plants was not accompanied by amplified defense reactions since cells of the - Fu plants reacted by accumulating phenol-like material, whereas such reaction was only limited in cells of the +Fu plants. Overall, our results showed that Az impaired the photosynthetic performance of non-infected plants by diffusive constraints but prevented, to a greater extent, the damage to the photosynthetic apparatus during the infection process of B. oryzae. In addition, Az reduced B. oryzae-induced oxidative stress by limiting brown spot development rather than by activating the antioxidant system. Although Az had transiently reprogrammed activities of defense enzymes, which may have contributed for explaining the reduced brown spot severity observed in the +Fu plants, its fungicidal activity played a major role in reducing B. oryzae infection.Item A set of standard area diagrams to assess severity of frogeye leaf spot on soybean(European Journal of Plant Pathology, 2015-03-14) Debona, Daniel; Nascimento, Kelly Juliane Telles; Rezende, Danielle; Rios, Jonas Alberto; Bernardeli, Arthur Martins Almeida; Silva, Leandro Castro; Rodrigues, Fabrício ÁvilaA set of standard area diagrams (SADs) was developed and validated to aid visual assessment of severity of frogeye leaf spot (FLS) caused by Cercospora sojina. The SAD has eight color images of diseased leaflets with severity values that ranged from 0.1 to 39.9 %. The SAD was validated by a group of 20 raters [10 experienced (ER) and 10 inexperienced (IR)], who assessed the same set of 50 images twice, the first without SADs and the second using SADs as an aid. The SADs significantly improved accuracy [coefficients of bias (C b ) were 0.64 and 0.99 for IR and 0.98 and 0.99 for ER, without and with SADs, respectively], precision [correlation coefficients (r) were 0.89 and 0.95 for IR and 0.94 and 0.97 for ER, without and with SADs, respectively] and overall agreement [Lin’s concordance correlation coefficients (ρ c ) were 0.57 and 0.94 for IR and 0.92 and 0.97 for ER without and with SADs, respectively]. The estimates of severity of FLS were more reliable when using SADs. Both the inter-rater reliability (coefficient of determination, R:^2 ) and intra-class coefficient (ρ) were significantly increased by using SADs. Therefore, it is believed that the SADs proposed in the present study will be a useful tool to aid accurate, precise and reliable estimates of severity of FLS in experiments (e.g., fungicide screening, assessment of partial resistance of soybean genotypes to FLS) and to aid in decision-making purposes.Item A set of standard area diagrams to assess white mold severity on the leaflets of common beans(Crop Protection, 2018-12) Fagundes-Nacarath, Inaia Rhavene Freire; Debona, Daniel; Novaes, Maria Izabel Costa; Rodrigues, Fabrício ÁvilaThe fungus Sclerotinia sclerotiorum is the major pathogen affecting common beans yield worldwide and an adequate disease quantification is demanded in some trials. However, a set of standard area diagrams (SADs) to aid visual assessment of severity of white mold (SWM) is lacking. This study developed SADs consisting of eight color images of diseased leaflets with severity values that ranged from 0.4 to 53.7%. Twenty raters [10 experienced (ER) and 10 inexperienced (IR)] validated the SADs by assessing the same set of 50 images twice, the first without SADs and the second using it as an aid. The SADs significantly improved both accuracy and precision for IR as evidenced by increases from 0.86 to 0.98 in the coefficients of bias (Cb) from 0.93 to 0.98 in correlation coefficient (r) and from 0.86 to 0.96 in overall agreement [Lin's concordance correlation coefficients (ρc)] without and with SADs, respectively, whereas for ER only precision (r) was improved by SADs. The SWM estimates were also more reliable because inter-rater reliability (coefficient of determination, R2) was significantly increased for both ER and IR by using SADs. Therefore, the SADs presented is thought to be a valuable tool to provide accurate, precise and reliable estimates of the SWM on common bean leaflets in epidemiological studies, evaluation of disease control methods, assessment of aggressiveness of pathogen isolates, disease resistance and other types of surveys regarding the common beans-S. sclerotiorum interaction.Item Tratamento de sementes com fungicidas e inseticidas como redutores dos efeitos do estresse hídrico em plantas de soja(Ciência Rural, 2011-07) Debona, Daniel; Balardin, Ricardo Silveiro; Silva, Felipe Dalla Lana da; Corte, Gerson Dalla; Favera, Diego Dalla; Tormen, Nédio RodrigoO objetivo do trabalho foi avaliar o efeito de quatro tratamentos de sementes: água (T1), carbendazim + thiram (T2), fipronil + tiofanato metílico + piraclostrobina (T3) e abamectina + thiamethoxam + fludioxonil + mefenoxan + thiabendazole (T4) sobre parâmetros de crescimento de plantas de soja submetidas a dois regimes hídricos (presença e ausência de estresse hídrico) estabelecidos logo após a emergência das plântulas. O experimento foi conduzido em casa de vegetação e campo. Na casa de vegetação, nos tratamentos sem estresse hídrico, foram feitas quatro irrigações por dia e, nos tratamentos com estresse hídrico, foi realizada uma irrigação a cada três dias. Neste ensaio, foi avaliada a estatura de plantas, comprimento radicular, volume radicular, massa seca da parte aérea, massa seca radicular e área foliar. No ensaio de campo, o estresse hídrico foi estabelecido pela construção de túneis baixos de polietileno que impediram o fornecimento de água pela irrigação e chuva. No campo, foram avaliados estatura de planta, teor relativo de clorofila, emergência, ataque de lagarta-elasmo e rendimento de grãos. Nos dois ambientes, as plantas foram mantidas sob estresse até 28 dias após a emergência. Em casa de vegetação, todos os parâmetros foram influenciados pelo tratamento de sementes na presença e ausência de estresse hídrico. No campo, o tratamento com fipronil + tiofanato metílico + piraclostrobina (T3) e abamectina + thiamethoxam + fludioxonil + mefenoxan + thiabendazole (T4) proporcionaram maior estatura de planta e teor relativo de clorofila em ambos os regimes hídricos e maior emergência e rendimento de grãos em plantas sem e com restrição hídrica, respectivamente. Conclui-se que o tratamento de sementes com esses produtos promove alterações benéficas nas plantas, aumentando sua tolerância ao estresse hídrico, com efeito positivo sobre o rendimento de grãos da soja.