O fungo Sclerotinia sclerotiorum, agente causal do mofo branco, encontra-se disseminado em todo o país e afeta mais de 400 espécies de plantas, dentre elas a cultura da soja, causando danos consideráveis no rendimento. A transmissão do patógeno ocorre por meio de sementes contendo micélio dormente ou pela presença de escleródios no lote, os quais podem permanecer viáveis por um longo período, dificultando o manejo da doença. Este trabalho teve como objetivos verificar a viabilidade do patógeno em sementes durante o armazenamento e seu efeito sobre o poder germinativo; comparar tamanhos de amostras de sementes visando à detecção do fungo; e avaliar a sensibilidade in vitro de S. sclerotiorum a fungicidas. Para avaliação da sobrevivência do patógeno, sementes de soja foram inoculadas, artificialmente, com três isolados de S. sclerotiorum, e armazenadas em duas condições, câmara fria e seca (20 ºC e 45% UR) e ambiente não controlado, durante oito meses. A cada dois meses foram realizados testes de sanidade pelo meio de cultura ágar-bromofenol (Neon), utilizando-se 4 repetições de 100 sementes, e testes de germinação, com 4 repetições de 50 sementes, pelo método do rolo de papel. No experimento de amostragem foram avaliadas dez amostras de sementes de soja pelo método do meio Neon, comparando-se quatro tamanhos de amostra: 400, 800, 1600 e 2400 sementes. Para avaliação da sensibilidade in vitro de S. sclerotiorum a fungicidas, foram utilizados 13 ingredientes ativos, em 7 doses e 5 repetições. Os valores da concentração inibitória de 50% (CI50) e 100% (CI100) foram estimados com base na percentagem de inibição do crescimento micelial. Além disso, realizaram-se a quantificação e pesagem dos escleródios formados após 15 dias de incubação. A presença do patógeno S. sclerotiorum, afetou negativamente a germinação das sementes, com redução média de 32% em relação à testemunha. Verificou-se diferença entre os isolados com relação à agressividade. O patógeno sobreviveu nas sementes em ambos os ambientes de armazenamento, porém, em ambiente controlado a redução na geminação das sementes foi de 14% e na incidência do fungo de 16%, enquanto que, em laboratório, esta redução foi de 23% na germinação e de 62% na incidência. Não houve diferença estatística com relação à quantidade de sementes amostradas na detecção de S. sclerotiorum, entretanto, constatou-se maior frequência de ocorrência do patógeno à medida que o número de sementes amostrado foi maior. Todos os fungicidas foram capazes de reduzir o crescimento micelial de S. sclerotiorum, bem como a produção de escleródios, sendo que os ingredientes ativos piraclostrobina, carbendazim, tiabendazol e tiofanato metílico, além de apresentarem CI50 inferior a 1 mg L-1, também inibiram totalmente a formação de escleródios em concentrações inferiores a 5 mg L-1. / The fungus Sclerotinia sclerotiorum, the causal agent of white mold is spread throughout the country and affects more than 400 species of plants, including soybean, causing considerable decrease in yield. The pathogen transmission occurs through seeds with dormant mycelium or by the presence of sclerotia in the lot, which can remain viable for a longer period, making hard the disease management. This study aimed to verify the viability of the pathogen in seeds during the storage period and its effect on germinative power; compare sizes of seed samples to determine the presence of the fungus; and to evaluate the in vitro sensibility of S. sclerotiorum to fungicides. To determine the pathogen survival, soybean seeds were inoculated artificially with three isolates of S. sclerotiorum, and stored into two conditions, cold and dry chamber (20 °C and 45% RU) and in uncontrolled environment, for eight months. Every two months health tests were performed by culture media bromophenol agar (Neon), using 4 repetition of 100 seeds, and germination tests, with 4 repetition of 50 seeds, by the method of the paper roll. During the experiment of sampling, ten samples of soybean seeds were evaluated by the method of media Neon, comparing four sample sizes: 400, 800, 1600 and 2400 seeds. To evaluate the in vitro sensibility of S. Sclerotinia to fungicides were used 13 active ingredients, in 7 doses and 5 repetitions. The values of the 50% inhibitory concentration (IC50) and 100% (IC100) were estimated based on the percentage inhibition of the mycelial growth. In addition, it was performed the quantification and weighing of sclerotia formed after 15 days of incubation. The pathogen S. sclerotiorum in soybean seeds affected negatively the germination of seeds, with an average reduction of 32% compared to the control. There was difference between the isolates in relation to aggressiveness. The pathogen survived in seeds in both storage environments, however, under controlled environment, the decrease in the germination of the seeds was 14% and in its incidence was 16%, while in laboratory this reduction was 23% in the germination and 62% in the incidence. There was no statistical difference in the quantity of seeds sampled in the detection of S. sclerotiorum, however, a higher frequency of pathogen occurrence was verified as the number of sampled seeds was enlarged. All fungicides were able to reduce the mycelial growth of S. sclerotiorum and sclerotia production, and the active ingredients pyraclostrobin, carbendazim, thiabendazole and thiophanate methyl, besides having IC50 of less than 1 mg L-1 also completely inhibited the formation of sclerotia in concentrations less than 5 mg L-1.

Made available in DSpace on 2014-06-11T19:22:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-06-20Bitstream added on 2014-06-13T19:27:15Z : No. of bitstreams: 1 christovam_rs_me_botfca.pdf: 614690 bytes, checksum: 308a3ce40b6f8d645291b92daff32733 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Com o intuito de melhorar a eficiência de controle de Phakopsora pachyrhizi, o presente trabalho avaliou diferentes técnicas de pulverização sobre os depósitos, e parâmetros de produção: classificação dos grãos por peneiras e peso de 1000 sementes e a produtividade da cultura. Seis experimentos foram conduzidos em área experimental da FCA/UNESP – Campus de Botucatu, na cultura da soja (var. Conquista), quatro na safra 2006/07 e dois na safra de 2007/08. O experimento 1 foi conduzido no delineamento em blocos ao acaso com 8 tratamentos e quatro repetições, totalizando 32 parcelas. Os tratamentos foram distribuídos no esquema fatorial 4 x 2 (quatro níveis de ar 0, 9, 11 e 29 km h-1 combinados a dois ângulos de aplicação 0˚ e 30˚) com pontas de jato plano AXI 110015. As parcelas foram dimensionadas em 8,0 x 10,0 m (largura x comprimento). De cada parcela foram selecionadas, ao acaso, dez plantas para a amostragem dos depósitos da pulverização. À cada planta foram fixados alvos artificiais (papel filtro na dimensão 3 x 3 cm), dois na parte superior e dois na parte inferior das plantas e, em cada parte da planta um na superfície abaxial e outro na superfície adaxial do mesmo folíolo. Para avaliação dos depósitos, foi utilizada uma substância cúprica marcadora e a quantificação dos depósitos foi por espectrofotometria. O experimento 2 foi conduzido no mesmo local e os tratamentos distribuídos no mesmo delineamento do experimento anterior, acrescido da testemunha (plantas não tratadas). No estádio de desenvolvimento R 2 e R 5.2, foram realizadas pulverizações com um fungicida triazol à 142 L ha-1. As avaliações do número de pústulas/cm² em folíolos retirados da parte inferior da planta foram realizadas semanalmente. Nos experimentos 3 e 4 foram comparadas quatro tecnologias de aplicação: pulverização convencional (sem ar); pulverização com... / In order to improve control efficiency of Phakopsora pachyrhizi the present research evaluated different spraying techniques on spray deposits and yield parameters: classification of the seeds by sieving and the weight of 1000 seeds and the productivity of the crops. Six experiments were carried out in the experimental area of FCA/UNESP – Botucatu, SP, on soybean crop (Conquista variety). Four of these experiments on the 2006/07 crop and two in the 2007/08 crop were carried out. The first experiment was set in blocks at random design with 8 treatments and four repetitions, totalysing 32 parcels. The treatments were distributed in the squeme 4 x 2 (four air levels 0, 9, 11 and 29 km h-1 combined at two application angles, 0˚ and 30˚) using flat fan nozzles AXI 110015 type. The dimensions of the parcels were 8,0 x 10,0 m (length x width). In each parcel were selected, at random, ten plants to samplify the spray deposits. Artficial targets (filter paper with 3 x 3 cm) were fixed on each plant, two in the upper part and two at the bottom part of the plants and, in each part there was one target the abaxial and another one in the adaxial surface of the same leaflet. For deposits evaluation a tracer cupric substance was used and the spray deposits were quantified by spectrophotometry. The second experiment was carried out in the same place and the treatments were distributed in the same experimental design, more check plot (non treated plants). In R 2 and R 5.2 growth stages it was sprayed a triazol fungicide at 142 L ha-1. Evaluations of the number of pustules cm-2 on leaflets that were removed from the lower part of the plants were realized weekly. On the third and fourth experiments four application technologies were compared: conventional spraying (whitout air) and spraying with the help of air in boom spray at 9, 11 and 29 km h-1 of the air speed on spray deposits and to control... (Complete abstract click electronic access below)

Orientador: Carlos Gilberto Raetano / Banca: Marcelo da Costa Ferreira / Banca: Fernando Cesar Bauer / Banca: Silvio José Bicudo / Banca: Vilson Luis Kunz / Resumo: Com o intuito de melhorar a eficiência de controle de Blumeria graminis Tritici e Puccinia Tritici na cultura do trigo, o presente trabalho objetivou avaliar diferentes técnicas de pulverização sobre os depósitos, controle de oídio e ferrugem da folha, bem como sobre a produtividade da cultura. Oito experimentos foram conduzidos na área experimental da FCA/UNESP - Campus de Botucatu, na cultura do trigo (cultivar IAC-370), sendo divididos em duas fases: quatro na área didática do Departamento de Produção Vegetal - Agricultura (Fase I) e quatro na área cascalheira (Fase II) na safra agrícola de 2009. O experimento 1 foi conduzido no delineamento em blocos ao acaso com 6 tratamentos e quatro repetições, totalizando 24 parcelas. Os tratamentos foram distribuídos no esquema fatorial 3 x 2 (três níveis de ar: 0, 15 e 29 km h-1 combinados a dois volumes de pulverização: 100 L ha-1 com pontas de jato plano XR 110015 e 200 L ha-1 com pontas de jato plano XR 11003). As parcelas foram dimensionadas em 8,0 x 10,0 m (largura x comprimento). De cada parcela foram selecionadas, ao acaso, 20 plantas para amostragem dos depósitos da pulverização. Para avaliação dos depósitos, foi utilizada uma substância marcadora (corante Azul Brilhante) na concentração de 0,15% do volume da calda de pulverização e a quantificação dos depósitos foi por espectrofotometria. O experimento 2 foi conduzido no mesmo local e os tratamentos distribuídos no mesmo delineamento do experimento anterior, acrescido da testemunha (plantas não tratadas). Nos estádios de desenvolvimento 32 (segundo nó visível) e 45 (emborrachamento completo) foram realizadas pulverizações com um fungicida triazol 2 (tebuconazole) à 100 e 200 L ha-1. A severidade das doenças oídio e ferrugem da folha foram avaliadas através... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In order to improve the control efficiency of Blumeria graminis Tritici and Puccinia Tritici in wheat crop, this study aimed to evaluate different spraying techniques on spray deposits, the control of wheat powdery mildew and wheat leaf rust, as well as crop productivity. In general, eight experiments were conducted at experimental area of FCA / UNESP - Botucatu city, in the wheat crop (IAC-370 variety) being divided into two steps: four experiments were carried out at experimental area of Plant Production - Agriculture Department (Step I) and others four experiments were performed at experimental area entitled Cascalheira (Step II) during 2009 season. The first experiment was carried out in randomized blocks with six treatments and four replications, totaling 24 plots. The treatments were arranged in a factorial scheme 3 x 2 (three air speed levels: 0, 15 and 29 km h-1 combined with two spray volumes 100 L ha-1 produced by flat fan nozzle XR 110 015 and 200 L ha-1 produced by flat fan nozzle XR 11003. The plots were dimensioned with 8.0 x 10.0 m (width x length). For each plot, it was selected 20 plants at random, which these plants were utilized to quantify spray deposits. For spray deposits evaluation, it was used a tracer substance (Brilliant Blue dye) in the 0.15% of spray volume concentration and the spray deposits quantification was made by spectrophotometer. The second experiment was carried out at the same place and the treatments were arranged in the same design from the previous experiment, plus a control treatment (untreated plants). In the growth stages 32 (second visible node) and stage 45 (complete boot), it was sprayed a triazol fungicide (tebuconazole) with... (Complete abstract click electronic access below) / Doutor

No Brasil, a soja ocupa a maior área cultivada. Problemas relacionados com doenças fúngicas na cultura têm sido responsáveis por perdas de produtividade de grãos de até 95%. A utilização de compostos a base de piraclostrobina (estrobilurina) tem provido aumento de produtividade e controle de doenças, principalmente da ferrugem asiática, considerada uma das principais doenças da soja no momento. Visando um aporte à pesquisa nas respostas fisiológicas da cultura, este estudo objetivou avaliar o efeito fisiológico de um fungicida a base da estrobilurina piraclostrobina em diferentes cultivares de soja. Realizaram-se dois experimentos, de novembro de 2005 a maio de 2006, no campo experimental da Escola Superior de Agricultura \"Luiz de Queiroz\", utilizando as variedades cultivadas \'M-SOY 8008 RR\' e \'BRS 245 RR\' e um experimento conduzido com a variedade cultivada \'BRS Conquista\', em casa-de-vegetação (condições parcialmente controladas), de janeiro a maio de 2007. Foram realizadas medidas fisiológicas (fotossíntese líquida, respiração, síntese de etileno e atividade da enzima nitrato redutase), fenométricas (fitomassa seca de folhas, caule e total e área foliar), além da produtividade. Os dados obtidos nos ensaios a campo foram utilizados nos modelos propostos por Van Keuler e Wolf (1986). Nos dois experimentos a campo, o delineamento experimental foi de blocos ao acaso com três tratamentos (T1: sem aplicação de fungicida, T2: duas aplicações da estrobilurina piraclostrobina e T3: duas aplicações de tebuconazol - triazol - em R1 e R5.1) com 4 repetições. Em casa-de-vegetação, o delineamento adotado foi o de blocos ao acaso com dois tratamentos (T1: aplicação da estrobilurina piraclostrobina e T2: sem aplicação) e cinco repetições. Na variedade cultivada \'M-SOY 8008 RR\', a aplicação da estrobilurina piraclostrobina no estádio fenológico R1 e R5.1 incrementa a taxa fotossintética nos dois períodos de aplicação. A atividade da enzima nitrato redutase somente é incrementada quando a aplicação é realizada no estádio fenológico R1. A taxa respiratória decresce após a aplicação da estrobilurina piraclostrobina (estádio fenológico R5.1). A estrobilurina piraclostrobina incrementa a taxa de assimilação bruta de CO2 da planta e a taxa de assimilação líquida de CO2 nas vagens, a massa de 1000 grãos e a produtividade de 13 e 4 sacas ha-1 em relação ao tratamento sem aplicação e ao tratamento com aplicação de triazol, respectivamente. Em relação a variedade cultivada \'BRS 245 RR\', a estrobilurina piraclostrobina aumenta o acúmulo de fitomassa seca de folhas, caule e total e da área foliar em torno de 14 dias após a primeira aplicação, mantida até o final do ciclo. Os resultados obtidos em casa-de-vegetação revelaram que a aplicação da estrobilurina piraclostrobina aumenta a taxa fotossintética e atividade da enzima nitrato redutase até o 7 dias após a aplicação, com valores máximos aos 7 DAA para a fotossíntese e ao 0 DAA para a atividade da enzima nitrato redutase. A condutância estomática e a transpiração aumentaram até 3 dias após a aplicação, momento onde é verificado o máximo efeito. O decréscimo na taxa respiratória é mantido até os 7 DAA, entretanto a biossíntese de etileno é inibida progressivamente até os 18 DAA. Com base nos resultados, conclui-se que a aplicação da estrobilurina piraclostrobina em soja causa aumento da atividade fisiológica ocasionando incremento da produtividade de grãos, sendo que a maior atividade na taxa de assimilação de carbono e nitrogênio ocorre até o os 7 DAA. / In Brazil, the soybean is one of the most cultivated crop. However, problems related to fungal diseases caused losses in yield up to 95%. The use of pyraclostrobin had provided increase in yield and diseases control, as Asian rust mainly, considered one of the main soybean disease actually. With the purpose of studying the physiological effect of the pyraclostrobin (strobilurin) application on soybean crop, three experiments were carried out at Piracicaba, State of São Paulo, Brazil (University of São Paulo, Escola Superior \"Luiz of Queiroz\"), using different cultivars (two field experiments, from November 2005 to May 2006, with \'M-SOY 8008 RR\' and \'BRS 245 RR\' cultivar and one greenhouse experiment, from January to May 2007, with \'BRS Conquista\' cultivar). Physiological (net photosynthesis, respiration, ethylene production and the nitrate reductase - enzyme - activity) and phenometric analysis (total - shoot + root - leaves and stem dry mass and leaf area) and soybean yield were evaluated. The statistical field experiment design was complete randomized block design with three treatments (T1: no fungicide application; T2: two applications of pyraclostrobin and T3: two applications of tebuconazole - triazol - at R1 and R5.1 soybean phenological stages) and four replications. The statistical greenhouse experiment design also was complete randomised block design with two treatments (T1: pyraclostrobin application and T2: no fungicide application) and five replications. The field experiment observed data had been used according to the Van Keuler and Wolf (1986) models. The nitrate reductase enzyme activity was increased when the fungicide was applied at R1 stage. The respiratory rate decreases soon after the pyraclostrobin application (stage R5.1). The pyraclostrobin (strobilurin) increased: (i) the plant CO2 gross assimilation rate; (ii) the pod CO2 net assimilation rate; (iii) the mass of 1000 seeds and (iv) yield (13 and 4 bags ha-1 in relation to T1 and T3, respectively). In relation to \'BRS 245 RR\' cultivar, the pyraclostrobin increased leaves, stem and total (shoot + root) dry mass and leaf area from 14 days after first application to end of the crop cycle. The greenhouse observed data demonstrated that the pyraclostrobin application increased the photosynthesis rate (maximum values occurred 7 days after application - DAA) and the nitrate reductase enzyme activity (maximum values occurred 0 DAA) until 7 DAA. The physiological effect of pyraclostrobin application on the stomatal conductance and transpiration rate occured until 3 DAA, period of maximum effect. The respiratory rate decreased until 7 DAA, however the ethylene biosynthesis was inhibited gradually until 18 DAA. The observed data allows to conclud that the pyraclostrobin application increased the soybean physiological activity and the yield, being that the highest activity in the carbon assimilation and nitrogen rate occurred until the 7 DAA.

Made available in DSpace on 2017-07-10T17:40:44Z (GMT). No. of bitstreams: 1 Darci_Fontoura.pdf: 1899459 bytes, checksum: 8c49d8ad8328dec589d5f17122d1bf18 (MD5) Previous issue date: 2013-08-16 / In recent years farmers have gradually increased the use of chemical pesticides to mitigate the losses from diseases in corn. An alternative to reduce the use of such products may be the application of resistance inducer, taking advantage of latent genetic resistance, causing less negative impact on the environment and human health. Although, there may be an energetic expense with this induction which could hold up this form of control. With the objective of verifying the resistance induction in off-season (safrinha) corn by acibenzolar-S-methyl (ASM) and phosphorylated mannanoligosaccharide (MOS), experiments were conducted with four corn hybrids (30F90H, 30K64H, 30K73H and P4042H) in two consecutive years (2011 and 2012) in off-season environment in the municipality of Toledo - PR. In addition to the resistance inducers, a fungicide (azoxystrobin + ciproconazole) was applied, as well as water as a check. A randomized block design, with a triple factorial scheme, plus an additional treatment and three replications was used. The factors were: (A) hybrid in four levels (B) product in three levels and, (C) dose in three levels. The additional treatment was carried out with water spray, representing the level zero of the dose factor. The application of the products happened in phenological stages V8 and VT. There was observed an incidence of diverse plant pathogens in the two consecutive years, on the same hybrids, in the same location and under the same manageable conditions, probably due to diverse climatic conditions from one year to another, although hypersensitive response occurred in both years under MOS treatment. In the 2011 off-season, there was an incidence of Exserohilum turcicum, a necrotrophic pathogen, and no damaged kernels were found, while in the 2012 off-season, there was an incidence of Puccinia polysora, a biotrophic pathogen, plus significant percentage of damaged kernels. None of the applied products affected the traits plant height, ear placement, content of foliar nitrogen and percentage of damaged kernels. There was significant effect of resistance inducers on the hypersensitivity response and root lodging, without reducing the productivity compared to the water treatment. MOS increased hypersensitivity response severity and ASM reduced root lodging. The fungicide treatment (azoxystrobin + ciproconazole) showed better control of foliar diseases (P. polysora and E. turcicum) and higher yield in both years, and in 2011 it reduced stalk lodging and increased the mass of thousand kernels / Nos últimos anos os produtores tem aumentado gradativamente o uso de defensivos químicos para amenizar os prejuízos com doenças da cultura do milho. Uma alternativa visando diminuir o uso de tais produtos poderá ser a aplicação de indutores de resistência, tirando proveito da resistência genética latente, gerando menor impacto negativo sobre o meio ambiente e a saúde humana. Entretanto, poderá haver elevado dispêndio de energia nessa indução que torne inviável essa forma de controle. Objetivando verificar a indução de resistência em milho safrinha pelos indutores acibenzolar-S-metil (ASM) e mananoligossacarídeo fosforilado (MOS), foram conduzidos experimentos com quatro híbridos de milho (30F90H, 30K64H, 30K73H e P4042H), em dois anos consecutivos (2011 e 2012), na safrinha no município de Toledo PR. Além dos indutores de resistência, realizou-se também tratamento com fungicida (azoxistrobina + ciproconazol), além de água como testemunha. Foi utilizado delineamento experimental de blocos casualizados com esquema fatorial triplo e tratamento adicional, em três repetições. Os fatores testados foram: (A) híbrido em quatro níveis, (B) produto em três níveis e, (C) dose em três níveis. O tratamento adicional foi realizado com pulverização de água, representando o nível zero do fator dose. As aplicações dos produtos aconteceram nos estádios fenológicos V8 e VT. Observou-se incidência de patógenos distintos nos dois anos consecutivos sobre os mesmos híbridos, no mesmo local e nas mesmas condições de manejo, provavelmente em função da condição climática distinta de um ano para o outro, embora a resposta de hipersensibilidade tenha acontecido em ambos os anos no tratamento com MOS. Na safrinha de 2011 houve incidência de Exserohilum turcicum, um patógeno necrotrófico, e não foram encontrados grãos ardidos, enquanto que na safrinha de 2012 houve incidência de Puccinia polysora, um patógeno biotrófico, além de significativo percentual de grãos ardidos. Nenhum dos produtos aplicados influenciou as características altura de planta, altura de inserção de espiga, teor de nitrogênio foliar e percentual de grãos ardidos. Houve efeito dos indutores de resistência quanto à resposta de hipersensibilidade e acamamento em função da raiz, sem redução da produtividade em relação ao tratamento com água. MOS aumentou a severidade da resposta de hipersensibilidade e acibenzolar-S-metil reduziu o acamamento em função da raiz. O tratamento com fungicida (azoxistrobina + ciproconazol) apresentou o melhor controle das doenças foliares (P. polysora e E. turcicum) e a maior produtividade em ambos os anos, sendo que em 2011 ainda reduziu o acamamento de colmo e aumentou a massa de mil grãos

Os efeitos de EPA e DHA sobre a função de neutrófilos foram comparados. Para isso, foram realizados experimentos em neutrófilos isolados de ratos. Foram analisadas células com a membrana plasmática íntegra e fragmentação de DNA com o intuito de determinar as concentrações não tóxicas de EPA e DHA. Aumento da produção de peróxido de hidrogênio ocorreu a partir de concentrações menores de DHA (50 <font face=\"Symbol\">mM comparado com 100 <font face=\"Symbol\">mM de EPA). Já para a produção de ânion superóxido, EPA estimulou em doses menores (12.5 <font face=\"Symbol\">mM e o DHA em 100 <font face=\"Symbol\">mM). Ambos AGs aumentaram a síntese e liberação das citocinas CINC-2 e TNF-<font face=\"Symbol\">&#945 e não modificaram a produção de IL1-<font face=\"Symbol\">b e óxido nítrico após incubação das células por 18 horas. Somente DHA elevou a capacidade fagocitária e a atividade fungicida dos neutrófilos. EPA e DHA apresentaram efeitos distintos na produção de citocinas, fagocitose e atividade fungicida dos neutrófilos. Já na produção das EROS, EPA e DHA apresentaram efeitos similares, embora em concentrações diferentes. / The effects of eicosapentaenoic (EPA) and docosahexaenoic (DHA) on neutrophil function were compared. For this purpose, experiments were performed in isolated rat neutrophils. Cells with intact plasma membrane and DNA fragmentation were analyzed in order to determine the non-toxic concentrations of EPA and DHA. Production of H2O2 was increased in lower concentrations of DHA (50 <font face=\"Symbol\">mM compared to 100 <font face=\"Symbol\">mM of EPA). For production of O2 -, EPA stimulated at lower doses (12.5 <font face=\"Symbol\">mM compared to 100 <font face=\"Symbol\">mM of DHA). Both FAs increased synthesis and release of cytokines, CINC-2 and TNF-<font face=\"Symbol\">&#945, and did not change the production of IL-1<font face=\"Symbol\">b and nitric oxide after incubation of the cells for 18 hours. Only DHA increased the phagocytic capacity and fungicidal activity of neutrophils. These FAs showed distinct effects on cytokine production, phagocytosis capacity and fungicidal activity by neutrophils. For production of ROS, both EPA and DHA had similar actions, although at different concentrations.

Fungi in the genus Trichoderma have been characterized as biocontrol agents of plant pathogens since the 1930s. The use of biologicals for disease management has increased in recent years, typically marketed as a safer alternative to chemical applications. However, biologicals often lack consistent control across varying environmental conditions. To overcome the loss in efficacy due to environmental conditions, biologicals can be combined with common fungicide seed-treatments to provide improved control. Additionally, the presence of a biological organism could slow the development of a pathogen population. Greenhouse trials were conducted to determine the baseline root colonization of three Trichoderma spp. used in conjunction with five commonly used seed treatments. In field trials, a stand-alone treatment of the Trichoderma isolates was assessed for management of Rhizoctonia root rot (caused by Rhizoctonia solani) and frogeye leaf spot (caused by Cercospora sojina). The greenhouse trial provided evidence that isolates of T. virens and T. hamatum can colonize the roots of plants in which seeds were treated with metalaxyl + prothioconazole + penflufen or metalaxyl + prothioconazole + penflufen + fluopyram. Surprisingly, in the Rhizoctonia root rot trials, the soybean seedlings treated with Trichoderma spp. had significantly reduced stand compared to the R. solani inoculated control. For the frogeye leaf spot trial, an application of T. virens conidial suspensions as a foliar treatment significantly (P ≤ 0.10) reduced frogeye leaf spot severity of soybean compared to a non-treated control. Future research is warranted to better understand the potential efficacy in additional environments and the mechanism(s) of action used by the Trichoderma isolates evaluated in these experiments.

Some aspects of the presence of systemic endophytic fungi in agriculturally important New Zealand grasses were studied in relation to plant breeding. Seedling resistance to adult Argentine stem weevil feeding in perennial ryegrass, Italian ryegrass and tall fescue was found to be related to the presence of their respective Acremonium endophytes in the seed rather than to plant genetic resistance. In addition a study of perennial ryegrass revealed that this resistance was independent of endophyte viability. The seedling resistance conferred by the endophyte of Italian ryegrass was found to be beneficial for field establishment. This endophyte differs from that in perennial ryegrass and tall fescue in that it does not confer resistance to Argentine stem weevil on mature plants, but only on seedlings. The extent of plant genetic seedling tolerance to adult Argentine stem weevil feeding was limited to broad inter-specific differences, with tall fescue more tolerant than perennial ryegrass and both of these more tolerant than Italian ryegrass. This ranking corresponds with previous observations on feeding preference on mature plants. A study of factors affecting the concentration of endophyte mycelia in infected seed of perennial ryegrass revealed that plant genetic factors had little effect. The major factors studied were: 1) the endophyte concentration in the maternal parent plant directly influenced the endophyte concentration in the seed. 2) nitrogen fertilizer applications to a seed crop reduced the concentration of mycelia in the seed, with earlier applications having a greater effect. 3) application of the fungicide propiconazole (Tilt) to a seed crop reduced the endophyte concentration in the seed. 4) the endophyte concentration in the seed was found to directly influence the endophyte concentration in seedlings, six month old plants and that of seed harvested from a first year seed crop. As there have been no previous reports of tetraploid perennial ryegrass cultivars with endophyte an experiment was conducted to determine if these could be developed by the standard procedure of colchicine treatment. The results revealed that endophyte was retained following colchicine treatment.

<p>Mercury contamination in aquatic ecosystems is a concern as anaerobic aquatic sediments are the primary regions of methylmercury production in freshwater and coastal regions. Methlymercury is a bioaccumulative neurotoxin, and human exposure to methylmercury can result in impaired functioning of the central nervous system and developmental disabilities in children. To minimize the risk of human exposure to methylmercury, it is important to be knowledgeable of the various sources which can supply mercury to aquatic ecosystems as well as have a complete understanding of the biogeochemical processes which are involved in methylmercury production in aquatic systems. In this dissertation work, both mercury biogeochemical speciation in anaerobic aquatic sediments and sources of mercury to aquatic systems were addressed. </p><p>The biogeochemical speciation of mercury is a critical factor which influences the fate and transformation of mercury in aquatic environments. In anaerobic sediments, mercury chemical speciation is controlled by reduced sulfur groups, such as inorganic sulfide and reduced sulfur moieties in dissolved organic matter (DOM). The formation of mercury sulfide nanoparticles through stabilization by dissolved organic matter (DOM) was investigated in precipitation studies using dynamic light scattering. Mercury sulfide nanoparticles (particle diameter < 100 nm) were stabilized through precipitation reactions that were kinetically hindered by DOM. To further investigate the interaction between DOM and metal sulfides, similar precipitation studies were performed using zinc sulfide and a number of DOM isolates (humic and fulvic acids) representing a range of DOM properties. The results of these experiments suggest that the mechanism of metal sulfide particle stabilization may be electrostatic or electrosteric, depending on the nature of the DOM molecule.</p><p>The mercury that is methylated in aquatic systems enters these environments via a number of sources, including atmospheric deposition, landscape runoff and other industrial and municipal activities. In two separate field studies, two potential sources of mercury to aquatic systems were investigated: landscape runoff and coal combustion products. The mercury loading to aquatic environments from these sources and their potential for transformation to methylmercury were investigated.</p><p>Landscape runoff from a Duke University campus catchment (Durham, NC) was identified as a source of mercury to a stream-wetland. The source of mercury to the runoff was likely from a `legacy' source of mercury; the historic application of mercury fungicide compounds to turf grass during the 20th century. Downstream of the point where the runoff was discharged to the stream-wetland, methylmercury concentrations were detected in stream sediments (up to 11% of total mercury), suggesting that this legacy mercury could be transformed to methylmercury. </p><p>The environmental impact of coal combustion products (CCPs) with respect to mercury and methylmercury was also investigated in a river system (Roane County, TN) that was inundated with fly ash and bottom ash from the Tennessee Valley Authority Kingston coal ash spill in 2008. Elevated total mercury and methylmercury sediment concentrations (relative to upstream sediments) were detected in regions impacted by the ash spill, and our biogeochemical data suggested that the ash may have stimulated methylmercury production in river sediments.</p><p>The results of this dissertation work address the formation of mercury sulfide (along with zinc sulfide) nanoparticles in anaerobic aquatic sediments. In the current mercury methylation paradigm, dissolved mercury species such as Hg(SH)02(aq) and HgS0(aq) are assumed to be the only mercury species that are available for methylation. The results of this dissertation work suggests that in previous studies, HgS0(aq) may have been mistaken as mercury sulfide nanoparticles which may be formed in under supersaturated conditions (with respect to HgS(s)) where DOM is present. Mercury sulfide nanoparticles are a mercury biogeochemical species that has been largely ignored in the research literature and whose role in the mercury biogeochemical cycle and in mercury methylation remains to be investigated.</p><p> This dissertation work also identifies potential sources of mercury to aquatic systems, namely, landscape runoff and CCPs. Atmospheric deposition is currently considered to be the major source of mercury to inland aquatic water bodies compared to sources such as landscape runoff and CCPs. However, in the watershed studied in this dissertation, landscape runoff was identified as a larger source of mercury than atmospheric deposition, suggesting that these so-called `minor' sources may actually be major sources of mercury to watersheds depending on land usage, and should be considered in watershed models. Furthermore, the environmental hazards of mercury-associated with CCPs has typically been determined through leaching experiments, such as the Toxicity Characteristic Leaching Procedure (TCLP), which are not representative of environmental conditions and do not predict that CCPs may influence mercury methylation in aquatic sediments. Thus, in this dissertation work, we suggest that leaching protocols such as the TCLP should be re-evaluated. </p><p>Overall, this dissertation work will be useful in future studies examining mercury speciation and bioavailability to methylating bacteria in aquatic sediments, and the formation of metal sulfide nanoparticles in aquatic systems. Additionally, data on sources of mercury will be useful in developing policies for the regulation of these sources and in assessing the risk to human health from mercury methylation.</p> / Dissertation

Azoxystrobin (AZY), a systemic broad-spectrum fungicide, is applied on crops to control soil-borne pathogenic fungi. This study aimed to determine the effects of AZY on non-target plant species and Glomus intraradices Schenck & Smith, an arbuscular mycorrhizal fungus (AMF) associated with plants' roots. We hypothesized that AZY negatively affects AMF viability; and that, if the plants were dependent on this symbiosis, AZY exerts an indirect detrimental effect on plant growth. To test this, three mycotrophic (Phalaris arundinacea L., Solidago canadense L., Geum canadense Jacq.) and one non-mycotrophic (Chenopodium album L.) native plant species were subjected to five AZY doses with or without AMF. Plants were grown for 60 days in a greenhouse, in individual pots, (4 plants X 2 AMF X 5 AZY X 6 replicates), and mesocosms (1 mes. X 2 AMF X 5 AZY X 6 replicates), and harvested 30 days after spraying, and dry mass was taken. Fresh root samples were used for microscopic assessment of AMF colonization. The results from the individual pot experiment show that the effects of AZY on biomass varied across plant species. AZY led to a significant increase in shoot and root mass of P. arundinacea, and a decrease in shoot mass of AMF inoculated G. canadense. The presence of AMF resulted in a significant increase in root and shoot mass of P. arundinacea, and an increase in root mass of S. canadense and shoot mass of C. album. In the mesocosm experiment AZY did not have a significant effect on the measured parameters, although the presence of AMF significantly increased root, shoot, and total dry mass of G. canadense and P. arundinacea. Conversely, AMF significantly decreased shoot and total dry mass of S. canadense. The results suggest that both direct and indirect effects should be taken into account when assessing the impact of pesticides on non-target plant species.