999 resultados para resistência de plantas a doenças
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A mosca da fruta é uma das principais pragas agrícolas. Neste trabalho determinou-se a composição volátil do nutriente FNI 210 (proteína alimentar) e dos extratos de cinco plantas: Cedronella canariensis, Eucalyptus globulus, Laurus novocanariensis, Myrtus communis e Ruta chalepensis e avaliou-se o seu potencial atrativo e repelente em moscas adultas num olfatómetro em Y. A composição volátil do nutriente e dos extratos foi semelhante à encontrada por outros autores e apresentou compostos atrativos para a mosca da fruta. Nos bioensaios com o olfatómetro as moscas foram atraídas à proteína mas a percentagem média de respostas variou de acordo com o sexo, estado sexual, idade e número de indivíduos por grupo sendo mais alta aos 8 dias em grupos de 5. No geral, as fêmeas virgens responderam mais do que as não virgens e mais do que os machos virgens. O número de insetos que se dirigiram à proteína foi superior na primeira repetição nos primeiros 10 e 20 minutos. Contudo, em todos os bioensaios houve um número elevado de indivíduos não responderam. Nos bioensaios das plantas a resposta do mesmo grupo de 5 indivíduos com 8 dias foi testada três vezes no olfatómetro pela ordem seguinte: sem amostra, com proteína e com extrato de planta. Nos três casos as respostas dos adultos variaram de acordo com o sexo e estado sexual. As percentagens médias de respostas aos extratos foram superiores às obtidas nos ensaios sem amostra e menores que à proteína, á exceção do extrato de L. novocanariensis que apresentou um potencial atrativo superior ao da proteína nos machos virgens. Nos testes com o extrato, as respostas ao braço com amostra foram superiores ao braço sem amostra, à exceção das respostas das fêmeas não virgens ao extrato de R. chalepensis, o que sugere ser esta a única planta com potencial repelente.
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Dengue fever, currently the most important arbovirus, is transmitted by the bite of the Aedes aegypti mosquito. Given the absence of a prophylactic vaccine, the disease can only be controlled by combating the vector insect. However, increasing reports of resistance and environmental damage caused by insecticides have led to the urgent search for new safer alternatives. Twenty - um plant s eed extracts from the Caatinga were prepared , tested and characterized . Sodium phosphate ( 50 mM pH 8.0) was used as extractor. All extracts showed larvicidal and ovipositional deterrence activity . Extracts of D. grandiflora, E. contortisiliquum, A. cearenses , C. ferrea and C. retusa were able to attract females for posture when in low co ncentration . In the attractive concentrations, the CE of E. contortisiliquum and A. cearenses were able to kill 52% and 100% of the larvae respectively . The extracts of A. cearenses , P. viridiflora, E. velutina, M. urundeuva and S. brasiliensis were also pupicides, while extracts of P. viridiflora, E. velutina, E. contortisiliquum , A. cearenses, A. colubrina, D. grandiflora , B. cheilantha , S. spectabilis, C. pyramidalis, M. regnelli e G. americana displayed adulticidal activity. All extracts were toxic to C. dubia zooplankton . The EB of E. velutina and E. contortisiliquum did not affect the viability of fibroblasts . In all extracts were identified at least two potential insecticidal proteins such as enzyme inhibitors, lectins and chitin - binding proteins and components of secondary metabolism . Considering all bioassays , the extracts from A. cearenses, P. viridiflora, E. contortisiliquum , S. brasiliensis, E. velutina and M. urundeuva were considered the most promising . The E. contortisiliquum extracts was the only one who did not show pupicida activity, indicating that its mechanism of action larvicide and adulticidal is related only to the ingesti on of toxic compounds by insect , so it was selected to be fragmenting. As observed for the CE , th e protein fractions of E. contortisiliquum also showed larvicidal activity, highlighting that F2 showed higher larvicidal activity and lower en vironmental toxicity than the CE source. The reduction in the proteolytic activity of larvae fed with crude extra ct and fractions of E. contortisiliquum suggest ed that the trypsin inhibitors ( ITEc) would be resp onsible for larvicidal activity . However the increase in the purification of this inhibitor resulted in loss of larvicidal activity , but the absence of trypsin inhibitor reduced the effectiveness of the fractions , indicating that the ITEC contributes to the larvicidal activity of this extract. Not been observed larvicidal activity and adulticide in rich fraction vicilin, nor evidence of the contribution o f this molecule for the larvicidal activity of the extract. The results show the potential of seeds from plant extracts of Caatinga as a source of active molecules against insects A. aegypti at different stages of its development cycle, since they are comp osed of different active compounds, including protein nature, which act on different mechanisms should result in the death of insec
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The sabiá (Mimosa caesalpiniaefolia Benth.) is an endemic species of the Caatinga biome, considered tolerant to salt and water stress. The process of salinization of soil and groundwater and surface water is one of the most important problems of environmental degradation, with its harmful effects being more pronounced in the areas of arid and semiarid regions, and rapidly growing in many parts of the globe, causing problems of the major crop yield. Organic conditioners as barnyard manure, and rice hulls can contribute to reducing the PST, possibly due to the release of CO2 and the production of organic acids during the decomposition of organic matter, and act as sources of calcium and magnesium and inhibit the availability sodium. The intimate association of mycorrhizae and beneficial to plants results in increased uptake of water and nutrients by plants, especially phosphorus, due to their low mobility in soil. The objective of this study was to evaluate the initial growth of thrush seedlings under inoculation with mycorrhizal fungi and fertilized with manure corral and irrigated with water of different salinity levels. The experiment was conducted in greenhouse conditions of vegetation on the premises of the Agricultural School of Jundiaí - UFRN, Campus Macaíba. The adopted statistical design was randomized composed of twelve treatments - three substrates (sterile soil, manure and FMA), four salinity levels (0.2, 1.5, 3.0 and 4.5 dS m-1 ) and five repetitions, totaling sixty experimental units. The results indicate that inoculation with mycorrhizal fungi own contributions to the growth of plants, especially in roots and shoots, which suggests that its application is beneficial in establishing thrush plants in natural conditions, with poor soil in P. Levels salinity caused no effects with statistical significance in plant development, indicating Sabia resistance to it.
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Coffee plants were introduced in Brazil in the Northern State of Para around 1727. Two major diseases have affected coffee trees in the country. One is rust, caused by fungus Hemileia vastatrix and accountable for production losses up to 50%. The other one is Cercospora leaf spot, caused by fungus Cercospora coffeicola endemic to all Brazilian coffee farms and, therefore, economically critical due to production losses both in the plant nursery and in the field. Availability of resistant varieties has been a constant challenge for breeders. Research programs play an important role in the search for new resistant and/or tolerant genotypes, since over time plants can become susceptible to new, genetically variable races of pathogens. This study aimed to evaluate the incidence and severity of such diseases, the resistance of different coffee genotypes to H. vastatrix and C. coffeicola pathogens, as well as the productivity of said genotypes in dense planting system. The experimental design consisted of randomized blocks, with twelve genotypes (treatments) and two replications (blocks). SISVAR® program was used to analyze data and compare them building on Scott-Knott test and Tukey’s test with a probability of 5%. Disease incidence and severity percentage were assessed for both Cercospora leaf spot and rust. Means were used to calculate the area under the disease progress curve (AUDPC) of both diseases. As to rust, the most resistant genotypes were H586-6, IBC 12, and H556-7 H567-6. As to Cercospora leaf spot and productivity, no statistical differences were found across genotypes. The dense planting system did not impair plant development, but favored disease evolution given the microclimate it produces.
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Salmonella Enteritidis, S. Typhimurium and S. Infantis are often associated with cases of human infections worldwide and is transmitted through consumption of contaminated food, particularly those of animal origin, especially chicken meat. This thesis was fractionated into three chapters, the first one relating to general considerations about the topics discussed in the following chapters. The second chapter aimed to evaluate virulence characteristics, antimicrobial resistance and the genetic similarity of 51 strains of S. Infantis isolated in samples of poultry origin from an industry located in the state of São Paulo, Brazil, during the 2009 to 2010 period. The third chapter aimed to analyze 111 strains of S. Enteritidis, 45 of Salmonella Typhimurium and 31 of Salmonella Typhimurium monophasic variant I 4, [5], 12:i:- isolated from chicken carcasses in different brazilian slaughterhouses from 2009 to 2011, and to estimate the risk to human health, based on the presence of virulence genes and antimicrobial resistance, correlating to the pathogenicity profiles (antimicrobial resistance and presence of virulence and resistance genes) with the genetic profile (ribogroup) of the isolates. To evaluate the antimicrobial susceptibility was performed the disk diffusion test for all serotypes of Salmonella, and exclusively to S. Enteritidis and S. Typhimurium, was also verified the minimum inhibitory concentration for ciprofloxacin and ceftazidime antibiotics. The presence of virulence genes invA (invasion), lpfA (fimbriae-adhesion), agfA (fimbriae-biofilm) and sefA (fimbriae-adhesion) were evaluated by PCR. The strains that showed resistance to antibiotics of β-lactams class were evaluated for the presence of resistance genes blaTEM, blaSHV, blaCTX-M and blaAmpC. For resistant strains to quinolones and fluoroquinolones antibiotics classes were searched the qnrA and qnrS genes. The phylogenetic relationship among the isolates was determined by RAPD method for S. Infantis strains, and by ribotyping technique to S. Enteritidis and S. Typhimurium.
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O consumo de frutas e vegetais tem sido associado à prevenção de várias doenças crónicas, nomeadamente doenças cardiovasculares, diabetes, cancro e outras que envolvam processos inflamatórios. As bagas destacam-se pelo seu elevado conteúdo em polifenóis, cujas propriedades antioxidantes contribuem para a manutenção da saúde humana. O presente trabalho teve como alvo de estudo as diferentes partes morfológicas (bagas e folhas) de espécies produtoras de bagas, nomeadamente Elaeagnus umbellata, a Rubus grandofolius, a Sambucus lancolata, a Vaccinium padifolium e a Vaccinium cylindraceum, tendo em vista a sua valorização como produtos alimentares e/ou nutracêuticos. A caracterização físico-química destas espécies permitiu determinar que o teor total de sólidos solúveis (TSS) das bagas varia de 4,4 a 16,5 °Brix. As bagas demonstraram ser a parte morfológica com teor de humidade mais elevado. A análise do perfil fenólico por HPLC-DAD-ESI/MSn, no modo negativo, dos extractos metanólicos mostrou que as folhas apresentam maior conteúdo de compostos fenólicos, comparativamente às bagas. Os ácidos hidroxicinâmicos (derivados dos ácidos cafeicos, cumárico e ferúlico), os ácidos cafeoilquínicos, bem como os flavonóis-O-glicosilados (derivados da quercetina e canferol) predominam nestas espécies. A análise pelo modo positivo permitiu a identificação de antocianinas glicosiladas (delfinidina, cianidina, petunidina, peonidina e malvidina) nas bagas e folhas jovens da espécie Vaccinium padifolium. Os ensaios in vitro de simulação da digestão gastrointestinal permitiram compreender a sua influência na actividade antioxidante dos extractos. Após a digestão, as folhas continuam a apresentar maior capacidade antioxidante do que as bagas. Adicionalmente, concluiu-se que as enzimas presentes neste processo têm menor influência do que o pH e a força iónica dos sucos digestivos. O estudo do efeito inibitório in vitro dos extractos sobre a actividade de enzimas responsáveis pelo metabolismo dos hidratos de carbono permitiu determinar que os viii Joana Pinto (2016) extractos foram mais eficientes na inibição da actividade da α-glucosidase do que na inibição da actividade da α-amilase.
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O presente trabalho aborda a história das principais doenças que assolaram a Europa desde a época medieval à época contemporânea, incluindo a referência às origens, às manifestações e ao tratamento. É igualmente abordada a questão do isolamento das substâncias ativas nas plantas medicinais e farmacológicas até à descoberta do primeiro antibiótico identificado pelo homem – a penicilina, por Alexandre Fleming – e a sua enorme importância no combate aos micro-organismos.
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The crops are affected by pests and diseases that decrease productivity. Among them are the damping off of seedlings that can occur in pre and post-emergence. In bean crops, cucumber and beet these diseases occur, being caused by various pathogens, especialy fitopathogenic fungi. Several measures are used for the controle of such diseases, among them, is the chemical seed treatment fungicides. However, society has become increasingly concerned about the quality and food and environmental contamination, generation a growting search for sensitive products to humans and the environment. The use of essential oils to control plant pathogens is an example of alternative tested by science in the search for less aggressive technologies. This study aimed to evaluate the efficiency of the use of essential oil Aloysia citriodora, in control of pathogens causing damping off in beans, cucumber and beet. This thesis was divided in four chapters, the introductory first, and the other addressing the control of Pythium sp. in beans, Sclerotinia sclerotiorum on cucumber, and Fusarium sp. on beet. The methodology consisted of four experiments in each pathosystem, with all the work done at the Federal Technological University of Parana, Campus Dois Vizinhos. In the first experiment evaluated the fungistatic and fungicidal effect of the essential oil of A. citriodora on PDA in vitro in mycelial growth of pathogens studied. In the second experiment evaluated the in vitro effect of essential oil concentrations of A. citriodora in BD medium on microscope slides, on the germination of sporangia Pythium sp. and conidia Fusarium sp., and in Petri dishes with PDA medium, the sclerotia germination speed index of S. sclerotiorum. In the third experiment, we evaluated in germination test in paper roll (PR), the phytotoxic effect or not the use of essential oil concentrations of A. citriodora in dry bean seed, cucumber and beet. The variables used to assess this experiment were the germination percentage, mediun green mass per plant and average length of seedlings. In the fourth experiment we assessed the effect of treating bean seeds, cucumber and beet with essential oil contents of A. citriodora, seeds in their subsequent substrates contamined with pathogens studied, Pythium sp., S. sclerotiorum and Fusarium sp. In this experiment we used the following variables: percentage of emergence, percentage of post-emergence damping off, green average mass per plant, average length per plant and biochemical analyzes. The biochemistry of plant tissues evaluated were as follows: protein content, enzymatic activities of peroxidases, phenylalanine ammonia-liase (PAL), chitinases and β-1,3-glucanases. The in vitro results show that the essential oil has fungistatic and fungicidal effect on mycelial growth, on sporangia germination, conidia and sclerotia of the pathogens studied in this work, wich may be related to its major components, citral and limonene. The oil also exhibits low phytotoxicity to seeds of the species studied, only in beans decreases germination in most studied dosage (0,25%), cucumber also in the higher dosage (0,25%) reduce the length of seedlings, and beet there were no negative effects to the seedlings. In the test in substrate contaminated with the pathogens, the use of essential oil: increased germination and decreased post emergence damping off of beans seedlings; at a concentration of 0,0625% decreases post emergence damping off in cucumber. In biochemical analyzes found an increase in the enzymatic activity of peroxidases and β-1,3-glucanases on beans, and glucanases on cucumber, and increased enzyme activity of peroxidases on beet, showing action in resistance induction at damping off.
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Soybean plays an important role in the Brazilian agriculture being one of the products most exported by the country. Its yield may be affected by diseases such as white mold, caused by the fungus Sclerotinia sclerotiorum Lib. de Bary, which, under favorable field conditions prevents the crop of expressing all its productive potential. The fungus is cosmopolitan and infects more than 400 species of plants. This disease is difficult to control, and the use of chemicals has not been sufficient to avoid significant losses, thus, this products are expensive and may cause environmental damage. Alternative methods, such as foliar fertilizers based on potassium phosphite, can also be used in the management of this disease. In this context, this work aimed to study different sources of potassium phosphite and its effects in the control of white mold in soybeans, as well as the time of application in culture, its action in inducing plants defense responses and/or its influence over the seeds quality. The effect of phosphites, over the pathogen, was evaluated in vitro, on mycelial inhibition, the mass of dry mycelium and germination of sclerotia. In all tests, the following phosphites were utilized: Phosphite A (P2O5-40%; K2O-20% - 1 L/ha); Phosphite B (P2O5-40%; K2O-28% - 1 L/ha); Phosphite C (P2O5-40%; K2O-20% - 1 L/ha) e Phosphite D (P2O5-30%; K2O-20% - 2,4 L/ha). At the induction of resistance tests were evaluated the synthesis of phytoalexin in soybean cotyledons and the enzymes FAL and POX evaluated in seedlings in growing chamber, sprayed with phosphites and the fungicide fluazinam. Field experiment was carried out at Coronel Domingos Soares-PR, in the 2012/2013 season, in an area with natural infestation of the pathogen. Soybean cultivar BMX Active was no-till seeded with 0,5m between rows. The experimental was laid out as a factorial 5 x 4 scheme (treatment x application time). Phosphites sources were used, as described above, and water was sprayed in the control treatment. Treatments were applied at four different growth stages: V4, V4 + R1, R1 and R2 at the rates recommended by the manufacturer. Soybean yield components and seeds and health and physiological quality were evaluated after harvesting. None of the tested phosphites affected mycelial growth and sclerotia germination or influenced phytoalexin synthesis. Phosphites C and D stood out due to an increasing in the phenylalanine ammonia-lyase activity 48 hours after its inoculation. These same products also induced the synthesis and peroxidases and phosphite C kept the levels of this enzyme elevated up to 72 hours after inoculation. At the field trials, phosphites C and D stood out in the control of white mold. There was no significant interaction of potassium phosphite on physiological and sanitary quality of the seeds.
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O consumo de frutas e vegetais tem sido associado à prevenção de várias doenças crónicas, nomeadamente doenças cardiovasculares, diabetes, cancro e outras que envolvam processos inflamatórios. As bagas destacam-se pelo seu elevado conteúdo em polifenóis, cujas propriedades antioxidantes contribuem para a manutenção da saúde humana. O presente trabalho teve como alvo de estudo as diferentes partes morfológicas (bagas e folhas) de espécies produtoras de bagas, nomeadamente Elaeagnus umbellata, a Rubus grandofolius, a Sambucus lancolata, a Vaccinium padifolium e a Vaccinium cylindraceum, tendo em vista a sua valorização como produtos alimentares e/ou nutracêuticos. A caracterização físico-química destas espécies permitiu determinar que o teor total de sólidos solúveis (TSS) das bagas varia de 4,4 a 16,5 °Brix. As bagas demonstraram ser a parte morfológica com teor de humidade mais elevado. A análise do perfil fenólico por HPLC-DAD-ESI/MSn, no modo negativo, dos extractos metanólicos mostrou que as folhas apresentam maior conteúdo de compostos fenólicos, comparativamente às bagas. Os ácidos hidroxicinâmicos (derivados dos ácidos cafeicos, cumárico e ferúlico), os ácidos cafeoilquínicos, bem como os flavonóis-O-glicosilados (derivados da quercetina e canferol) predominam nestas espécies. A análise pelo modo positivo permitiu a identificação de antocianinas glicosiladas (delfinidina, cianidina, petunidina, peonidina e malvidina) nas bagas e folhas jovens da espécie Vaccinium padifolium. Os ensaios in vitro de simulação da digestão gastrointestinal permitiram compreender a sua influência na actividade antioxidante dos extractos. Após a digestão, as folhas continuam a apresentar maior capacidade antioxidante do que as bagas. Adicionalmente, concluiu-se que as enzimas presentes neste processo têm menor influência do que o pH e a força iónica dos sucos digestivos. O estudo do efeito inibitório in vitro dos extractos sobre a actividade de enzimas responsáveis pelo metabolismo dos hidratos de carbono permitiu determinar que os viii Joana Pinto (2016) extractos foram mais eficientes na inibição da actividade da α-glucosidase do que na inibição da actividade da α-amilase.
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Mestrado em Engenharia Agronómica - Especialização em Proteção das plantas - Instituto Superior de Agronomia - UL
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O lodo de esgoto, atendendo as exigências ambientais, apresenta potencial para disposição em solos agrícolas. Sua incorporação altera as propriedades químicas, físicas e biológicas do solo, pois é rico em macro e micronutrientes e matéria orgânica. Estas alterações podem proporcionar benefícios como aumento da disponibilidade de nutrientes às culturas, indução de supressividade a fitopatógenos habitantes do solo e de resistência às doenças da par te aérea. Por outro lado, pode influenciar negat ivamente o equilíbrio biológico e químico no solo, devido à presença de contaminantes. O objetivo do trabalho foi avaliar os efeitos da incorporação de lodo de esgoto ao solo sobre a severidade de oídio (Erysiphe diffusa) e na supressividade a Rhizoctonia solani e a Macrophomina phaseolina da soja (Glycine max) . Para tanto, foram ut i l izados solos que receberam quat ro aplicações (1999 a 2001) sucessivas de lodos de esgoto originários das Estações de Tratamento de Esgoto de Barueri e de Franca, SP, nas concent rações de 0, 1, 2, 4 e 8 vezes (0N a 8N) a dose de N recomendada para a cultura do milho. Os estudos com oídio foram real izados em casa de vegetação com inoculação natural em dois cultivos sucessivos de soja. Também foi estudado o efeito de substrato produzido com 0%, 2,5%, 5% 10%, 15% e 20% de lodo de Franca sobre a emergência de plântulas e sobre a severidade de oídio da soja em três e dois ciclos, respectivamente. Nos estudos com R. solani e M. phaseol ina, os solos foram ar t i ficialmente infestados com os patógenos e posteriormente cultivados com soja por dois ciclos, sendo avaliado o tombamento e a severidade das doenças. A aplicação de lodo de esgoto no solo aumentou a atividade eliciadora de fitoalexinas em soja e a sever idade do oídio foi inversamente proporcional às concentrações do lodo, tanto no estudo com o solo de campo, como com o subst rato obt ido com o lodo de Franca. A emergência das plântulas de soja, nos três cultivos, foi inversamente proporcional à concent ração do lodo de Franca, sendo totalmente inibida na concent ração de 20%. Nos estudos com R. solani não foram observados efeitos da apl icação do lodo da ETE de Franca sobre o tombamento e a sever idade. No pr imei ro cul t ivo a resposta ao tombamento foi quadrática para o lodo Barueri , sendo que ocorreu aumento nas concentrações de 1N e 2N, e redução na concentração 4N. No segundo cultivo ocorreu aumento nos índices de tombamento de plantas em relação ao primeiro, com resposta quadrática para o lodo Barueri, mas com ponto de inflexão mínimo na concentração de 1N, sendo que para a concentração 8N o tombamento foi semelhante à testemunha. A severidade da doença no colo das plantas manteve a mesma resposta quadrática para o lodo de Barueri nos dois cultivos, com ponto de máximo na dose 4N. Para M. phaseolina a incidência da doença foi inversamente proporcional à concent ração do lodo de Franca. Dessa forma, os resultados não permitem conclusão sobre a indução de supressividade à R. solani e M. phaseolina.
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O objetivo deste trabalho foi avaliar o desempenho agronômico em termos de produtividade e características de frutos em 32 genótipos de melancia. O ensaio foi conduzido na Embrapa Semi-Árido, em Petrolina-PE, durante o período de agosto a outubro de 2005, utilizando o delineamento experimental de blocos ao acaso, com quatro repetições e parcelas com 10 plantas. As mudas foram transplantadas para o campo no espaçamento de 3 x 0,8 m. A cv ?C. Sweet? e as 31 linhas originadas do cruzamento entre ?C. Sweet? e ?CPATSA 85-030? foram avaliadas quanto a rendimento e aspectos externos e internos dos frutos. Verificou-se alto rendimento dos genótipos (33,6 a 66,7 t/ha). Na maioria das linhas, predominaram os frutos com casca rajada, com listras verde-claras alternadas com verde-escuras (96,8%), polpa vermelha (83,9%), alto teor de sólidos solúveis (10 a 12,3o Brix) (93,5%), frutos grandes (8,60 a 11,70 kg) (54,8%) e formato arredondado. Algumas linhas (9,7%) apresentaram alta prolificidade (2,9 a 2,5 frutos/planta), frutos pequenos e arredondados (4,30 a 4,60 kg) e casca rajada verde escura (3,2%). Entre os genótipos de melancia, 05.1168.003, 05.1172.004, 05.1185.001, 05.1189.003, 05.1203.007/1, 05.1194.001/1, 05.1194.005 e 05.1194.006 foram os mais promissores para a obtenção de cultivares resistentes ao oídio e com padrões de frutos para os mercados interno e externo.
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2009
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2009