Mostrando recursos 1 - 20 de 1.144

  1. Utilización de reservas en fructificación en el mandarino "Fortune". Influencia de las técnicas de cuajado

    Duarte, Amílcar; Guardiola, J. L.
    The utilization of reserves in fruiting in the "Fortune" mandarin. The influence of fruit set techniques.The effects on fruit set of GA3, BA, and NAA applications, and that of girdling, has been determined in relation to the mobilization of the reserves during flowring and June drop.Under the conditions of this experiment, performed with high flowering trees, carbohydrate and nitrogen contents in the leaves during flowering and fruitlet abscision were lower than the content found in other cultivars. We could not establish a relationship between metabolite availability and fruit set. Girdling was the only effective fruit set treatment. It had no...

  2. Strategies of attack and defence in woody plant-Phytophthora interactions

    Oßwald, W.; Fleischmann, F.; Rigling, D.; Coelho, A. C.; Cravador, A.; Diez, J.; Dalio, R. J.; Horta Jung, M.; Pfanz, H.; Robin, C.; Sipos, G.; Solla, A.; Cech, T.; Chambery, A.; Diamandis, S.; Hansen, E.; Jung, T.; Orlikowski, L. B.; Parke, J.; Prospero, S.; Werres, S.; Vannini, A.
    This review comprises both well-known and recently described Phytophthora species and concentrates on Phytophthora–woody plant interactions. First, comprehensive data on infection strategies are presented which were the basis for three models that explain invasion and spread of Phytophthora pathogens in different woody host plants. The first model describes infection of roots, the second concentrates on invasion of the trunk, and the last one summarizes infection and invasion of host plants via leaves. On the basis of morphological, physiological, biochemical and molecular data, scenarios are suggested which explain the sequences of reactions that occur in susceptible and tolerant plants following infections...

  3. Nothophytophthora gen. nov., a new sister genus of Phytophthora from natural and semi-natural ecosystem

    Jung, T.; Scanu, B.; Bakonyi, J.; Seress, D.; Kovács, G.M.; Durán, A.; Sanfuentes von Stowasser, E.; Schena, L.; Mosca, S.; Thu, P.Q.; Nguyen, C.M.; Fajardo, S.; González, M.; Pérez-Sierra, A.; Rees, H.; Cravador, A.; Maia, C.; Horta Jung, M.
    During various surveys of Phytophthora diversity in Europe, Chile and Vietnam slow growing oomycete isolates were obtained from rhizosphere soil samples and small streams in natural and planted forest stands. Phylogenetic analyses of sequences from the nuclear ITS, LSU, β-tubulin and HSP90 loci and the mitochondrial cox1 and NADH1 genes revealed they belong to six new species of a new genus, officially described here as Nothophytophthora gen. nov., which clustered as sister group to Phytophthora. Nothophytophthora species share numerous morphological characters with Phytophthora: persistent (all Nothophytophthora spp.) and caducous (N. caduca, N. chlamydospora, N. valdiviana, N. vietnamensis) sporangia with variable shapes, internal differentiation of zoospores and internal,...

  4. De novo assembly of Phlomis purpurea after challenging with Phytophthora cinnamomi

    Baldé, Aladje; Neves, Dina; García-Breijo, Francisco J; Pais, Maria S; Cravador, A.
    Background Phlomis plants are a source of biological active substances with potential applications in the control of phytopathogens. Phlomis purpurea (Lamiaceae) is autochthonous of southern Iberian Peninsula and Morocco and was found to be resistant to Phytophthora cinnamomi. Phlomis purpurea has revealed antagonistic effect in the rhizosphere of Quercus suber and Q. ilex against P. cinnamomi. Phlomis purpurea roots produce bioactive compounds exhibiting antitumor and anti-Phytophthora activities with potential to protect susceptible plants. Although these important capacities of P. purpurea have been demonstrated, there is no transcriptomic or genomic information available in public databases that could bring insights on...

  5. Identification of asymptomatic plants infected with Citrus tristeza virus from a time series of leaf spectral characteristics

    Afonso, Andreia M.; Guerra, Rui; Cavaco, Ana M.; Pinto, Patrícia; Andrade, André; Duarte, Amílcar; Power, Deborah; Marques, Natália T.
    Citrus tristeza virus (CTV) affects citrus crops with differing severity, depending on the viral strain, the citrus cultivar and the scion/rootstock combinations. In this study we address the problem of identifying asymptomatic infected plants using reflectance spectra of the leaves in the visible/near infrared region. Sixteen young citrus plants (8 Citrus clementina hort. ex Tanaka ‘Fina’ and 8 Citrus sinensis (L.) Osbeck ‘Valencia Late’) were split into control and T318 A isolate infected groups. Measurements of reflectance in the 400–1100 nm range, in two leaves per plant, were performed monthly over 6 months and the presence of the virus was confirmed by IC/RT-PCR and real-time PCR....

  6. On the functions generated by the general purpose analog computer

    Olivier, Bournez; Daniel, Graça; Amaury, Pouly
    Preprint

  7. Polynomial Time Corresponds to Solutions of Polynomial Ordinary Differential Equations of Polynomial Length

    Olivier, Bournez; Daniel, Graça; Amaury, Pouly
    The outcomes of this article are twofold. Implicit complexity. We provide an implicit characterization of polynomial time computation in terms of ordinary differential equations: we characterize the class P of languages computable in polynomial time in terms of differential equations with polynomial right-hand side. This result gives a purely continuous elegant and simple characterization of P. We believe it is the first time complexity classes are characterized using only ordinary differential equations. Our characterization extends to functions computable in polynomial time over the reals in the sense of Computable Analysis. Our results may provide a new perspective on classical complexity, by giving...

  8. Polynomial Time Corresponds to Solutions of Polynomial Ordinary Differential Equations of Polynomial Length

    Olivier, Bournez; Daniel, Graça; Amaury, Pouly
    The outcomes of this article are twofold. Implicit complexity. We provide an implicit characterization of polynomial time computation in terms of ordinary differential equations: we characterize the class P of languages computable in polynomial time in terms of differential equations with polynomial right-hand side. This result gives a purely continuous elegant and simple characterization of P. We believe it is the first time complexity classes are characterized using only ordinary differential equations. Our characterization extends to functions computable in polynomial time over the reals in the sense of Computable Analysis. Our results may provide a new perspective on classical complexity, by giving...

  9. Polynomial time corresponds to solutions of polynomial ordinary differential equations of polynomial length

    Olivier, Bournez; Daniel, Graça; Amaury, Pouly
    The outcomes of this article are twofold. Implicit complexity. We provide an implicit characterization of polynomial time computation in terms of ordinary differential equations: we characterize the class P of languages computable in polynomial time in terms of differential equations with polynomial right-hand side. This result gives a purely continuous elegant and simple characterization of P. We believe it is the first time complexity classes are characterized using only ordinary differential equations. Our characterization extends to functions computable in polynomial time over the reals in the sense of Computable Analysis. Our results may provide a new perspective on classical complexity, by giving...

  10. Identification of asymptomatic plants infected with Citrus tristeza virus from a time series of leaf spectral characteristics

    Afonso, Andreia; Guerra, Rui; Cavaco, Ana M.; Pinto, Patrícia; Andrade, André; Duarte, Amílcar; Power, Deborah; Marques, Natália T.
    Citrus tristeza virus (CTV) affects citrus crops with differing severity, depending on the viral strain, the citrus cultivar and the scion/rootstock combinations. In this study we address the problem of identifying asymptomatic infected plants using reflectance spectra of the leaves in the visible/near infrared region. Sixteen young citrus plants (8 Citrus x clementina hort. ex Tanaka ‘Fina’ and 8 Citrus sinensis (L.) Osbeck ‘Valencia Late’) were split into control and T318A isolate infected groups. Measurements of reflectance in the 400-1100 nm range, in two leaves per plant, were performed monthly over 6 months and the presence of the virus was...

  11. Identification of asymptomatic plants infected with Citrus tristeza virus from a time series of leaf spectral characteristics

    Afonso, Andreia; Guerra, Rui; Cavaco, Ana M.; Pinto, Patrícia; Andrade, André; Duarte, Amílcar; Power, Deborah; Marques, Natália T.
    Citrus tristeza virus (CTV) affects citrus crops with differing severity, depending on the viral strain, the citrus cultivar and the scion/rootstock combinations. In this study we address the problem of identifying asymptomatic infected plants using reflectance spectra of the leaves in the visible/near infrared region. Sixteen young citrus plants (8 Citrus x clementina hort. ex Tanaka ‘Fina’ and 8 Citrus sinensis (L.) Osbeck ‘Valencia Late’) were split into control and T318A isolate infected groups. Measurements of reflectance in the 400-1100 nm range, in two leaves per plant, were performed monthly over 6 months and the presence of the virus was...

  12. A situação atual da citricultura na Flórida

    Duarte, Amílcar
    No passado dia 25 de maio, no auditório da Caixa de Crédito Agrícola, em Algoz, teve lugar uma palestra com o título “A situação atual da citricultura na Flórida”, inserida no ciclo de seminários associado ao mestrado em Hortofruticultura da Universidade do Algarve. A palestra foi proferida por Thomas Stopyra, um prestigiado agrónomo americano que trabalha na empresa The Packers of Indian River, Ltd., especializada na produção de toranja para consumo em fresco. A palestra teve como tema central os problemas fitossanitários que têm afetado a citricultura da Flórida, nomeadamente, o cancro cítrico e, mais recentemente, o Huanglongbing (HLB ou greening). No caso do cancro cítrico, houve uma tentativa inicial de eliminação de todas as...

  13. A situação atual da citricultura na Flórida

    Duarte, Amílcar
    No passado dia 25 de maio, no auditório da Caixa de Crédito Agrícola, em Algoz, teve lugar uma palestra com o título “A situação atual da citricultura na Flórida”, inserida no ciclo de seminários associado ao mestrado em Hortofruticultura da Universidade do Algarve. A palestra foi proferida por Thomas Stopyra, um prestigiado agrónomo americano que trabalha na empresa The Packers of Indian River, Ltd., especializada na produção de toranja para consumo em fresco. A palestra teve como tema central os problemas fitossanitários que têm afetado a citricultura da Flórida, nomeadamente, o cancro cítrico e, mais recentemente, o Huanglongbing (HLB ou greening). No caso do cancro cítrico, houve uma tentativa inicial de eliminação de todas as...

  14. Cationic polyene phospholipids as DNA carriers for ocular gene therapy

    Machado, Susana; Calado, Sofia; Bitoque, Diogo; Oliveira, Ana Vanessa; Øpstad, Christer L.; Zeeshan, Muhammad; Sliwka, Hans-Richard; Partali, Vassilia; Pungente, Michael D.; Silva, Gabriela
    Recent success in the treatment of congenital blindness demonstrates the potential of ocular gene therapy as a therapeutic approach. The eye is a good target due to its small size, minimal diffusion of therapeutic agent to the systemic circulation, and low immune and inflammatory responses. Currently, most approaches are based on viral vectors, but efforts continue towards the synthesis and evaluation of new nonviral carriers to improve nucleic acid delivery. Our objective is to evaluate the efficiency of novel cationic retinoic and carotenoic glycol phospholipids, designated C20-18, C20-20, and C30-20, to deliver DNA to human retinal pigmented epithelium (RPE) cells....

  15. Factors affecting rind pitting in the mandarin hybrids "fortune" and "nova". The influence of exogenous growth regulators

    Duarte, Amílcar; Guardiola, J. L.
    The commercialization of the mandarin hybrids "Fortune" and "Nova" is hindered by the development of cold-induced pitting in the fruit rind which may develop either in the orchard or during storage and transport. In the late cropping cultivar "Fortune", the pitting develops on tree during the winter months and affects mainly the exposed fruit from the north-west quadrant of the tree. The induction of symptoms under uniform conditions in the cold-room reveals differences in the susceptibility to chilling injury among the fruits and the fruit sides. The green fruit is not susceptible. Susceptibility develops as pigmentation progresses, and it is higher...

  16. Efficiency of RAFT-synthesized PDMAEMA in gene transfer to the retina

    Bitoque, Diogo B.; Simão, Sónia; Oliveira, Ana V.; Machado, Susana; Duran, Margarita R.; Lopes, Eduardo; Costa, Ana M. Rosa da; Silva, Gabriela
    Gene therapy has long been heralded as the new hope to evolve from symptomatic care of genetic pathologies to a full cure. Recent successes in using gene therapy for treating several ocular and haematopoietic pathologies have shown the great potential of this approach that, in the early days, relied on the use of viral vectors, which were considered by many to be undesirable for human treatment. Therefore, there is considerable interest and effort in developing non-viral vectors, with efficiency close to that of viral vectors. The aim of this study was to develop suitable non-viral carriers for gene therapy to...

  17. Analyzing spatial patterns linked to the ecology of herbivores and their natural enemies in the soil

    Campos-Herrera, Raquel; Ali, J. G.; Diaz, B. M.; Duncan, L. W.
    Modern agricultural systems can benefit from the application of concepts and models from applied ecology. When understood, multitrophic interactions among plants, pests, diseases and their natural enemies can be exploited to increase crop production and reduce undesirable environmental impacts. Although the understanding of subterranean ecology is rudimentary compared to the perspective aboveground, technologies today vastly reduce traditional obstacles to studying cryptic communities. Here we emphasize advantages to integrating as much as possible the use of these methods in order to leverage the information gained from studying communities of soil organisms. PCR-based approaches to identify and quantify species (real time qPCR...

  18. The abundance, diversity, and metabolic footprint of soil nematodes is highest in high elevation alpine grasslands

    Kergunteuil, Alan; Campos-Herrera, Raquel; Sánchez-Moreno, Sara; Vittoz, Pascal; Rasmann, Sergio
    info:eu-repo/semantics/publishedVersion

  19. Effects of cover crops on the overwintering success of entomopathogenic nematodes and their antagonists

    Jaffuel, Geoffrey; Blanco-Pérez, Rubén; Büchi, Lucie; Mäder, Paul; Fließbach, Andreas; Charles, Raphaël; Degen, Thomas; Turlings, Ted C.J.; Campos-Herrera, Raquel
    Conservation agriculture is arising as an alternative to conventional agriculture with the aim to have a reduced impact on the environment. This includes the use of cover crops to conserve soil quality by limiting soil erosion, adding organic matter, and enhancing soil nutrient content, as well as water availability, which are all factors that can greatly influence the presence of soil organisms. In the current study, we investigated whether winter cover crops can enhance the persistence of entomopathogenic nematodes (EPN) over the winter season. In a first trial we augmented EPN populations in plots without (bared) and with the cover crops, pea (Pisum sativum) or mustard...

  20. Efficacy of Electrolyzed Water to Inactivate Foodborne Pathogens on Fresh-Cut Apples

    Graça, A.; Nunes, C.; Quintas, C.; Abadias, M.; Usall, J.; Salazar, M.
    Chlorine is the most common disinfectant used in the fresh-cut industry but nowadays environmental and health risks have led to the need to find new sanitizers. Electrolyzed water (EW) appears to be a promising alternative. In this work, disinfection efficacy of acidic (AEW) and neutral (NEW) electrolyzed water in fresh-cut apple slices inoculated with Escherichia coli, Listeria innocua or Salmonella choleraesuis was studied. Apple slices were inoculated with a 10(7) cfu/ml suspension of pathogens and treated with the sanitizer EW solutions, with 100 or 50 ppm of free chlorine solutions and with distilled water. Population reduction was determined 30 min...

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