789 research outputs found

    Algoritmo computacional para determinar o perfil mínimo de marcadores moleculares que discriminam um conjunto de cultivares.

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    Alterações do teor de nitrogênio na folha e pecíolo, na produção e composição da uva pela adubação nitrogenada em videiras no Planalto do Rio Grande do Sul.

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    O trabalho objetivou avaliar como a aplicação de N afeta o seu teor na folha inteira e pecíolo, usados para a recomendação de N à videira no RS e SC, e sobre a produção e composição da uva.bitstream/CNPUV/10104/1/cot087.pd

    Grape yield and must composition of "Cabernet Sauvignon" grapevines with organic compost and urea fertilization.

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    Urea and organic compost are applied as a nitrogen (N) source in vineyards. The aim of this study was to evaluate the yield, total N content in the leaves and the must composition in grapevines with the application of organic compost and urea. ?Cabernet Sauvignon? grapevines, in the 2008/2009 and 2009/2010 crop seasons were subjected to the application of 40 kg N ha-1 in the form of organic compost and urea; but there were also unfertilized grapevines. In both crop seasons, leaves were collected at the stages of full flowering and at the change in color of the berries, and the total N content were analyzed; grape yield was evaluated and enological attributes were determined in the must. The application of organic compost and urea did not affect the N content in the leaf nor the grape yield in the second crop season evaluated. However, in the first crop season, grape yield was greater in the grapevines with application of organic compost to the soil. The addition of N sources did not affect the total nutrient content in the must but, in the second crop season, the grape must from the grapevines with the addition of organic compost had a lower soluble solids concentration and a higher total acidity value, as well as tartaric and malic acid values. KEYWORDS: nitrogen, leaf analysis, Vitis vinifera L

    Soil phosphorus fractions in a sandy typic hapludaft as affected by phosphorus fertilization and grapevine cultivation period.

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    The purpose of this study was to quantify the phosphorus (P) fractions in phosphate-fertilized sandy soils under grapevines. Soil was sampled from a grassland site and two vineyards (13 and 31 years old) in the State Rio Grande do Sul, Brazil, from the layers 0-5, 5-10, 10-15, 15-20, and 20-40 cm deep. The samples were prepared and P fractions were assessed by chemical fractionation. Phosphate fertilization of the vineyard soils increased P contents to a depth of 40 cm, especially in the more recalcitrant fractions but detectable in the more labile fractions as well, which are plant available and may increase the risk of environmental contamination. Phosphate fertilizers and the period of grapevine cultivation had little effect on the levels of organic P forms, whereas cover crops in vineyards could be an appropriate strategy to increase or maintain the levels of soil organic matter and the levels of organic P over the years

    Association of the mtDNA m.4171C>A/MT-ND1 mutation with both optic neuropathy and bilateral brainstem lesions

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    Background: An increasing number of mitochondrial DNA (mtDNA) mutations, mainly in complex I genes, have been associated with variably overlapping phenotypes of Leber’s hereditary optic neuropathy (LHON), mitochondrial encephalomyopathy with stroke-like episodes (MELAS) and Leigh syndrome (LS). We here describe the first case in which the m.4171C>A/MT-ND1 mutation, previously reported only in association with LHON, leads also to a Leigh-like phenotype. Case presentation: A 16-year-old male suffered subacute visual loss and recurrent vomiting and vertigo associated with bilateral brainstem lesions affecting the vestibular nuclei. His mother and one sister also presented subacute visual loss compatible with LHON. Sequencing of the entire mtDNA revealed the homoplasmic m.4171C>A/MT-ND1 mutation, previously associated with pure LHON, on a haplogroup H background. Three additional non-synonymous homoplasmic transitions affecting ND2 (m.4705T>C/MT-ND2 and m.5263C>T/MT-ND2) and ND6 (m.14180T>C/MT-ND6) subunits, well recognized as polymorphisms in other mtDNA haplogroups but never found on the haplogroup H background, were also present. Conclusion: This case widens the phenotypic expression of the rare m.4171C>A/MT-ND1 LHON mutation, which may also lead to Leigh-like brainstem lesions, and indicates that the co-occurrence of other ND non-synonymous variants, found outside of their usual mtDNA backgrounds, may have increased the pathogenic potential of the primary LHON mutation

    Do cover crops compete with young grapevines for fertilizer nitrogen?

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    Vineyard soils of the Campanha Gaúcha region of Rio Grande do Sul are sandy and have low to medium organic matter content, displaying low natural ability to supply nitrogen (N). Therefore, maintenance of cover crops is essential or the protection of the soil surface from the impact of raindrops and water erosion. The application of nitrogen fertilizers is also necessary. However, cover crops can absorb part of the nitrogen applied in the soil, decreasing the availability to young vines, which may slow the growth of root and shoot, and thus, the beginning of grape production

    Iron fertilization to enhance tolerance mechanisms to copper toxicityof ryegrass plants used as cover crop in vineyards.

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    Ryegrass (Lolium perenneL.) is a plant species that can express mechanisms of tolerance to copper (Cu)toxicity. Therefore, the agronomical approach of intercropping system with ryegrass may represent apromising tool to limit the onset of Cu toxicity symptoms in the other intercropped plants species,particularly when an inadequate nutrient availability like iron (Fe) shortage is also concurrently present.This study aimed at assessing the mechanisms involved in the mitigation of Cu phytotoxicity and thestress effects on plant growth, root morphology and nutrition of ryegrass fertilized with two different Fesources. To this purpose, seedlings of ryegrass were hydroponically grown for 14 days in controlledconditions with 4 different levels of Cu (0.2, 5.0, 25 and 50mM) and with either 100mM Fe-EDDHA or Fe-EDTA. Results show that high levels of Cu availability enhanced the root content of organic anions as wellas the root exudation. Different Fe fertilizations at the condition of 50mM Cu induced changes in rootphenolic compounds, citrate and fumarate contents and the exudation pattern of phenolic compounds.Differences in plant growth were not observed between the two Fe sources, although Cu concentration inplant tissue fed with Fe-EDTA was lower in the condition of 50mM Cu. The enhanced root exudation ofCu-complexing organic compounds (including phenolics) in ryegrass plants when exposed to excessiveCu availability could be at the basis of the ameliorated edaphic rhizosphere conditions (lower Cuavailability). For this reason, from the agronomical point of view ryegrass plants used in intercroppingsystems with crops like vine plants could represent a promising strategy to control Cu toxicity invineyard soils. Further studies under thefield conditions must be taken to support presentfindings.©2019 Elsevier Ltd. All rights reserved

    Acúmulo de fósforo em solos cultivados com videiras na região da Campanha Gaúcha.

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    O presente trabalho teve como objetivo avaliar o acúmulo de frações de P em solos cultivados com videiras e com histórico de aplicação de fertilizantes fosfatados na região da Campanha Gaúcha do RS.bitstream/item/73780/1/Comunicado-Tecnico-131.pd

    Lixiviação e volatilização de nitrogênio em um Argissolo cultivado com videira submetida à adubação nitrogenada.

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    O nitrogênio (N) aplicado na superfície do solo em vinhedos pode ser perdido por volatilização ou lixiviação, sendo uma das possíveis explicações para o baixo aproveitamento de N pelas videiras. O trabalho objetivou avaliar as perdas de N por volatilização e lixiviação do N mineral em solo cultivado com videira submetida à adubação nitrogenada. Foram instalados dois experimentos em um vinhedo de Cabernet Sauvignon, em Rosário do Sul (RS), Brasil. No experimento 1, foram instalados lisímetros no solo que recebeu a aplicação de 0, 40, 80 e 120kg de N ha-1 ano-1 na forma de ureia e, durante o período de agosto a dezembro de 2009, foi coletada a solução do solo para a análise de N mineral. No experimento 2, foram instaladas câmaras coletoras no solo que recebeu, em agosto de 2010, a aplicação de 0, 20, 40, e 80kg de N ha-1 ano-1 na forma de ureia, 40kg de N ha-1 ano-1 de composto orgânico e 40kg de N ha-1 ano-1 de ureia revestida com polímeros, para avaliar a volatilização de N-NH3 do momento da aplicação até 80 horas depois da aplicação. As maiores concentrações de nitrogênio mineral na solução lixiviada foram encontradas nas doses mais elevadas de fertilizante mineral aplicado e ao longo da brotação e florescimento das videiras, o que pode diminuir o aproveitamento do nutriente pelas plantas. Os maiores fluxos e perdas de amônia do solo cultivado com videira para a atmosfera aconteceram nas doses mais elevadas de nitrogênio mineral aplicado, especialmente, depois de 44 horas da sua aplicação sobre a superfície do solo. A aplicação de ureia revestida com polímeros e composto orgânico promoveram as menores perdas de amônia por volatilização, o que pode estimular o aproveitamento de nitrogênio pelas videiras
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