1000 resultados para teores de enxofre


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Lateral shoots of the Aloe vera (L.) Burm. cultivated in vitro, without addition vegetal regulators, for 90 days, were inoculated in MS culture-medium, containing or not spermine and/or spermidine. After 30 days of cultivation, the plants were submitted to biochemical analysis together with micropropagated plants - that were under in vitro cultivation for 90 days - (denominated as characterization), and matrix plants (in vivo). The levels of free polyamines, total phenols, total flavonoids, and the activity of peroxidase were evaluated in the biochemical analyses. The exogenous application of spermidine have promoted large number of shoots. Spermidine and spermine have promoted, when associated, an increase in the number of shoots as well as an increase of the contents of putrescine and and flavonoids. The putrescine has presented the most significant alterations, enabling to be utilized as marker of morphogenesis in the micropropagated Aloe vera. Tissues under active growth have presented high activity of peroxidase as well as those with greater rate of oxidation. In these tissues, there were noticed also higher contents of total flavonoids, indicating the need of antioxidative compounds. The action of polyamines jointly tseemed to be benefic for the shooting of micropropagated Aloe vera.

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This work aimed to compare fertigation to conventional fertilization in a five-year-old 'Valência' orange orchard, irrigated by microsprinklers. The conventional fertilization, using the recommended dosage for the crop, was parceled out in three during the year. In the fertigation treatments a complete dose, 1/2 and 1/3 of the conventional fertilization dose, parceled out in ten in a year, were used. Trunk circumference and leaf volume, leaf chlorophyll content and fruit yield and quality were measured. For the first year, significant differences among the treatments for the evaluated parameters were not observed; however, it was noticed that fertigation treatments caused less nutritional unbalance, obtained by DRIS. The fertigation treatment using half dosage showed the best result regarding to fruit yield and quality.

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A better understanding of the differences between the levels of nutrients, depending on the type of pruning used in the cultivation of the guava tree, may allow a more adequate understanding of the physiological processes of this fruit. The analysis of flowers is a tool that can be used to assist in assessing the nutritional status of crops, especially perennials. We evaluated the effects of different types of pruning on nutrient concentrations in flowers and fruit, at different developmental stages and in different parts of the fruit. The study was carried out in Vista Alegre do Alto, in orchards of guava variety Paluma. Flowers and fruit were collected in orchards, one under heavy pruning and the other with continuous pruning. The fruit were collected in two stages (two millimeters length and mature) and divided into basal part and apex, with the top toward the stalk. Flowers were collected in the same orchards as the fruits, sampling the basal part and apex of the flowers. F tests were performed and, when necessary, the Scott-Knott test at α= 5%. Overall, there were nutritional differences among flowers and fruits in relation to the type of pruning employed; drastic pruning provided higher levels of nutrients compared with continuous pruning. In relation to the portion of the samples, especially for fruit, there were differences between the apex and base, as well as between different stages of fruit collection.

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Were analyzed 29 samples, 16 wet and 13 dry cat food of different flavors. The iodine levels ranged from 2.7 to 3.4 (average 2.95 mg/kg/MS) in dry food and 2.9 to 4.0 (average 3.4 mg/kg/MS) in the wet food. Eight samples (27.6%) specified on the package the assurance level (maximum) of iodine, with a dry (2.0 mg/kg/diet) and seven wet (0.04 mg/kg/diet). All non-compliant, because the values were higher than declared. Cats fed commercial diets consume proportionally more iodine in wet food than cats fed dry diets, but both with high levels of iodine. All samples analyzed were above the amounts stated on the labels. Accordingly, the wet and dry commercial food for cats show no reliable values with those reported, resulting in a possible excessive intake of this trace element for animals in question.

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This paper proposes a didactic experience on the simulation of the atmospheric corrosion of copper and zinc due to the presence of sulfur and nitrogen oxides. Quantitative parameters of corrosion such as gain and loss of mass were determined to assess the variation of the layer thickness of the metal and of the corrosion products. This proposal aims a better understanding of some basic aspects of acid rain formation using fundamental concepts of chemistry such as the reactivity of gases.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Ciência Animal - FMVA

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Cirurgia Veterinária - FCAV

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)