Biblioteca Digital

Laser induced breakdown spectroscopy (LIBS) has been evaluated for the determination of micronutrients (B, Cu, Fe, Mn and Zn) in pellets of plant materials, using NIST, BCR and GBW biological certified reference materials for analytical calibration. Pellets of approximately 2 mm thick and 15 mm diameter were prepared by transferring 0.5 g of powdered material to a 15 mm die set and applying 8.0 tons cm(-2). An experimental setup was designed by using a Nd:YAG laser operating at 1064 nm (200 mJ per pulse, 10 Hz) and an Echelle spectrometer with ICCD detector. Repeatability precision varied from 4 to 30% from measurements obtained in 10 different positions (8 laser shots per test portion) in the same sample pellet. Limits of detection were appropriate for routine analysis of plant materials and were 2.2 mg kg(-1) B, 3.0 mg kg(-1) Cu, 3.6 mg kg(-1) Fe, 1.8 mg kg(-1) Mn and 1.2 mg kg(-1) Zn. Analysis of different plant samples were carried out by LIBS and results were compared with those obtained by ICP OES after wet acid decomposition. (C) 2009 Elsevier B.V. All rights reserved.; Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[04/15965-2]; Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[06/06466-8]; Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[05/50773-0]; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)[477385/2006-0]; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)[301285/2006-3]

A produtividade de uma lavoura de soja representa apenas, aproximadamente, 20% do potencial genético. Dessa forma, a exploração das características genéticas tem sido alvo dos pesquisadores para incrementar a produtividade da cultura. Dentro disso, a potencialização fisiológica pela aplicação de estimulantes biológicos, desde a germinação das sementes até a fase reprodutiva da cultura, tem sido uma das principais estratégias adotadas. Visando um aporte à pesquisa nas respostas fisiológicas da cultura, objetivou-se avaliar os efeitos fisiológicos do tratamento de sementes e aplicações foliares de micronutrientes, hormônios e aminoácidos e o quanto estes representam na produção em sistemas de alta produtividade. Foram realizados dois experimentos, sendo um em casa de vegetação (condições parcialmente controladas) (Experimento I) e outro a campo (Experimento II) no Centro Universitário de Patos de Minas (UNIPAM), Patos de Minas-MG, durante o período de janeiro a maio de 2013. Foram realizadas avaliações bioquímicas (atividade das enzimas nitrato redutase, urease, catalase, peroxidase e superóxido dismutase, peroxidação de lipídios e teor de prolina), fisiológicas (fotossíntese liquida) e fenométricas (emergência...

A nutrição mineral representa um dos principais fatores de produção na cultura da cana-de-açúcar, tendo impacto direto na produtividade, na qualidade, e nos custos de produção. A expansão da cultura sobre área de baixa fertilidade natural ou ainda em áreas tradicionais de cultivo com evidente esgotamento dos recursos, reforça a necessidade da aplicação de fertilizantes na recuperação da produtividade, principalmente em áreas de soqueira de cana. O fósforo é um elemento chave nesse processo dada a intensidade das reações de adsorção e fixação, que o tornam pouco disponível para a cultura. Além disso o fato de ser normalmente aplicado na reforma do canavial, não garante o correto fornecimento do mesmo nos ciclos consecutivos de soca. Já os micronutrientes representam um desafio, uma vez que mesmo em áreas deficientes, as resposta não são conclusivas. Neste contexto, o objetivo deste trabalho foi avaliar a eficiência de fertilizantes fosfatos aplicados no solo e micronutrientes aplicados via foliar sobre a produtividade e qualidade tecnológica em soqueira de cana-de-açúcar. Para tanto, foi instalado um experimento no município de Porto Ferreira(SP) na Usina Ferrari S/A, em dezembro de 2010, sob Latossolo Vermelho-Amarelo Distrófico de textura média...

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); A method for determination of B, Ca, Cu, Fe, K, Mg, Mn, Mo, P. S and Zn in plant tissues by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) is proposed. This method is based on special features of HR-CS-AAS, such as side pixel registration, wavelength integrated absorbance, and molecular absorption bands, for determining macro- and micronutrients in foliar analysis without requiring several different strategies for sample preparation and adjustment of the analytes concentration ranges. Plant samples were analyzed and results for certified materials were in agreement at a 95% confidence level (paired t-test) with reference values. Recoveries of analytes added to plant digests varied within the 82-112% interval. Relative standard deviations (n = 12) were lower than or equal to 5.7% for all analytes in all concentration ranges. (C) 2010 Elsevier B.V. All rights reserved.

The objective of this work was to investigate the adsorption of micronutrients in humin and to verify the ability to release these elements in water. The first step was to determine the adsorption capacity of humin for several essential plant micronutrients and check the kinetic parameters. The order of adsorption was Zn < Ni < Co < Mn < Mo < Cu < Fe, whereas Zn showed maximum values of ca. 2.5 mg g-1 and Fe values of ca. 0.5 mg g-1 for systems containing 1 g of humin. Iron presented higher percentages of release (ca. 100%) and Co the lowest percentages (0.14%). The findings suggested that the use of humin enriched with micronutrients can be a promising alternative for the fertilization of agricultural soils, with the additional benefit of incorporating organic matter present in the form of humic substances into the soil and improving the agricultural productivity. © 2013 Sociedade Brasileira de Química.

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Processo FAPESP: 10/12210-1; The objective of this work was to evaluate the adsorption and desorption of micronutrients in tropical peats, from the perspective of potential agricultural applications. Adsorption experiments were performed at different pH values, using solutions containing individual and multiple metal ions. Maximum adsorption capacity occurred at pH 6.0, and the order of affinity was Cu > Fe > Co > Ni > Zn = Mn. Release of the micronutrients was evaluated at different pH values, using an aqueous medium as well as soil and plants. Release of the micronutrients was most efficient at pH 6.0, and followed the order: Fe > Zn > Mn > Co = Ni > Cu. Micronutrient release to the soil was accompanied by uptake by the plant. The use of tropical peat enriched with micronutrients could contribute to improved agricultural productivity, since the release profile of the micronutrients can effectively stimulate plant growth.

The objective of this work was to investigate the adsorption of micronutrients in humin and to verify the ability to release these elements in water. The first step was to determine the adsorption capacity of humin for several essential plant micronutrients and check the kinetic parameters. The order of adsorption was Zn < Ni < Co < Mn < Mo < Cu < Fe, whereas Zn showed maximum values of ca. 2.5 mg g-1 and Fe values of ca. 0.5 mg g-1 for systems containing 1 g of humin. Iron presented higher percentages of release (ca. 100%) and Co the lowest percentages (0.14%). The findings suggested that the use of humin enriched with micronutrients can be a promising alternative for the fertilization of agricultural soils, with the additional benefit of incorporating organic matter present in the form of humic substances into the soil and improving the agricultural productivity.

The objective of this work was to evaluate the adsorption and desorption of micronutrients in tropical peats, from the perspective of potential agricultural applications. Adsorption experiments were performed at different pH values, using solutions containing individual and multiple metal ions. Maximum adsorption capacity occurred at pH 6.0, and the order of affinity was Cu > Fe > Co > Ni > Zn = Mn. Release of the micronutrients was evaluated at different pH values, using an aqueous medium as well as soil and plants. Release of the micronutrients was most efficient at pH 6.0, and followed the order: Fe > Zn > Mn > Co = Ni > Cu. Micronutrient release to the soil was accompanied by uptake by the plant. The use of tropical peat enriched with micronutrients could contribute to improved agricultural productivity, since the release profile of the micronutrients can effectively stimulate plant growth.

There is growing evidence that micronutrient intake has a significant effect on the toxicity and carcinogenesis caused by various chemicals. This paper examines the effect of micronutrient status on the toxicity of four nonessential metals: cadmium, lead, mercury, and arsenic. Unfortunately, few studies have directly examined the effect of dietary deficiency or supplementation on metal toxicity. More commonly, the effect of dietary alteration must be deduced from the results of mechanistic studies. We have chosen to separate the effect of micronutrients on toxic metals into three classes: interaction between essential micronutrients and toxic metals during uptake, binding, and excretion; influence of micronutrients on the metabolism of toxic metals; and effect of micronutrients on secondary toxic effects of metals. Based on data from mechanistic studies, the ability of micronutrients to modulate the toxicity of metals is indisputable. Micronutrients interact with toxic metals at several points in the body: absorption and excretion of toxic metals; transport of metals in the body; binding to target proteins; metabolism and sequestration of toxic metals; and finally, in secondary mechanisms of toxicity such as oxidative stress. Therefore...

To establish whether there is new evidence to inform changes to WHO 2003 recommendations for micronutrient intake in persons with HIV/AIDS, we conducted a narrative review of the literature published from 2003 to 2010. Although the review focused on new randomized controlled trials of multiple micronutrients in HIV-infected adults, including pregnant and lactating women, we also considered randomized trials of single micronutrients. The review found that there are few published randomized controlled trials of micronutrients in HIV-infected persons and that most trials used high-dose multiple micronutrient supplementation. The trials were heterogeneous with respect to the composition and dose of micronutrients used and the target population studied. Despite this heterogeneity, 5 of 6 trials that used high-dose multiple micronutrients showed benefits in terms of either improved CD4 cell counts or survival. However, many of these trials were small and of short duration, and therefore the long-term risks and benefits of high-dose multiple micronutrients are not established. The current WHO recommendation for an intake of micronutrients at Recommended Dietary Allowance amounts continues to be a reasonable target for persons with clinically stable HIV infection. In light of new data that show adverse effects of high-dose vitamin A...

The effects of selenium (Se) on plant growth under drought stress and in the presence of micronutrients are yet to be investigated. Hence, in a field experiment in 2007 the effects of Se and micronutrients including iron (Fe), zinc (Zn), copper (Cu), manganese (Mn), boron (B) and molybdenum (Mo) were evaluated on corn (Zea mays L.) grain yield under drought stress. Main- and sub-plots were devoted to irrigation (control and water stressed at the eight-leaf, blister and grain filling stages) and micronutrients treatments, respectively. Micronutrients were foliarly applied at 2 l ha-1 at the six-leaf stage, one week before tasseling, using a corn fertilizer, called biomin containing (on the basis of dry weight percentage) Fe (2.6), Zn (4.1), Cu (1.5), Mn (2.6), B (1.5), Mo (0.5) and Mg (4.1). Se was used as sodium selenite (Na2SeO3), at the rate of 20 g ha-1 two weeks before treating the plants with drought stress. Effects of drought stress on plant growth were determined based on the activity or level of antioxidants. With increasing the stress level, addition of Se or micronutrients significantly enhanced the antioxidant activity and level as well as corn grain yield. The interaction effects between Se and micronutrients adversely affected antioxidant activity as well as corn grain yield. Se addition at the grain filling stage resulted in the highest grain yield under drought stress. The single but not the combined use of Se or micronutrients can alleviate the unfavorable effects of drought stress on corn yield by affecting plant metabolism including antioxidant activity.

The highlands from the southern region of State of Rio Grande do Sul have been traditionally used for extensive cattle raising, which practically does not demand soil analysis and fertilization. The sustainable use of the soils with other agricultural activities, such as forestry, that has been increased in the last few years, needs a more suitable and accurate knowledge of the needs of soil fertilization, including the micronutrients. In this context, this study has the objective of quantifying the micronutrients availability and reserve present in the different types of soils of the region. For this purpose, 22 soil profiles representative of the different soil parent material and profile development found in the region were sampled and chemical analysis of the total, available and oxide bound Cu, Zn, B, Fe and Mn were performed. The results indicate that for the majority of the soils the available and total contents of micronutrients are high, with more likely deficiency possibilities for Cu and B, in this order, related to specific soil parent material types. For Zn and Mn, despite the high available contents, there is the possibility of deficiency in the future due to a low reserve in case the crop withdraw be not returned. The ammonium oxalate extracted Cu and Zn data indicate that the reserve of these micronutrients in low cristallinity Fe (and Mn) is negligible. Only a small fraction of the total Cu is found in oxides in the soils studied...

Nutrition science has evolved into a multidisciplinary field that applies molecular biology and integrates individual health with the epidemiologic investigation of population health. Nutritional genomics studies the functional interaction of food and its components, macro and micronutrients, with the genome at the molecular, cellular, and systemic level. Diet can influence cancer development in several ways, namely direct action of carcinogens in food that can damage DNA, diet components (macro or micronutrients) that can block or induce enzymes involved in activation or deactivation of carcinogenic substances. Moreover, inadequate intake of some molecules involved in DNA synthesis, repair or methylation can influence mutation rate or changes in gene expression. Several studies support the idea that diet can influence the risk of cancer; however information concerning the precise dietary factor that determines human cancer is an ongoing debate. A lot of epidemiological studies, involving food frequency questionnaires, have been developed providing important information concerning diet and cancer, however, diet is a complex composite of various nutrients (macro and micronutrients) and non-nutritive food constituents that makes the search for specific factors almost limitless.

Fundamento: Associações inversas entre a ingestão de micronutrientes e desfechos cardiovasculares foram demonstradas previamente na população geral. Objetivo: Revisar sistematicamente o papel de micronutrientes no desenvolvimento/presença de desfechos cardiovasculares em pacientes com diabetes. Métodos: Foi realizada uma busca nas bases de dados Medline, Embase e Scopus (Janeiro/1949-Março/2012) por estudos observacionais que avaliaram micronutrientes antioxidantes e desfechos cardiovasculares em pacientes com diabetes e, em seguida, os dados foram selecionados e extraídos (dois revisores independentes). Resultados: Dos 15658 estudos identificados, cinco foram incluídos, sendo três de caso-controle e dois de coorte, com um acompanhamento de 7-15 anos. Uma metanálise não foi realizada devido aos diferentes micronutrientes antioxidantes (tipos e métodos de medição) e os desfechos avaliados. Os micronutrientes avaliados foram: vitamina C (dieta e/ou suplementação), cromo e selênio em amostras de unha, e α-tocoferol e zinco no soro. A ingestão de > 300 mg de vitamina C a partir de suplementos esteve associada a um risco aumentado de doença cardiovascular, doença arterial coronariana (DAC) e acidente vascular cerebral (RR 1...

The dynamics of Mn, Fe and Zn has been studiedin the litterfall and in the decomposition process in individual monospecific stands of holm oak (Quercus ilex), beech (Fagus sylvatica) and fir (Abies alba) in the Montseny mountains. Usually, micronutrient concentrations in different litterfall fractions are higher than those in biomass due to the increase in dead organs. Beech is the forest with the highest manganese and iron return in litterfall. It has been observed that the maximum micronutrients concentrations usually coincide with litterfall peaks in each forest. These elements tend to acumulate in some steps of the decomposition process. Fe is the most immobilized nutrient. Mn is more readily released if the pH and wetness conditions are the right ones. In the whole, the three forests have important differences in micronutrient dynamics according to temperature, wetness and structural quality of litterfall fracions.; S'analitza la dinamica del Mn, Fe i Zn en la caiguda de la virosta i durant el procés de descomposició d'un alzinar muntanyenc, una fageda i una avetosa del Montseny. En general, les concentracions de micronutrients en diferents fraccions de la virosta són més elevades que les de la biomassa a causa de I'augment de metalls pesats en els organs morts. La fageda és el bosc que aporta més quantitat de manganes i ferro...

OBJETIVO: abordar a importância dos micronutrientes zinco, ferro e vitamina A no crescimento linear e desenvolvimento infantil. MÉTODO: foram consultadas as bases de dados Medline e LILACS utilizando duas estratégias de busca: i) growth AND zinc AND iron AND vitamin A AND child, preschool OR infant, para o tema micronutrientes e crescimento; e ii) child development AND zinc AND iron AND vitamin A, para o tema micronutrientes e desenvolvimento. Os artigos foram classificados quanto ao tipo de manuscrito e principais resultados. RESULTADOS: foram incluídos 19 artigos referentes ao crescimento e 5 artigos referentes ao desenvolvimento. DISCUSSÃO: considerando as prevalências, sugere-se que as deficiências de ferro e zinco devem contribuir, concurrentemente, com o déficit de estatura. O papel do zinco no sistema hormonal primário justifica ser o nutriente de maior importância no crescimento, afetando a estatura das crianças tanto em estados de deficiência leve como moderada. Evidências fisiológicas e experimentais colocam a importância dos micronutrientes ferro e zinco no desenvolvimento e déficit cognitivo nos primeiros anos da vida. Apesar disso, os resultados ainda não são conclusivos. Pensa-se que o zinco pode limitar processos neuropsicológicos específicos...

De uma plantação bem conduzida de milho doce (Zea mays var. saahirata) cv. Contibrasil situada sobre um Latossolo Vermelho Escuro Orto, série "Luiz de Queiroz" de alta fertilidade natural no município de Piracicaba, SP, foram coletadas plantas aos 45, 60, 75, 90 e 105 dias após a germinação. As plantas foram divididas em folhas novas, velhas, colmo, pendão e espigas. O material após sofrer os processos necessários foi seco, pesado e analisado para N, P, K, Ca, Mg, S, B, Cu, Fe, Mn e Zn por métodos convencionais de laboratório. Os autores concluíram que: aumento de peso de matéria seca total é contínua até o final do ciclo; a acumulação de macronutrientes pela planta inteira obedece a seguinte ordem decrescente: N, K, P,Ca=S e Mg; o maior acúmulo de macronutrientes no final do ciclo ocorre no colmo, com exceção do N que é acumulado em maior quantidade nas espigas; o acúmulo de micronutrientes pela planta inteira obedece a seguinte ordem decrescente: Fe, Mn, Cu, Zn e B; o maior acúmulo de micronutrientes no final do ciclo ocorre no colmo; a exportação de nutrientes pela espiga representa 26,15% do total de nutrientes contidos na plantação.; Growt, yield and nutrient accumulation by sweet corn (Zea mays var. saoharata) cv. Contibrasil was studied in Piracicaba...

Tendo-se como objetivo conhecer o comportamento nutricional da cultura de Gergelim (Sesamum indicum L.), instalou-se um ensaio no campo experimental do Departamento de Agricultura e Horticultura, da Escola Superior de Agricultura "Luiz de Queiroz" da Universidade de São Paulo, visando determinar as concentrações e acúmulo de micronutrientes pelo cultivar Venezuela em diferentes estádios de desenvolvimento, e avaliar a exportação pela colheita. O experimento foi conduzido no decorrer do ano agrícola 1981/1982, num solo Terra Roxa Estruturada, Série Luiz de Queiroz. O delineamento estatístico foi inteiramente casualizado, com um cultivar, oito épocas de amostragem e quatro repetições. As primeiras amostras foram coletadas 28 dias após a emergência das plantulas (desbaste) e as demais em intervalos regulares de 12 dias, de tal maneira que sempre houvessem outras quatro competitivas na fileira. No material coletado (folha, caule e fruto), determinou-se os teores e acúmulo de micronutrientes, com exceção do molibdênio e cloro. Concluiu-se que: - a concentração dos micronutrientes foi sempre maior nas folhas do que nos caules; - a acumulação dos micronutrientes foi sempre maior nas folhas do que nos caules, com exceção do zinco; - a concentração dos micronutrientes nos órgãos amostrados...

Aiming to verify the effects of the use of sources of amino acids associated to micronutrients on the final yield of common bean, was conducted an experiment at FAZU in Uberaba-MG, using Carioca kind of bean, cultivar Pérola. The design was in randomized blocks with eight treatments and four repetitions. The sowing was done in August 18, 2008, the final stand of 240.000 plants ha-1.  Fertilization was held with 8-28-16 and coverage with urea. The treatments were constituted of T1: witness; T2: seed treatment (B: 0,1%; Cu: 0,1%; Mo: 2,%; Zn: 4,6%); T3: seed treatment + foliar fertilization at 25 DAE (B: 0,3%; Mn: 2,%; Mo: 1%; Zn: 3% + amino acids); T4: seed treatment + foliar application of amino acids at 25 DAE; T5: seed treatment + foliar application of amino acids in the pre and post-bloom (40 and 50 DAE); T6: foliar fertilization at 25 DAE (B: 0,3%; Mn: 2%; Mo: 1,%; Zn: 3% + amino acids); T7: foliar application of amino acids at 25 DAE; T8: foliar application (B: 0,3%; Mn: 2%; Mo: 1,%; Zn: 3% + amino acids) in the pre and post-bloom (40 and 50 DAE). It was evaluated: final yield, number of pods/plants, number of grains/pods and the mass of 100 grains. The results did not show relevant difference. Key-words:Phaseolus vulgaris, foliar fertilization...

Introduction: The nutritional status of micronutrients in lactating adolescent women is crucial to guarantee an adequate secretion of these in breast milk and, consequently, an adequate nutritional status of children. Hence, more attention should be given to micronutrient status of adolescent mother who breastfeed. This study aimed to evaluate the influence of multimicronutrients supplementation upon nutritional status of iron, copper, zinc and calcium of lactating adolescent mother from low socioeconomic status in Rio de Janeiro/Brazil. Methods: We conducted a randomized, placebo-controlled trial. During 60 days, 36 adolescents were allocated into two groups: supplemented group (SG) with 17 volunteers, receiving daily multimicronutrients supplement and the placebo group (PG) with 19 volunteers, receiving an inert compound. Plasma iron, copper, zinc and calcium and hemoglobin were determined at 7, 11 and 15 of the postpartum weeks (PPW). The effect of supplementation was analyzed by analysis of variance, comparing the differences between groups and within groups. Results: The average age of volunteers was 17.1 ± 0.8 for the supplemented group and 16.3 ± 1.4 for the placebo group. We observed an increase in the mean concentration of zinc (p < 0.05) and hemoglobin (p < 0.05) in the SG during the study (60 days)...