Relação fósforo e magnésio na fertilidade do solo, no estado nutricional e na produção da alfafa

Com o objetivo de avaliar a influência da relação P:Mg na fertilidade do solo, no estado nutricional e na produção de matéria seca da alfafa, foi realizado um experimento em vasos com Latossolo Vermelho Amarelo distrófico, segundo delineamento inteiramente casualizado, em esquema de parcelas subdivididas, com três repetições. Os tratamentos foram constituídos de combinações de P (doses: 0, 100, 200 e 400 mg kg-1, fonte: superfosfato triplo) e Mg (doses: 0, 100 e 200 mg kg-1, fonte: cloreto de magnésio), nas proporções de 0, 0,5, 1, 2 e 4. No período experimental, foram realizados três cortes, com intervalo de 30 dias (subparcelas). Os resultados demonstraram que o incremento da relação P:Mg e das doses de P e de Mg aumenta a produção de matéria seca. O teor de P e as combinações de P:Mg no tecido vegetal apresentaram estreita relação com a proporção desses nutrientes no solo. A relação 2:1 acarretou maior teor de clorofila e N na matéria seca, enquanto altas quantidades de P no solo diminuíram a absorção de K.

Composição Corporal e Exigências Nutricionais de Magnésio, Potássio e Sódio de Cordeiros Santa Inês em Crescimento dos 15 kg aos 25 kg de Peso Vivo

This study was carried out to determine body composition and magnesium, potassium and sodium requirements for weight gain of Santa Ines lambs (hairy coat breed). Eighteen animals were used with average 15 kg initial LW. At the beginning of the experiment, six animals were slaughtered for the determination of the amount of each mineral retained in the body, and serving as reference animals in the comparative slaughter technique. The remaining 12 animals were divided in two groups: six were ad libitum fed and six animals were restricting fed at maintenance plus 20%. The animals from the ad libitum and restrict feeding groups started in the experimental period by pairs and they both were slaughtered when the animals from the ad libitum group reached 25 kg LW. The estimates of magnesium, potassium and sodium body composition were obtained through the prediction equations obtained by the logarithm regression of the amount of each present minerals in the empty body in function of the empty body weight (EBW). The net requirements for weight gain were obtained through the derivation of these prediction equations. The estimates of body composition per kg EBW for the animals from 15 to 25 kg were: 0.591 and 0,578 g for Mg: 2.914 and 2.776 g for K 1.830 and 1.637 g for Na; and the net requirements for kg weight gain were: 0.515 and 0.503 g for Mg: 2.408 and 2.294 g for K; 1.315 and 1.177 g for Na, respectively.

Produção de matéria seca de feijoeiros submetidos a diferentes níveis de magnésio em solução nutritiva

The effect of Mg levels in nutrient solution upon root, stem, leaf, fruit and total dry matter production of common bean (Phaseolus vulgaris L. cv. Carioca) was studied. Bean plants were grown in Hoagland & Arnon n. 2 solution modified to obtain 2.4, 24.3, 48.6, 72.9 and 97.2 ppm of Mg. The experimental design was a split-plot factorial replicated three times with five Mg levels and five samplings which were done fortnightly. Results were compared with those observed in plants submitted to a nutrient solution with 48.6 ppm of Mg concentration, considered the ideal Mg content. Only a mild prejudicial effect was observed with Mg excessive levels. Stem, leaves and total dry matter were higher when 2.4 ppm were used, suggesting this level as the concentration chosen for the culture of common bean.

Magnésio, cálcio e potássio em sementes e cotilédones de feijoeiros e sua transferência para plantas jovens

Magnesium, calcium and potassium concentration in the seeds and cotyledons of Phaseolus vulgaris L. cv. Carioca and its translocation from the cotyledons to the plant were evaluated. For such an evaluation plants were cultivated during the cotyledons phase and were irrigated with deionized water. Three samplings of cotyledons completely randomized were done and replicated ten times, before its senescence and fall, at 8, 12 and 15 days after the germination of the seeds. Fresh and dry matter of the cotyledons and its magnesium, calcium and potassium content were determinated in every sample. These parameters were also determined in the seeds from the same lot. Potassium concentration was higher than magnesium in both seeds and cotyledons. Calcium presented the lesser concentration both in seeds and cotyledons. These minerals were translocated from the seeds and cotyledons to the young plants. Eight days after germination 59% of the magnesium, 78% of the calcium and 71% of the potassium were translocated to the plants. Fifteen days after germination these percentages were respectivaley 73%, 82% and 91%. Thus, magnesium was the less and potassium was the most translocated mineral at the end of the study.

Desenvolvimento do manjericão (Ocimum basilicum L.) cultivado em solução nutritiva com diferentes níveis de magnésio

The aim of this experiment was to study the influence of several levels of magnesium on development and essential oil content of basil, plants were cultivated using Hoagland and Arnon (1950) number one 1 complete solution, containing 48.6 mg L -1 and with decreasing levels of magnesium (24.3 mg L -1 and 12.1 mg L -1). The experimental design was completely randomized, in a factorial scheme 3x3, which is, three levels of magnesium and three harvest times, with three replications each. The parameters evaluated were the stem length, leaf dry mass, stem dry mass, roots dry mass, absolute growth rate (AGR), relative growth rate (RGR), net assimilatory rate (NAR), leaf area ratio (LAR), leaf mass ratio (LMR), dry mass distribution on several organs, stem and leaf/root ratio and essential oil yield, all those measured in three harvest time 30, 60 and 90 days after transplantation (DAT). Plants cultivated with the lower levels of magnesium showed no symptoms of deficiency, but showed differences in the parameters studied. Essential oil yield was higher at 30 DAT for plants cultivated with 12.1 mg L -1 the magnesium. Our results suggests that Hoagland and Arnon (1950) no 1 complete solution overestimates the level of magnesium, as has been observed in several other plant species.

Investigação comparativa das propriedades estruturais do diboreto de magnésio dopado com compostos de carbono

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Propriedades de transporte eletrônico em filmes finos policristalinos de diboreto de magnésio (MGB IND.2') analisados pelo modelo de Bloch-Grüneisen

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Efeito da dieta com deficiência de magnésio sobre a manutenção da osseointegração de implantes de titânio: análise radiográfica, densitométrica e de torque reverso

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito da deficiência de magnésio na dieta sobre a densidade e o metabolismo ósseo ao redor de implantes com osseointegração estabelecida: estudos em ratos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento de semicubos de roda aeronáuticos: uma contribuição metalúrgica em liga ultra-leve magnésio AZ-91C à Força Aérea Brasileira

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento de eletrodos modificados para determinação de cálcio e magnésio em biodiesel

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação metabólica em litíase urinária: papel do magnésio e sódio urinários como fatores de risco na litogênese

Pós-graduação em Bases Gerais da Cirurgia - FMB