960 resultados para substrate


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The slow and uneven germination of Syagrus oleracea seeds represents a problem for its propagation, especially for commercial production. This work aimed to study the effects of substrate and mechanical scarification on the germination of S. oleracea seeds. Germination (% G), emergence rate (ER), leaf area (cm(2)), root length (cm), leaf dry mass (g) and root dry mass (g) were also determined. Non-scarified seeds sown in vermiculite germinated faster and showed higher germination (65%), as well as greater root length (16.55 cm). leaf dry mass (5.07 g) and root dry mass (12.41 g), when compared to the scarified seeds.

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Dypsis leptocheilos is highly valued as an ornamental palm. Its propagation is done by seeds; however, there is little information about this process. The objective of this work was to study the substrate and temperature effects on the germination of D. leptocheilos seeds. The experiments were carried out at FCAV/UNESP, Campus of Jaboticabal, São Paulo State, Brazil. In order to study the substrate effects, four treatments were arranged (coconut fiber, sand, vermiculite and Plantmax (R)) at 30 degrees C. For the temperature effects, six treatments were performed (temperature at laboratory conditions (21.5 degrees C and 72% RU), 25 degrees C, 30 degrees C, 35 degrees C, 20-30 degrees C and 25-35 degrees C), having the coconut fiber as the substrate. The experimental design was completely randomized, with four replicates of 25 disseminules per plot (seeds with attached endocarp). Water replacement was managed to maintain 100% of the retention capacity of the substrates. The germination tests were observed every two days, and conducted over 148 days for the substrate effects, and over 152 days for the temperature effects, when no more seed germination was noted. In order to determine the germination percentage (% G) and the Germination Speed Index (GSI), the seed was considered germinated when the germinative button appeared. At the end of the experiments, leaf area (cm(2)), root and shoot length (cm), root and shoot dry mass (g) were also obtained. Statistical analysis was performed and means were compared by the Tukey test. Germination rate and speed in coconut fiber was higher at 25 and 30 degrees C. However, when other substrates were tested at 30 degrees C, the highest germination percentage was observed in vermiculite, which also sustained better results for the seed germination and for the characteristics related to shoots and roots.

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A lichia é considerada em todo o mundo como a rainha das frutas, por sua aparência e sabor delicado. Atualmente, a cultura vem despertando interesse, principalmente no Estado de São Paulo, onde, em virtude dos problemas enfrentados pelos agricultores, destacando-se os de laranja e cana-de-açúcar, a procura por alternativas agrícolas vem se intensificando ainda mais. A propagação através de sementes não é recomendada comercialmente, pois as plantas de pé-franco são geneticamente muito desuniformes e apresentam período juvenil muito longo, demorando até 10 anos para entrar em produção; no entanto, a semente pode ser utilizada para a obtenção de porta-enxertos. Observou-se que a germinação de sementes de lichia ocorre rapidamente, reforçando a importância do uso de um substrato adequado. Pela análise dos resultados obtidos, verifica-se que o substrato que aparentemente permitiu as melhores combinações de água e disponibilidade de oxigênio para as sementes - casca de arroz carbonizada e areia lavada, foi o que proporcionou valores de germinação mais rápidos e mais altos.

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Com a procura cada vez maior de alternativas por parte dos produtores rurais e de frutas exóticas pelos consumidores, o mercado de frutíferas tem crescido consideravelmente. Neste contexto, a pitaya vem sendo procurada não apenas pelo exotismo de sua aparência, como também por suas características organoléticas. O presente trabalho foi realizado objetivando avaliar a influência do volume de substrato no desenvolvimento de mudas de pitaya vermelha, utilizando-se bandejas de poliestireno expandido com diferentes volumes de células: 10, 15, 30 e 65 mL. As avaliações, realizadas aos 90 dias, foram quanto: porcentagem de sobrevivência; ao número e altura dos cladódios (cm), ao comprimento da maior raiz (cm); às massas fresca e seca dos cladódios e das raízes (gramas). O delineamento experimental foi inteiramente casualizado. Os dados de porcentagem de sobrevivência foram transformados em arc sen para fins de análise estatística e as médias comparadas pelo teste de Tukey, a 5% de probabilidade. A sobrevivência e o desenvolvimento vegetativo das mudas de pitaya vermelha através de sementes foram diretamente proporcionais ao volume de substrato usado no experimento. Para formação de mudas de pitaya vermelha através de sementes é recomendado o uso de containeres com capacidade de 65 mL.

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

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P>The present work evaluates of harvested mushroom and viability of Agaricus bisporus growth in several casing materials based on spent mushroom substrate. The experiment consisted of eight casing layer, which six were made with spent mushroom substrate. The results confirm the usefulness of reincorporating the spent substrate in new cultivation cycles as an ingredient of casing mixtures. In general, biological efficiency was high, three of the SMS based-casings surpassing the threshold value of 100 kg 100 kg-1 of compost. The high electrical conductivity of mixtures containing a large proportion of spent substrate limits the extent to which it can be used, although mixing it with other materials (such as peat) reduces these values to acceptable levels. In short, it makes economic and environmental sense to reuse spent mushroom substrate as an ingredient of alternative casing materials.

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Botryosphaeria rhodina and Trichoderma harzianum Rifai were grown on botryosphaeran (an exopolysaccharide (EPS) of the beta-1,3; 1,6-D-Glucan type produced by B. rhodina) as sole carbon source with the objective of producing beta-glucanases of the beta-type. Conditions for beta-1,3-glucanase production by T harzianum were examined by a statistical response surface method, and showed maximal enzyme production at 5 days growth in media containing 1.5 g/1 of EPS. Good agreement was obtained between the experimental values of beta-1, 3-glucanase activity and the corresponding values predicted by the mathernatical model. The crude beta-1,3-glucanase preparations were active towards a number of different beta-1,3-glucans and beta-glucosides. The mycelium of B. rhodina also proved to be a good substrate for beta-1,3-glucanase production by both fungal species. (c) 2005 Published by Elsevier Ltd.

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It is well known that glucocorticoids induce peripheral insulin resistance in rodents and humans. Here, we investigated the structural and ultrastructural modifications, as well as the proteins involved in beta-cell function and proliferation, in islets from insulin-resistant rats. Adult male Wistar rats were made insulin resistant by daily administration of dexamethasone (DEX; 1mg/kg, i.p.) for five consecutive days, whilst control (CTL) rats received saline alone. Structure analyses showed a marked hypertrophy of DEX islets with an increase of 1.7-fold in islet mass and of 1.6-fold in islet density compared with CTL islets (P < 0.05). Ultrastructural evaluation of islets revealed an increased amount of secreting organelles, such as endoplasmic reticulum and Golgi apparatus in DEX islets. Mitotic figures were observed in DEX islets at structural and ultrastructural levels. Beta-cell proliferation, evaluated at the immunohistochemical level using anti-PCNA (proliferating cell nuclear antigen), showed an increase in pancreatic beta-cell proliferation of 6.4-fold in DEX islets compared with CTL islets (P < 0.0001). Increases in insulin receptor substrate-2 (IRS-2), phosphorylated-serine-threonine kinase AKT (p-AKT), cyclin D(2) and a decrease in retinoblastoma protein (pRb) levels were observed in DEX islets compared with CTL islets (P < 0.05). Therefore, during the development of insulin resistance, the endocrine pancreas adapts itself increasing beta-cell mass and proliferation, resulting in an amelioration of the functions. The potential mechanisms that underlie these events involve the activation of the IRS-2/AKT pathway and activation of the cell cycle, mediated by cyclin D(2). These adaptations permit the maintenance of glycaemia at near-physiological ranges.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The results of nanohardness measurements at a film surface and film-substrate interface are presented and discussed. An electron beam device was used to deposit a Ti film on a 304 stainless steel (304 SS) substrate. The diluted interface was obtained by thermal activated atomic diffusion. The. Ti film and Ti film-304 SS interface were analyzed by energy dispersive spectrometry and were observed using atomic force microscopy. The nanohardness of the Ti film-304 SS system was measured by a nanoindentation technique. The results showed the Ti film-304 SS interface had a higher hardness value than the Ti film and 304 SS substrate. The Ti film surface had a lower hardness due to the presence of a TiO2 thin layer.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Portuguese chestnut (Castanea sativa) is used for forest products, raw nuts and processed flour, paste, and candy. We studied the influence on germination efficiency of seed with and without partial tegument removal combined with different substrate composition (coconut fiber, pine compost and vermiculite) at São Paulo State University, Campus of Botucatu, São Paulo, Brazil. Randomized blocks were used in a factorial scheme 3x2 (three substrates x two seed types) consisting of six treatments with five replications (twelve seeds). Seeds were sowed in expanded polystyrene trays, with 72 cells, and maintained at 25 C under controlled environment. Rate, time elapsed and speed of seed germination was submitted to ANOVA and the average compared using Tukey's 5% test of probability and curves adjusted based on Gompertz regression. Coconut fiber or vermiculite associated with seed without partial tegument removal showed the highest germination rate, and coconut fiber with or without partial tegument removal displayed the fastest speed of seed germination.

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Anuran amphibians exhibit different patterns of energy substrate utilization that correlate with the intensity of vocal and locomotor activities. Given the remarkable differences among species in breeding and feeding strategies, and the different ways energy is used in the whole animal, the suggested correlations between calling and locomotor behavior and the level of energy substrates in the muscles responsible for such activities are more complex than previously reported. We explored the relationships between calling and locomotor behavior and energy supply to trunk and hindlimb muscles, respectively, within the ecologically diverse tree-frog genus Scinax. Specifically, we measured the relative amount of carbohydrates and lipids in these two groups of muscles, and in the liver of three species of Scinax that differ in vocal and locomotor performance, and compared our results with those of two other species for which comparable data are available. We also compared the contents of lipids and carbohydrates of conspecific males collected at the beginning and after 4 h of calling activity. The stomach content to potential feeding opportunities across species was also assessed in both groups of males. Scinax hiemalis and S. rizibilis exhibit comparatively low and episodic calling during long periods of activity whereas S. crospedospilus calls at higher rates over shorter periods. Male S. hiemalis had highest levels of trunk muscle glycogen followed by those of S. rizilbilis and S. crospedospilus, respectively. There was no correlation between total lipid content in trunk muscle and calling rate among different species, suggesting that other metabolic aspects may be responsible for the energetic support for vocal activity. The levels of lipids and carbohydrates in trunk and hindlimb muscles and liver of males collected at the beginning and 4 h into the calling period were similar across species, so the extent of energetic reserves does not appear to constrain vocal or locomotor activity. Finally, we found exceptionally high levels of carbohydrates and lipids in the liver of S. rizibilis, a trait perhaps related to a long and demanding breeding period.