Comparison of temporary or continuous immersion systems for micropropagation in liquid medium of axillary shoots of Salix viminalis.

In this study the response to culture in liquid medium of axillary shoots of two woody species, chestnut and willow, has been compared. Both species differ in their recalcitrance to micropropagation, especially in their rooting and acclimatization abilities. Parameters such as explant type, supporting material, bioreactor type, number of immersions and/or aerations were tested. Continuous and temporary immersion systems have been applied to both species and several differences were detected. Hyperhydricity was not observed in willow shoots cultured in liquid medium with aeration, but this disorder affected chestnut cultures unless supporting materials as rockwool cubes were used. Besides, willow shoots rooted spontaneously in liquid culture, whereas chestnut shoots required an auxin treatment. In spite of these differences, both species showed better performance in liquid culture than in semi-solid medium, and shoots from an adult willow genotype and from eight selected chestnut genotypes (hybrids of European and Asian chestnuts) were successfully rooted and acclimatized.Peer reviewe

Nonlinear Supersymmetry as a Hidden Symmetry

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Produção de sementes e óleo de andiroba em área de várzea do Amapá.

Editado por Lúcia Helena de Oliveira Wadt

Silagem de capim como estratégia de alimentação de bovinos no período da seca.

Estacionalidade da produção de forragem; silagem de capim.Resumo expandido

AN EXPERIMENTAL STUDY OF THE CONVECTIVE HEAT TRANSFER ENHANCEMENT: APPLICATION OF TURBULENCE PROMOTERS

This work presents an experimental study addressing the effects of turbulence promoters on heat transfer rate at circular cylinder in external cross flow. Within this framework, the work focuses on assessing the effects of three kind of turbulence promoters (with circular, square and hexagonal cross sections) on convective heat transfer enhancement. The distance from turbulence promoters to the circular cylinder (50, 100 and 150mm upstream), as well as the free stream velocity inside the wind tunnel (Reynolds number) were the parameters investigated. The validation of the experimental methodology was performed by comparing the present results with empiric correlations available in the literature. The main results indicate that the convective heat transfer coefficient was enhanced when using turbulence promoters. The highest heat transfer enhancement obtained was around 25% correponding to the case of square turbulence promoter placed closely (50mm) to the circular cylinder. Finally, it is worth mentioning that all the experimental results for the convective coefficient were condensed in a new empirical correlation with good accuracy

Produção de bebida obtida a partir da fração retida na microfiltração da polpa de açaí.

bitstream/item/91525/1/2009-CTE-0154.pd

Mass production of Bacillus subtilis and Trichoderma viride for the control of Phyllosticta citricarpa (Teleomorph: Guignardia citricarpa).

The work was aimed at studying the production of cells and metabolites of Bacilius subtilis (ACB-69) and of Trichoderma viride conidia (ACB-14) on different substrates, since they can potentially control Phyllosticta citricarpa. Our results showed that the medium consisting of cotton meal added of hydrolized protein provided the highest yield of B. subtiiis cells (2.44 x IO9 cells/mL), after the culture had been incubated for three days. This liquid substrate also provided conditions for the bacterium to produce thermostable metabolites, in sufficient amounts to inhibit the plant pathogen's micelial growth. The production of B. subtilis under the solid fermentation system performed better on the brewers rice substrate; the number of bactéria; cells decreased as the substrate concentration increased. In general, the liquid medium yielded a higher amount of B. subtilis than the solid medium. With regard to the large scale production of T. viride, it was verified that the substrates tested had a low spore production; the best substrate among those tested (com cob + hydrolized protein) only yielded 2.17 x IO6 conidia/mL. O objetivo foi estudar a produção de células e de metabólitos de Bacillus subtilis (ACB-69) e de conídios de Trichoderma viride (ACB-14) em diferentes substratos, pois apresentam potencial para o controle de Phyllosticta citricarpa. O meio constituído de farelo de algodão acrescido de proteína hidrolisada foi o que proporcionou maior produção de células de B. subtilis (2,4 x 109 células/mL), após três dias de incubação da cultura. Esse substrato líquido também propiciou condições para que a bactéria produzisse metabólitos termoestáveis e, em quantidades suficientes para inibir o crescimento micelial do fitopatógeno. A produção de B. subtilis pelo sistema de fermentação sólida foi melhor no substrato quirera de arroz sendo que o número de células da bactéria diminuiu à medida que aumentou a concentração do substrato. De um modo geral, o meio líquido foi superior ao sólido para a produção de B. subtilis. Com relação à produção de T. viride, verificou-se que os substratos testados apresentaram baixa produção de esporos, sendo que o melhor substrato testado (sabugo de milho + proteína hidrolisada) produziu apenas 2,2 x 106 conídios/mL