Condensed Tannins and Total Phenols in \u3ci\u3eStylosanthes\u3c/i\u3e spp.

Rangelands, such as the species of the genus Stylosanthes, are plants highly selected by animals and represent an important forage source for livestock in the Northeast region of Brazil. Plants of this genus are naturally occurring in several places in Brazil and other semi-arid areas. The variability of condensed tannins and total phenols in different Stylosanthes accessions is still poorly characterized. Based on that, the objective of this study was to quantify the content of condensed tannins and total phenols of Stylosanthes accessions collected in different physiographic zones of the State of Pernambuco and cultivated in germplasm banks. The work was carried out in two germplasm banks in the municipalities of Serra Talhada and Carpina in Pernambuco-Brazil. These regions have different edaphoclimatic characteristics. The analyzes were performed on samples of the whole plant (leaves and stems) collected at 20 cm height. The design was completely randomized, with accessions representing the fixed effects treatments. The data were submitted for analysis of variance, and the means were compared by the Scott-Knott test at a level of 5%. The Stylosanthes accessions cultivated in the active germplasm banks of the municipalities of Carpina and Serra Talhada showed statistically significant differences (P \u3c 0.05) among accessions in their concentrations of condensed tannins and total phenols. For the accessions cultivated in the active germplasm bank of Serra Talhada, six groups were formed. The concentrations of condensed tannins ranged from 5.6 to 63.3 mg g-1, and the total phenols ranged from 13.7 to 100.0 mg g-1in the cultivars from Serra Talhada. Likewise, condensed tannins ranged between 16.6 and 142.1 mg g-1, and total phenols ranged from 38.4 and 294.1 mg g-1 for the three groups from the municipality of Carpina. There is variability in the contents of condensed tannins and total phenols among accessions of Stylosanthes spp

Argon Abundances in the Solar Neighborhood: Non-LTE Analysis of Orion Association B-type Stars

Argon abundances have been derived for a sample of B main-sequence stars in the Orion association. The abundance calculations are based on NLTE metal line-blanketed model atmospheres calculated with the NLTE code TLUSTY and an updated and complete argon model atom. We derive an average argon abundance for this young population of A(Ar) = 6.66 +- 0.06. While our result is in excellent agreement with a recent analysis of the Orion nebula, it is significantly higher than the currently recommended solar value which is based on abundance measurements in the solar corona. Moreover, the derived argon abundances in the Orion B stars agree very well with a measurement from a solar impulsive flare during which unmodified solar photospheric material was brought to flare conditions. We therefore argue that the argon abundances obtained independently for both the Orion B stars and the Orion nebula are representative of the disk abundance value in the solar neighborhood. The lower coronal abundance may reflect a depletion related to the FIP effect. We propose a new reference value for the abundance of argon in the solar neighborhood, A(Ar) = 6.63 +- 0.10, corresponding to Ar/O = 0.009.Comment: to appear in Astrophysical Journal, 24 pages, 3 figures; minor corrections after referee's repor

Vegetative Propagation of \u3cem\u3eStylosanthes scabra\u3c/em\u3e

One way to multiply genetically desirable plants in a more uniform manner is to use vegetative propagation, such as using plant cuttings. This technique multiplies a single plant into several, in an easy low-cost system (Fachinello et al. 2005), so it is useful in plant breeding. This technique may be enhanced through the use of hormonal regulators, with indolebutyric acid (IBA) being most frequently used, because of its stability in hydroalcoholic solution, low sensitivity to biological degradation and good establishment of adventitious roots (Fachinello et al. 1995). In spite of its large-scale use for fruit production, the technique is not commonly used for forage species, such as Stylosanthes. We evaluated different concentrations of IBA for root establishment and initial development of Stylosanthes scabra cuttings

Role of nutrients on lipid peroxidation and antioxidant defense system

Espécies reativas de oxigênio são formadas durante o metabolismo aeróbico e podem danificar lipídios, proteínas, carboidratos e o DNA. Essas reações, potencialmente deletérias, são controladas por um sistema de antioxidantes enzimáticos e não enzimáticos, que eliminam os próoxidantes e “varrem” os radicais livres. Esta revisão mostra o papel de alguns nutrientes na peroxidação lipídica e no sistema de defesa antioxidante. Enfatizam-se os mecanismos que levam ao dano oxidativo e sua proteção, assim como as implicações na saúde humana.Reactive oxygen species are generated in aerobic metabolism and can damage lipids, proteins, carbohydrates and DNA. These potentially deleterious reactions are controlled by a system of enzymatic and non-enzymatic antioxidants which eliminates prooxidants and scavenge free radicals. This revision focuses the role of particular nutrients in lipid peroxidation and antioxidant defense system. Emphasis was placed on mechanisms for damage and protection, as well implications in human healthy issues

Animal Performance in Signalgrass Monoculture or in Silvopastoral Systems

Silvopastoral systems (SPS) can increase overall productivity and long-term income due to the simultaneous production of trees, forage, and livestock. This 2-yr study evaluated animal performance and herbage responses in C4-grass monoculture or in SPS in the sub-humid tropical region of Brazil. The experimental design was randomized complete block with three replications. Treatments were: Urochloa decumbens (Stapf.) R. Webster (Signalgrass) + Mimosa caesalpiniifolia Benth (SPS-Mimosa); Signalgrass + Gliricidia sepium (Jacq.) Kunth ex Walp (SPS-Gliricidia); and Signalgrass monoculture (SM). Response variables included herbage and livestock responses. Cattle were managed under continuous stocking with variable stocking rate. There was interaction between treatment × month for herbage mass. Green herbage accumulation rate ranged from 20 to 80 kg DM ha-1d-1 across months, with SPS-Mimosa presenting lower rates. Average daily gain was greater in SPS-Gliricidia, followed by SM, and SPS-Mimosa, respectively (0.77; 0.56; 0.23 kg d-1), varying across months. Stocking rate ranged from 0.86 to 1.6 AU ha-1. Total gain per area during the experimental period was greater for SPS-Gliricidia (423 kg BW ha-1), followed by signalgrass in monoculture (347 kg BW ha-1), and SPS-Mimosa (50 kg BW ha-1). Silvopasture systems using signalgrass and gliricidia enhanced livestock gains compared with signalgrass in monoculture, and mimosa trees outcompeted signalgrass, reducing livestock gains. Silvopasture systems with tree legumes have potential to provide numerous ecosystem services and reduce C footprint of livestock systems in the tropics, however, the choice of tree species is key and determined by which ecosystem service is prioritized

Management Effect on Rainfall Use Efficiency and Growth Rate of Spineless Cactus \u3cem\u3ecv.\u3c/em\u3e Miúda in Northeast Brazil

Spineless cactus has a high rainfall use efficiency. Under water deficit, they open their stomata during the night to capture atmospheric carbon dioxide when the air temperature is lower and relative humidity higher (Taiz and Zeiger, 2009), losing less water to the atmosphere. The rainfall use efficiency (RUE) can be expressed as the amount of water used by the crop to produce dry matter (Han and Felker, 1997). The RUE showed by spineless cactus, a CAM plant, is three to five times greater than the one observed in C3 and C4 plants (Felker and Russel, 1988; Nobel, 1991). Therefore, spineless cacti (Nopaleae opuntia) are important forage resource in northeast Brazil. Management practices, however, can affect the RUE and growth of spineless cactus, especially organic and mineral fertilization. Thus, the objective of this research was to evaluate the effect of organic and nitrogen fertilization and harvest frequency on rainfall use efficiency and growth rate of spineless cactus cv. Miúda (Nopalea cochenillifera Salm Dyck)

The angular size - redshift relation in power-law cosmologies

A linear evolution of the cosmological scale factor is a feature in several models designed to solve the cosmological constant problem via a coupling between scalar or tensor classical fields to the space-time curvature as well as in some alternative gravity theories. In this paper, by assuming a general time dependence of the scale factor, $R \sim t^{\alpha}$, we investigate observational constraints on the dimensionless parameter $\alpha$ from measurements of the angular size for a large sample of milliarcsecond compact radio sources. In particular, we find that a strictly linear evolution, i.e., $\alpha \simeq 1$ is favoured by these data, which is also in agreement with limits obtained from other independent cosmological tests. The dependence of the critical redshift $z_m$ (at which a given angular size takes its minimal value) with the index $\alpha$ is briefly discussed.Comment: 5 pages, 4 figures, LaTe