Evaluation of the metabolizable energy value for growing lambs of the Mucuna pruriens seed and the whole pod

Whole pod and seeds of velvet bean (Mucuna pruriens) were included in diets for growing sheep used to validate previously estimated ME values of 9.7 MJ and 12.6 MJ for whole pod and seed respectively. Twenty-four lambs, 15 females and nine males of 18.7 ± 2.4 kg average weight, were allocated in three treatments using a completely randomized block design with eight replicates per treatment. Each group was given a diet with a ratio of 60% of Napier grass (Pennisetum purpureum) and 40% of a supplement with the addition of 0%, 50% whole pod or 66% of M. pruriens seeds, for TI, TII and TIII respectively. Diets were formulated to meet the requirements for 100-g daily live weight gain (LWG). The total dry matter intake (836 g a⁻¹ d⁻¹, forage + supplement), LWG (90 g a⁻¹ d⁻¹) and feed conversion (9.66 kg DM/kg LWG) of lambs from TIII were lower (P < 0.05) compared to 941 g, 121 g, and 7.78 kg DM/kg LWG from TII and 976 g, 132 g and 7.50 kg DM/kg LWG from TI respectively. No difference was found (P > 0.05) between TI and TII in the three evaluated variables. The ME values of whole pod and seeds of M. pruriens used in this work were validated. It was concluded that M. pruriens can be included as a component in diets for growing sheep, as a partial replacement of conventional feedstuffs.     

Nondestructive evaluation of heat-treated Eucalyptus grandis Hill ex Maiden wood using stress wave method

The objectives of this study were to evaluate the effect of heat treatment of eucalypt wood (Eucalyptus grandis Hill ex Maiden) on the dynamic modulus of elasticity by using the stress wave nondestructive method and also to determine the air-dry density variation, weight loss and equilibrium moisture content following treatment. Heat treatments were performed at four different temperatures (180, 200, 215 and 230°C) and for three different durations (15?min, 2 and 4?h). The results revealed a significant reduction in air-dry density following heat treatment independent of temperature and time. A significant weight loss was observed between and within treatments. The treatment at 230°C for 2 and 4?h produced a weight loss of 20.5 and 26.5%, respectively, which was statistically different from other treatment conditions. The dynamic modulus of elasticity decreased by about 13% in the most severe treatment (230°C for 4?h). Depending on the temperature and time, the equilibrium moisture content was significantly reduced within the range of 40–74%.     

Correlation between clinical signs of depth of anaesthesia and cerebral state index responses in dogs with different target-controlled infusions of propofol

ObjectiveTo evaluate if the cerebral state index (CSI), measured by a Cerebral State Monitor (CSM), can predict depth of anaesthesia as assessed clinically or by estimated propofol plasma concentrations.Study designProspective clinical study.AnimalsFourteen mixed breed dogs, weighing 24.5 ± 4.7 kg, scheduled to undergo neutering procedures.MethodsDogs were premedicated with 0.05 mg kg^?1 acepromazine intramuscularly. The CSM and cardiovascular monitoring equipment were attached. Anaesthesia was induced with propofol using a target controlled infusion (TCI) to varying plasma propofol targets (PropCp). Following endotracheal intubation the dogs were ventilated with oxygen. Anaesthetic maintenance was with propofol by TCI. A PropCp of 3 μg dL^?1 was set initially, then PropCps were increased in 1 μg dL^?1 steps to 7, 9 and then 11 μg dL^?1. Each PropCp was held constant for a 5 minute period, at the end of which depth of anaesthesia was classified using a previously evaluated scale of ‘planes’ based on palpebral and corneal reflexes and eye position. Cerebral state index (CSI), burst suppression (BSR) and electromyogram were measured at these time points. The prediction probability (PK) of these variables, or of the PropCp in predicting depth of anaesthesia was calculated.ResultsThe PKs for predicting anaesthetic planes were 0.74, 0.91, 0.76 and 0.78 for CSI, BSR, EMG and PropCp, respectively. The PKs for PropCp to predict CSI, BSR and EMG were 0.65, 0.71 and 0.65 respectively.Conclusion and clinical relevance The Cerebral State Monitor was able to detect very deep planes of anaesthesia when BSR occurs, but was not able to distinguish between the intermediate anaesthetic planes likely to be used in clinical anaesthesia.     

Land use vs. fragment size and isolation as determinants of small mammal composition and richness in Atlantic Forest remnants

The remaining Atlantic Forest fragments are structurally isolated by a matrix of pastures, plantations, or urban areas, and most remnants are small (<100 ha). Island biogeography theory has been used to predict the effects of such fragmentation in the remaining fragments, but human activities and land use around fragments may be equally important. A related question is which aspects of land use have a strong effect on biodiversity. We compare the relative importance of fragment size and isolation vs. land use around fragments as determinants of composition and richness of small mammals in Atlantic Forest fragments. We also compare two aspects of land use around fragments, economic activity (peri-urban, agriculture, cattle), and property ownership (peri-urban, low income rural producers, affluent rural producers). Small mammals were surveyed in 21 fragments varying from 12 to 250 ha, and in two sites of continuous forest in the Macacu River watershed, State of Rio de Janeiro, Brazil, from 1999 to 2007. The effects of land use, fragment size and isolation were formulated as eleven candidate models, compared by Akaike Information Criteria. In the models selected, species composition was associated more strongly with fragment size, followed by isolation, with a smaller effect of property ownership. Species richness was determined mostly by fragment isolation, but also by a negative effect of agriculture when it was the dominant economic activity. Regardless of the critics to island biogeography theory, fragment isolation and size were by far the most important determinants of species composition. Economic activity and property ownership allowed the detection of subtle but important effects of land use on species composition and richness.     

Soil CO2 efflux and extractable organic carbon fractions under simulated precipitation events in a Mediterranean Dehesa

The magnitude of CO₂ efflux pulses after rewetting a dry soil is highly variable and the factors regulating these pulses are poorly understood. In this field experiment, we aimed to study the C dynamics after simulated summer rainstorms in a Mediterranean open holm oak woodland (dehesa). We hypothesized that because the herbaceous cover is mostly dead during the summer in this ecosystem, the short-term CO₂ efflux (SR) after rewetting could mainly be explained by different measurable soil C fractions: i) K₂SO₄-extracted soil C (EOC); ii) microbial biomass C (MBC); or iii) chloroform-fumigated extracted C (CFE). On both grazed and abandoned dehesa sites, we simulated three summer rain events at two-week intervals and we measured SR discontinuously in three plots under tree canopy and in another three plots in open grassland. In each plot, C fractions and water content were estimated before (2 h) and after (36 h) each irrigation event. Following rewettings, SR increased up to ten times compared with non-irrigated plots. The CFE actually increased after rewetting in the first two irrigations but not in the third event, suggesting that the capacity of the soil to release labile organic C from soil aggregates or litter was reduced after each irrigation event. Overall, the C released as CO₂ in the first 24 h was related to the CFE existing before rewetting, which may help to explain the spatial variability in SR. However, the explained variability decreased after each irrigation, suggesting a change to a less labile composition of the CFE fraction as a consequence of multiple drying-rewetting cycles.     

Calcareous amendments in truffle culture: A soil nutrition hypothesis

Several statistical studies have indicated that a high concentration of active carbonate in the soil favours Tuber melanosporum fruit body production. The amount of active carbonate is significantly higher and the total carbonate is significantly lower inside than outside the T. melanosporum brûlés. These statistical patterns and other works show that T. melanosporum mycelia may acidify their immediate soil environment and solubilise carbonated fractions. Subsequently, the particular environmental conditions of brûlé soils may favour a secondary carbonate precipitation with a net increase in active carbonate which would in turn favour T. melanosporum mycelia. The greater brûlé size and fruiting are simultaneously both related to how well the fungus is growing, suggesting that the model which best explains the cause-effect of all these observations is a feedback process. Other statistical studies suggest that active carbonate favours increased fruiting of T. melanosporum as compared with Tuber aestivum, Tuber mesentericum and Tuber rufum, which has led to the use of calcareous amendments in truffle culture. We have studied the carbonated fractions of 46 soil samples from T. melanosporum plantations contaminated and uncontaminated with Tuber brumale (a serious problem in truffle culture), and it appears that the use of calcareous amendments does not serve to eradicate T. brumale from these plantations. However, we have observed the positive effect of calcareous amendments on the production of fruit bodies of both species. The similar response by T. melanosporum and T. brumale to soil active carbonate may be related to the close phylogenetic relationships between both species. Based on these findings, we propose a new soil nutrition hypothesis as a guide for research procedures in truffle soil ecology. Soils which are high in active carbonate lead to host plant chlorosis, which is a symptom of an underlying nutrient deficiency. This nutrient deficiency could lead to greater colonisation of T. melanosporum ectomycorrhizas and favour the growth of mycelia, fruit body production and brûlé development, which in turn encourages the formation of new amounts of active carbonate on the basis of the proposed feedback model.     

Partitioning carbon fluxes in a Mediterranean oak forest to disentangle changes in ecosystem sink strength during drought

Net carbon flux partitioning was used to disentangle abiotic and biotic drivers of all important component fluxes influencing the overall sink strength of a Mediterranean ecosystem during a rapid spring to summer transition. Between May and June 2006 we analyzed how seasonal drought affected ecosystem assimilation and respiration fluxes in an evergreen oak woodland and attributed variations in the component fluxes (trees, understory, soil microorganisms and roots) to observations at the ecosystem scale. We observed a two thirds decrease in both ecosystem carbon assimilation and respiration (R_eco) within only 15 days time. The impact of decreasing R_eco on the ecosystem carbon balance was smaller than the impact of decreasing primary productivity. Flux partitioning of GPP and R_eco into their component fluxes from trees, understory, soil microorganisms and roots showed that declining ecosystem sink strength was due to a large drought and temperature-induced decrease in understory carbon uptake (from 56% to 21%). Hence, the shallow-rooted annuals mainly composing the understory have a surprisingly large impact on the source/sink behavior of this open evergreen oak woodland during spring to summer transition and the timing of the onset of drought might have a large effect on the annual carbon budget. In response to seasonal drought R_eco was increasingly dominated by respiration of heterotrophic soil microorganisms, while the root flux was found to be of minor importance. Soil respiration flux decreased with drought but its contribution to total daily CO₂-exchange increased by 11.5%. This partitioning approach disentangled changes in respiratory and photosynthetic ecosystem fluxes that were not apparent from the eddy-covariance or the soil respiration data alone. By the novel combination of understory vs. overstory carbon flux partitioning with soil respiration data from trenched and control plots, we gained a detailed understanding of factors controlling net carbon exchange of Mediterranean ecosystems.     

Relationship of parental genetic distance with agronomic performance,specific combining ability,and predicted breeding values of raspberry families

Previous findings in some crops suggest that parental distance is correlated with heterosis and agronomic performance. However, this pattern is not always evident in the progeny. The present study aimed to assess the relationship of parental distance with the agronomic performance of raspberry families and three estimators based on non-environmental effects: specific combining ability, general combining ability, and best linear unbiased prediction. A total of 35 genotypes, including eight open-pollinated raspberry cultivars and their 28 F₁ hybrids, were scored for vegetative and fruit traits. The relationship between estimators and parental distance ranged from 0.02 to 0.66. The estimators based on purely additive effects were superior to the per se performance of raspberry crosses. Additionally, it was observed that the specific combining ability—as an estimator associated with the parental genetic relatedness—performed poorly, and low correlation coefficients were observed for most of the traits. It was found that the degree of association for the estimators increased when narrow-sense heritability was high. It is concluded that the estimators based on only additive effects show a better association with parental relatedness, and therefore parental distance was an effective parameter in identifying crosses with high yield and large fruit size.     

Physiological and biochemical responses of <Emphasis Type="Italic">Dolichos lablab</Emphasis> L. to cadmium support its potential as a cadmium phytoremediator

Purpose

This study aims to investigate the response of a high biomass producer non-hyperaccumulator legume plant species, Dolichos lablab L., to cadmium (Cd) stress for phytoremediation process.

Materials and methods

Three individual experiments were carried out to assess physiological and biochemical parameters to support the use of this plant species as a phytoremediator. The first experiment was carried out in Cd-contaminated soil while the second and third experiments were conducted in sand in which Cd was applied to study biochemical responses. Analysis of mineral nutrition, phytoremediation parameters, antioxidant response, and protein identification by gel-based proteomics were performed.

Results and discussion

Good tolerance to Cd under moderate level of contamination was observed. Mineral nutrition was little affected, and phytoremediation index was satisfactory. Additionally, biochemical responses based on antioxidant enzyme analysis were well responsive in roots, reflecting the capacity of Cd stress attenuation in this organ. A proteomic analysis revealed positive regulation of root proteins involved in carbohydrate, amino acids, nitrogen metabolism, and abiotic/biotic stress response, which together may contribute to create a scenario to overcome Cd-induced stress.

Conclusions

Based on the physiological and biochemical results, we concluded that D. lablab L. is suitable for phytoremediation/phytostabilization purposes.

     

Characterization of kaolinite in the hardsetting clay fraction using atomic force microscopy,X-ray diffraction,and the Rietveld method

Purpose

Brazilian soils that present extremely hard sub-superficial horizons when dry and friable when humid are similar to the Australian and South African hardsetting horizons whose hardness can be mainly related to low crystallinity. Studies involving refinement by the Rietveld method with X-ray diffraction (RM-XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and their relation have not been carried out in hardsetting horizon soils. Thus, the objective of this study is to obtain information about the kaolinite in the hardsetting horizon of a Yellow Argisol clay fraction, taking into consideration the results of isomorphic substitution, crystallite average size, and microstrains, relating them to particle image analysis regarding their morphology and size.

Materials and methods

Soil samples were collected in the hardsetting horizon of a Yellow Argisol in the Coastal Tablelands region, which covers the whole Brazilian Northeast coast and part of the Southeast region. The sample was powdered, sieved, and submitted to dispersion and physical fractioning process by sedimentation. The clay fraction was analyzed by RM-XRD, AFM, and SEM techniques.

Results and discussion

The RM-XRD provided improvement of indices with isomorphic substitutions in the goethite [Fe_0.70Al_0.30O(OH)], kaolinite [Al_1.44Fe_0.56Si₂O₅(OH)₄], and halloysite [Al_1.42Fe_0.58Si₂O₅(OH)₄]; 29 nm crystallite average size; 5 × 10^?3 microstrain; and 49.5% kaolinite. AFM analyses indicated particle average size from 80 to 250 nm and average height from 60 to 80 nm. By relating this data, it was possible to estimate that the particles under analysis are kaolinite composed of 3 to 9 crystallites and stacking of 88 to 112 layers.

Conclusions

The process, analyses, and comparisons such as crystallographic and morphologic information about the kaolinite mineral particles contribute to the comprehension of the hardsetting horizon soil nature as well as other soils that present minerals with a high degree of isomorphic substitution.