939 resultados para Subsolo cerrado


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Vinasse, a liquor effluent from the alcohol and sugar making industry, was applied annually for twelve years to medium-textured red-yellow latosols under cerrado vegetation sensu stricto, to study the environmental impacts on the biotic and abiotic factors. Four plots were established of which two acted as control and the other two received annual doses of vinasse. The studies were begun in 1980 when the first annual dose of 20 L m-2 year-1 was added to the soil without removing the top scrub layer. Theses doses were added to the soil until 1983, but in 1984 the doses were increased to 50 L m-2 year-1 and used until 1991. Soil samples were taken at a depth of 15 cm every three months from 1987 to 1991. Twenty seven environmental variables in the vinasse-treated and untreated plots were studied. These factors consisted of different enzymatic activities, a number of filamentous fungi, bacteria, actinomycetes and other micro-organisms, nutrients and some micro-climatic factors. The results obtained were statistically analyzed using the Tukey test, Pearson correlation and variance test methods with replicates and three factors. Matrices were determined using the correlation coefficient method and were compared with those of earlier published studies in the same area. The comparison of the results helped characterize changes in the environmental factors studied and in the correlation between them, after using annual cumulative doses of vinasse. Positive effects were observed only for the first six years of this application but vinasse had negative effects after the seventh year. It is concluded that medium-textured red-yellow latosols cannot be treated with vinasse for proloned periods.

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Bioactivity-guided fractionation of several bioactive extracts obtained from Cerrado and Atlantic Forest plant species led to the isolation of potent DNA-damaging piperidine 1-5 and guanidine alkaloids 6-9 from Cassia leptophylla and Pterogyne nitens respectively, two common Leguminosae from Atlantic Forest. By means of biotechnological approach on Maytenus aquifolium, a species from Cerrado, moderate DNA-damaging sesquiterpene pyridine alkaloid 10-11 was isolated. Bioassay-guided fractionation on Casearia sylvestris, a medicinal plant species found in Cerrado and Atlantic Forest, led to the isolation of clerodane diterpenes 12-13 which showed effect on DNA. In addition, we have reported several interesting potent antifungal iridoids: 1β-hydroxy-dihydrocornin (14), 1α-hydroxy-dihydrocornin (15), α-gardiol (16), β-gardiol (17), plumericin (18), isoplumericin (19), 11-O-trans-caffeoylteucrein (20); ester derivative: 2-methyl-4-hydroxy-butyl-caffeoate (21), amide N-[7-(3'.4'-methylenedioxyphenyl)-2Z, 4Z-heptadienoyl] pyrrolidine (22) and triterpene viburgenin (23).

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In order to evaluate growth characteristics, adaptability, biomass production, nutrient recycling, nutrient distribution and the ability to regenerate degraded land, a trial using four multipurpose tree species (Leucaena leucocephala, Leucaena diversifolia, Acacia melanoxylon and Mimosa scabrella) was undertaken over two years in a distrophic red yellow latosol (oxisol) following a randomized block experimental design with four replications. At the age of two years, A. melanoxylon and L. diversifolia were the tallest species (5.25 and 4.97 m, respectively) and A. melanoxylon and M. scabrella had the largest diameters at 20 cm from tree base. Mimosa scabrella and A. melanoxylon had the highest dry matter production and quantity of nutrients in the above ground biomass. In all species, the highest nutrient contents were found in the leaves, followed by branches and stems. From all species, the highest Nutrient Utilization Efficiency Indexes were obtained for sulphur, phosphorous, and magnesium; L. diversifolia was the most efficient for nitrogen, potassium, calcium, sulphur, and manganese, while A. melanoxylon was the most efficient for phosphorus, magnesium, boron, iron, and zinc. Litter production levels over a three month period were as follows: M. scabrella > A. melanoxylon > L. diversifolia > L. leucocephala. Litter nutrient content was higher in M. scabrella than in the other species.

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Fruits have been considered an important feeding resource used not only by frugivorous birds, but also by omnivore and some insectivore species. In the present paper we are reporting the behavior of birds consuming fruits of Davilla rugosa (Dilleniaceae). Handling behavior and visits frequency were analyzed in order to infer about the potential ornithochoric seed dispersal. Focal observations were carried out from October to December 1999 in a cerrado fragment located in São Paulo State, Southeastern Brazil (21°58′S, 47°52′W). In 60 h of field work we recorded 241 visits of 13 passerine bird species consuming the fruits. The mean number of visits per hour and the standard deviation were 4.01 ± 4.88. All of the species were considered potential seed dispersers, since no pulp mashers or seed predators were observed. No temporal difference in visit frequency was found when all of the species were analyzed together or when they were individually considered. Generalist species were responsible for 68.5% of the visits, followed by frugivorous (22.82%) and insectivorous (8.71%). The main potential seed dispersers were Elaenia spp. (Tyrannidae), Tangara cayana (Emberizidae), Empidonomus varius (Tyrannidae), Turdus leucomelas (Muscicapidae) and Vireo chivi (Vireonidae). The high visit frequency observed suggests that D. rugosa fruits may be an important feeding resource for birds in the cerrado ecosystem, in the manner that this plant can be considered in management plans which intent to maintain or rescue bird communities.

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Constrictotermes cyphergaster builds arboreal nests in Cerrado sensu stricto of Brazil; inquiline termites and termitophiles frequently inhabit their nests. Measurements of the nests and the support trees (nest width and diameter; tree trunk circumference and inclination), colony size of C. cyphergaster and of Inquilinitermes and number of termitophiles were studied at the Parque Estadual da Serra de Caldas Novas. These variables were subjected to a Principal Component Analysis, producing four principal components. The first principal component refers to a multidimensional axis of nest size, encompassing variables related to nest and colony size, such as abundance per caste of C. cyphergaster and I. microcerus, number of termitophile species and the measurements of the nest. The number of soldiers and workers of C. cyphergaster and soldiers of Inquilinitermes increased proportionally to the axis of nest size, while the number of Inquilinitermes workers increased more quickly then the increase in the nest size. Both Inquilinitermes occurred mainly in larger nests. Almost half of the nests (47,5%) were inhabited by I. microcerus and 10% by I. fur.

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We present the results of the first bat inventory at the 'Serra das Araras' Ecological Station, MT, in the northwestern portion of the Cerrado domain. We captured bats using the traditional ground-level mist netting and, occasionally, high nets placed 3 m above the ground, and hand nets for hoosting bats. We recorded 23 species distributed in six families (Emballonuridae, Noctilionidae, Mormoopidae, Phyllostomidae, Molossidae, and Vespertilionidae), including Artibeus gnomus and A. anderseni, which had never been recorded in the Cerrado domain. © 2004 Instituto de Ciências Biológicas - UFMG.

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The objective of this study was determine the spatial distribution of genotypes of Terminalia argentea Mart et Suce. (Capitão-do-campo) in a natural population, aiming to outline strategy to genetic conservation in situ and ex situ. The population (Terminalia argentea) is located in an area of cerrado on the Teaching and Research Farm of FEIS / UNESP. It was sampled seeds in 30 trees to determine the biochemistry and technological traits. The trees were also located per GPS apparatus, with objective of obtaining geographic coordinate and to analysis the genotype spatial structure from I Moran Index. The analysis of spatial autocorrelations, from I Moran index, indicated the tendency of a larger structure among trees near spatially. In another hand, trees distant spatially showed smaller similarity. The spatial structure was more visible in a ray of 353m.

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Mycobacterium fortuitum is a rapidly-growing species of bacteria, ubiquitous in the environment and related to important human mycobacterioses. It has been isolated from blood, abscesses, the endocardium and surgical and traumatic wounds. This mycobacterium is hard to treat, being recognized in the literature as resistant even to the drugs used in the treatment of tuberculosis. The objective of this study was to screen extracts prepared from plants of the Brazilian cerrado (extended savanna-like belt) with known activity against M. fortuitum, employing the Microplate Alamar Blue Assay (MABA) as the analytical method. Out of 26 extracts tested against M. fortuitum, the nonpolar extract of Quassia amara (in methylene dichloride) gave the best result (MIC 62.5μg/ mL), followed by the nonpolar extracts of Syngonanthus macrolepsis, Davilla elliptica and Turnera ulmifolia, with equal MICs of 125μg/ml. The polar extracts (in ethanol and methanol) obtained from the same plants were considered inactive, since the MIC values determined were above 500μg/mL and not significantly different from those of extracts from other plants, without known activity.

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There was evaluated the phenology and arthropods as well as the effect of weather on copaiba (Copaifera langsdorffii Desf.) (Leguminoseae). The emission of new leaves and inflorescences as well as the opening of them occurred in the rainy period. There were observed the higher diversity and abundance of insects, principally galling insects.

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The regeneration of plant communities from seed depends, to a large extent, on the capacity of the seed remaining viable in the soil. The viability and germination of artificially buried Psychotria vellosiana seeds in cerrado soil were studied, with the purpose of discovering some physio-ecological aspects of dispersed seeds and evaluating their potential to constitute a soil seed bank. Seed samples were placed in nylon envelopes and buried in the soil of a Cerrado reserve at two different depths and sites. Buried seeds were retrieved periodically and tested for germination along with dry-stored seeds. In general, there was a reduction in seed germination with storage time, both in soil and dry stored conditions, and in some assays exhumed seeds germinated faster than dry stored ones. In general the soil storage favoured seed viability of ungerminated seeds as compared to dry stored ones, with the seeds remaining partially viable after 10 months of storage. The lack of germination of viable seeds suggests that seeds showed true dormancy and/or required an extended time to germinate. It was observed that some seeds had germinated while buried and such in situ germination tended to increase with rainfall. The water availability in the soil might be a limiting factor for successful germination of P. vellosiana in the field, and the seeds may constitute a persistent soil seed bank in the cerrado as dispersed seeds remain viable in the soil until the following period of seed dispersal.

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Distribution and ecology knowledge of sandfly species is essential for epidemiology vigilance and risk determination for transmission of leishmaniasis. Sandfly trapping was carried out in a cerrado strictu sensu vegetation fragment in a rural area of Corumbataí Municipality, São Paulo State, Brazil, during July to November 2004. Two CDC light traps were used from 18h to 8h, once a month, resulting in 112 total hours of capture. During this period, 60 sandfly specimens of ten different species were sampled. The most abundant species and the one found in all captures was Pintomyia monticola totalizing 15 (25.0%) specimens, the second more abundant one was P. pessoai with 14 (23.3%) and the third one was Brumptomyia guimaraesi with 12 (20.0%) individuals collected. Other captured species were Psathyromyia aragaoi, B. avellari, B. brumpti, B. cunhai, P. bianchigalatiae, Evandromyia termitophila and Nyssomyia whitmani which corresponded to 19 (31.2%) specimens captured. Pintomyia pessoai and N. whitmani presence indicates transmission risk of American Cutaneous Leishmaniasis in the area.

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Neea theifera Oerted (Nyctaginaceae), Guapira noxia Linn. (Nyctaginaceae) and Hancornia speciosa Gomes (Apocynaceae) are plant species found in Brazilian Cerrado used popularly for the treatment of gastric ulcers. Here they are assessed for mutagenic activity by analysis of the reverse mutations induced in Salmonella typhimurium strains TA100, TA98, TA102 and TA97a, by extracts of the plants, with and without metabolic activation. Methanol and chloroform extracts of N. theifera and G. noxia and methanolic and aqueous extracts of H. speciosa were tested at five different concentrations. It was found that only the methanolic extract of H. speciosa exhibited a positive mutagenic effect, on strains TA98 and TA100 in the absence of metabolic activation. The phytochemical analysis of the species suggested that condensed tannins are the main compounds responsible for the observed effect.

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The high rate of mineralization of organic matter on savannah soils, which is reached fi ve times faster than in temperate regions, leads us to the challenge of electing the best system of management that maintains and/or increase it in soil, guaranteeing its quality and sustainability. In this sense the present research aimed to study the effects of green, organic and mineral manure on the chemical properties on the chemical properties of an Oxisol, on Savannah area, cultivated with cotton (Gossypium hirsutum) under conventional tillage and no-tillage in the pasture fi eld (Brachiaria decumbens) for 20 years. The experimental design was a randomized block design with split plots. The main plots consisted of two treatments: conventional tillage and no-tillage, and the subplots of six treatments: control (no fertilizer), mineral fertilizer recommended for the crop, according to the soil chemical analysis, organic fertilizer (cattle manure - 20 t ha-1), organic fertilizer (cattle manure - 20 t ha-1) + 1/2mineral fertilization recommended according to the analysis of soil, green manure-1 (Crotalaria juncea) and green manure-2 (Pennisetum americanum). There were studied the following soil chemical properties: P, OM, pH, K, Ca, Mg, Al, Al + H, S, exchange capacity cations and base saturation. The soil samples for the analysis were performed on layers of 0,00-0,05 m, 0,05-0,10 and 0,10-0,20 m. Then it came the following conclusions: the fertilization interfere in soil chemical properties and the preparation did not interfere, the cattle manure and its association with the mineral fertilizer caused increasing level elements in the soil, Crotalaria juncea and Pennisetum americanum did not infl uence on soil chemical properties.

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Mesoclemmys vanderhaegei is a Neotropical chelid lacking basic natural history studies. Based on a film made in December 2004, we describe the courtship behavior in this species. Field observations were conducted at Chapada dos Guimarães, Mato Grosso State, southwestern Brazil, in an oligotrophic stream amidst the savannah like Cerrado formation. We provide a schematic drawing of the behavioral sequences during courtship, as well as a flow diagram describing sequential responses of the female to the male behavioral patterns. Mesoclemmys vanderhaegei courtship behavior is similar to that described for other freshwater chelonians.