Considering the importance of studies in communities dynamics, especially in vegetation sites with anthropogenic disturbs as Caatinga of Northeastern Brazil, was evaluate the edge effect caused by the opening of a oil duct on the dynamics of plants in three physiognomies of Caatinga (open shrub, riparian shrub dense and shrub dense) over 15 months (May/2007, January/2008 and August/2008), taking into account the hypothesis that there are differences in the dynamics in areas near edge and more distant. In each situations were evaluated edge and interior, so much in terms of trees in five plots of 10×10 m contiguous as of regeneration of the plants in plots of 2×2 m. Were calculate mortality, recruitment and growth rates in the edge and interior. Most important differences in terms of edge and interior occurred in open shrub Caatinga. The largest fluctuations in the values of density and diameter occurred at the edge, which indicates that the opening of the duct caused greater interference in this situation.

The objective of present work was of classifying, consonant the Brazilian System, profiles of soils of ecosystems, as subsidies to evaluation of soil quality. The fieldwork was driven at the place Chã de Jardim, municipal district of Areia, PB, Brazil. They were open trenches, in different agrosystems - sabiá population (T1), of pinus (T2), and traditional cultivation-degraded area (T3), where they were made the description and it collects of soil materials for accomplishment of the chemical and physical analyses. The soils were classified in the Brazilian System of Classification of Soils. Being adopted an operational sequence, the profiles of respective areas were classified as: Entisol, Oxisol and Inceptisol In terms of quality of soil and starting from an arbitrated minimum indication, it was verified that profiles under pinus population and sabiá have position privileged in relation to degraded area. In spite of drop reservation of nutrients of profiles (dystrophic), the recycling in the soil under leguminous (T1) it is more efficient, since the reservation of nutrients in the Entisol is smallest among the compared sub superficiality.

The aim of this work was to evaluate methods for overcoming Jitirana's (Merremia cissoides) seeds dormancy. The treatments were: immersion of Jitirana's seeds in sulfuric acid during 20, 25, 30, 35, 40, 45, 50, 55 and 60 minutes and control (no treatment). The experiment was carried out in the completely randomized design, with ten treatments and four replications, with 20 seeds each. The variables evaluated were: germination percentage, germination speed index, medium time for germination, dry weight and height of seedling obtained 16 days after sowing. The immersion of seeds in sulfuric acid during 50 minutes is an efficient method to overcome dormancy and promotes germination, enabling quickly and greater Jitirana's seedling emergence.

This work evaluated the effect of two methods of determination of soil water (laboratory method and field method) and four levels of soil water availability (20; 40; 60 and 80%) on biomass of the aerial part, crop evapotranspiration, leaf area, plant height and yield in pit of herbaceous cotton plant, cultivar CNPA-7H. The randomized blocks experimental design was used in factorial scheme 2 x 4, with three replications. The determination of available soil water by the field method overcame the results of the studied variables in relation to the laboratory method and it represents more real conditions of the readiness of water for the cotton plant. The leaf area and the evapotranspiration, determined by field method, increased significantly with the levels of available soil water. The management with the available water of 61.61% by laboratory method promoted the maximum leaf area of 1755.4 cm2 and, with 74.4% of levels of available water, the maximum evapotranspiration was of 238 mm. There were earnings of 0.2 g of biomass per unit of levels of available soil water by field method; already by laboratory method the maximum biomass of 17.6 g was reached with the management of levels of available water of 62.9%. The best response for the cotton incomes in pit was given by field method with earnings in the income of 0.26 g for the field method and of 0.11 g for the laboratory method per unit of available soil water.

The objective of that work was to evaluate the influence of different soil mulching and doses of organic compost in the culture of the rocket. The experimental design was used in randomized blocks, in splitplot arrangement with four replications. The plot corresponded to the soil mulching (no-tillage with living mulch of Arachis pintoi, living mulch of native weed, straw mulch of native weed and conventional tillage without mulching). The plots represent the doses of organic compost (10, 20 and 30 t ha-1 in the dry compost). The variables analyzed were yield, commercial fresh matter, and dry matter of the aerial part. The dose of 30 t ha-1 provided the largest yield values and commercial fresh mass for the conventional system and straw mulch. The dose 20.49 t ha-1 increased yield and commercial fresh mass for A. pintoi mulch. The dose 20.85 t ha-1 showed greater increase in yield and commercial fresh mass for the live native weed. The tillage and straw mulch presented higher yield values for all the studied doses. The dose of 23.1 t ha-1 it promoted the largest dry mass of the aerial part. The tillage and no-tillage with straw mulch it contributed with the largest dry matter of the aerial part.

Phylogeography has become a powerful approach for elucidating contemporary geographical patterns of evolutionary subdivision within species and species complexes. The aim of this paper was to evaluate the extracted quality of DNA and amplification of noncoding chloroplast DNA for phylogeography studies in Ficus bonijesulapens. The comparative analysis of protocol DNA extraction was based in the CTAB method and protocol from Mogg and Bond. DNA samples were assessed for successful PCR amplification of universal primers for the amplification of noncoding regions of cpDNA. Amplified DNA was separated by electrophoresis, stained with ethidium bromide and photographed under UV light. The protocol Moog e Bond produced the best DNA quality. This method will be used because it produces a high quality DNA in a short time and is less expensive. The primers HA, SG, BF, Q16, F32, FV, DT, CS and JA provided the strongest support for the inferred phylogeography, genetic diversity centers and for successful management in tree-conservation programmes.

Lettuce has highlight as an important crop for human consumption, to having good flavor and important nutritional characteristics and potassium is one of the main nutrients that crop. This work aimed to evaluate the influence of potassium in morphological and physiological lettuce responses in South of Tocantins State. The experimental design was randomized block in factorial scheme of 4 x 6 with three replications. Four levels were evaluated of K2O: 0; 100; 200 and 300 kg ha-1 in six development stages: 15; 22; 29; 36; 43 and 50 days after emergency. Was determine the specific leaf area, net assimilation rate, relative growth rate and abso-lute growth rate, as well as the leaf, stem and root weight. During the duration of the experiment occurred high temperatures that caused a physiological disorder known as tipburn, which compromises calcium uptake by the plant. The potassium levels did not influence the morphological and physiological responses of lettuce as well did not significant differences among levels for leaf, stem and root weight. The partition of assimilates in the plants was influenced by crop management whit significant variation among evaluation times.

This work aimed to evaluate the influence of the substrate and the level of moisture on the germination of 'pau-de-balsa'. Before installation of the germination test, seeds were immersed in hot water at 80 °C until cooling to overcome dormancy. We evaluated the substrate sand and vermiculite, moistened with water volumes equivalent to 60%, 70%, 80% and 90% of the capacity to retain water. The experimental design used was completely randomized in a 2 x 4 factorial with four replicates of 20 seeds. The effects of treatments were compared for germination percentage, speed index and average time of germination. The seeds had higher germination in sand substrate, and the moisture level of the substrate does not affect the variables analyzed.

This work aimed to evaluate the effect of cut height on jurema-preta control. Thus, two trials were carried out, one in September 15th and other in December 15th of 1997. The experimental area had 1,400 m². Treatments were the height cuts of 25; 50; 75 and 100 cm from the soil. Evaluations were done when more than half of plants were showing 50% of their regrowth with a diameter of 0.7 cm. The experimental design was in randomized blocks with split-plot, being the height cut the parcel and the cut the sub-parcel. In the first trial and at the end of the 3rd cut, the higher mortality of 84.6% was found among plants cut at 75 cm and the higher number of regrowth was observed in plants cut at 100 cm, but the stem diameter was not affected by treatments. In the second trial and at the end of the 3rd cut, the higher mortality of 50% was found among plants cut at 100 cm and the other variables were not affected by cut height. The control of jurema-preta may be done in September, cutting the plants at 75 or 100 cm from the soil and always cutting the regrowth plants when they reach 0.7 cm of diameter. The jurema-preta control by standardization cut in December was inefficient regardless the cut height.

The aim of this study was to evaluate silicon (Si) and two phosphorus (P) extraction methods in "Latossolos" under corn and sorghum. The experiments were conducted in green-house, in a completely randomized, with corn for the 5x2x2 factorial arrangement, consisting of five P rates (0, 96, 192, 288 and 480 mg dm-3) in the absence and the presence of 300 mg dm-3 of slag in two "Latossolos" and four replicates, while for sorghum the experimental design was 5x2, and is used only one soil. The experimental plots were subjected to two incubation periods, the first with slag (only half of the plot) and then with lime. In the first experiment two plants were cultivated corn pot for 45 days and then ten plants of sorghum for 60. After the experiments took place the collection of plants being evaluated for plant height, stem diameter and dry weight of maize shoots and just shoot dry matter of sorghum, the levels of Si and P in samples soil and plants. The medium texture soil showed better correlations of Si and P. For the Olsen P method as both the Mehlich 1 had good correlation. Sorghum showed higher correlation coefficients than corn.