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 study was aimed to adjust probability distributions to a data series of maximum and minimum daily air temperature of Iguatu city in different periods of time, for the purpose of observe that the distributions under study has a better performance and has recommended its use to estimate the probability of occurrence of the estimated values of maximum and minimum air temperature. For the adjustment the data in distribution of frequency were used six probability distributions: Beta, Gamma, I Gumbel, Log-Normal, Normal, and Weibull. Through the adherence tests of Kolmogorov-Smirnov at 20% of significance and Chi-square at 5%, the distributions Normal Log-normal and have a better fit to the data for all scales analyzed, recommended the use of normal function by ease the estimation of its parameters and probabilities.

Through this research work, evaluating the chemical-bromatologic composition of in natura sugar cane as related to hydrolysis with whitewash. The work was conducted in the Forage Culture Sector of the Animal Science College at José do Rosário Vellano University (UNIFENAS), campus of Alfenas (MG). The experimental design utilized was the completely randomized in a factorial arrangement 4x5, four doses of whitewash were studied (0.0; 0.5; 1.0 and 2.0% on the basis of natural matter) in five times aerobic exposure (0, 6, 12, 24 and 48 hours), with four replicates. The addition of whitewash to sugar cane promoted lower temperatures till 12 hours of storage, from this point on, there no further effects of whitewash upon temperature control. The content of dry matter and ashes increased linearly with addition of whitewash, while protein content decreased. Whitewash promote no fall in the contents of water-neutral detergent-insoluble fiber and lignin, nevertheless, the contents of acid detergent insoluble fiber decreased, with more forceful when using 0.5 and 2.0% of whitewash. The use of whitewash in the hydrolysis of sugar cane alters the chemical bromatologic composition, however, the use of this additive is unjustified, because is not effect positive on the fiber content. The sugar cane in natura and hydrolyzed present the best composition immediately after the desintegration.

The callus culture facilitates the study of factors involved in somatic embryogenesis, technique that allows the production of embryos in vitro from somatic tissue, making the propagation possible of elite plants and constituting an important tool in breeding programs. The objective was to analyze the influence of growth regulators on the formation of callus on cotton cultivars BRS Araripe and BRS Seridó. In the Laboratory of Tissue Culture of Embrapa Algodão, for the induction and proliferation of callus, hypocotyledonary segments were cultured on MS medium supplemented with phytoregulators NAA, KIN and 2,4-D. For the induction of embryogenic callus, it was used redifferentiation medium, with no phytoregulators. Data were analyzed according to the nonparametric chi-square test, being verified high number of potentially embryogenic callus, with a friable consistence and cream-greenish coloration. In the treatment with addition of NAA and KIN was observed the formation of embryogenic callus of BRS Seridó. The dependence of the genotype is a major problem for the low frequency of somatic embryogenesis in cotton that has been achieved in a few cultivars; it is necessary to study in other varieties for the definition of appropriate protocols in this process.

In this work, the aim was to evaluate the performance of Irrigameter in the management of the irrigation water, led in the culture of the bean plant, comparatively to the use of the methods standard of stove, tensiometers, Bouyoucos, automatic meteorological station and pan Class A. Irrigameter was adjusted to the soil characteristics, culture of the bean and irrigation equipment to confection the management ruler. For direct estimation of the evapotranspiration of the culture of the bean plant in your development stadiums, Irrigameter operated inside with heights of the levels of water of the evaporatório same to 2, 3 and 5 cm, corresponding to the stadiums of initial development, vegetative development and flowering, respectively. The humidity obtained by the standard method of stove it was adopted as reference in the comparisons of the irrigation depth. Irrigameter can be used in the management of the irrigation to determine the consumption of water directly for a culture, in any development stadium; the methods that estimate the evapotranspiration of the culture overestimated the irrigation depth recommended by the standard method of stove, happening behavior contrary with the ones that determines the current humidity of the soil.

Two main floristics groups of the family exist in the Caatinga with different composition happening in two types of substrata: (1) in areas of sedimentary soil (2) in derived areas of the crystalline embasement. Due to the importance of Leguminosae in the biome, an inventory floristic of a defined area was accomplished by the Ministry of the Environment as priority for researches you inform in the Caatinga of the Municipal district of Mirandiba and an analysis of similarity of the flora with the one of other areas of the Brazilian Northeast. Trips were accomplished in the period of March from 2006 to July of 2007 for collection of botanical material. The floristics relationships were appraised for the analysis of UPGMA and PCO starting from the indexes of similarity of Sørensen. 75 species were registered distributed in 39 genera representing 25% of the leguminous mentioned already for the Caatinga. Fence 25% is considered endemic of the Caatinga. The similarity analysis showed the formation of two different groups: The group [A] with similarity of 20% it was established for the Caatinga on sandy soils. The group [B] with similarity of 27% it included the Caatinga on derived soils of the Pre-Cambrian crystalline embasement. Comparing the analyses obtained by the methods UPGMA and PCO, it was verified that the formation of the group [A] and their subgroups were common to the two methods. Already the formation of the group [B] it was not very clear in PCO.

The thermo-reflective and black screens was used for shading for plants and they has private properties that improve the microclimate conditions, it was aimed to evaluate the growth and yields in hydroponic lettuce production (Lactuca sativa L, cv. Olinda), under effect of the thermo-reflective with different percentages of attenuation of the solar radiation. The treatments were and thermo black screens 50% with four different percentages of attenuation of the solar radiation, being meshes 40, 50, 60 and 70%. It was observed significant differences in function of the treatments for all the analyzed characteristics number of leaf, diameter of stem, fresh and dry matter biomass, leaf area and distances of internodes. The meshes thermo-reflective 40 and 50%, it had provided better development for lettuce, in relation to expression of the economical characteristics, being suitable to supply shading in greenhouse conditions at Northeastern semi-arid areas. However, it's improved the most control of the solar radiation, temperature and relative humidity, with micro weather conditions the best for growth and yields of Lettuce.

Concerning the different plant physiognomies of Brazilian semi-arid, the riparian vegetation is the least studied. With reference to this, there is a gap in comprehension of the influence of environments heterogeneity on the flora distribution. In order to evaluate the richness and species composition in distinct environments along a stretch of riparian vegetation of the Pajeú river, was performed a botanical survey in the municipality of Floresta, Pernambuco state. Samples were collected in six hectare. Were identified 78 species in 39 families in four environments: the fluvial terrace, the riverside, the small elevation and the tableland. Families with the greatest number of species were Leguminosae (sensu Engler) and Euphorbiaceae, similar to those reported in other Caatinga surveys. 52% of species collected were herbs. As expected, there were floristic differences between the gradient along the fluvial terrace to tableland, as a function of environmental heterogeneity. The tableland had the highest species richness while the fluvial terrace the lower.

In Northeastern Brazil peanut is an important culture due to its high palatability, nutritional value, grain high oil content and for being an additional and/or alternative source of income for small regional farmers. However, production is insufficient, primarily due to low yield, lack of use of adequate cultivars and inadequate management. Therefore, an experiment was carried out (March/June, 2008), at the Universidade Federal Rural do Semi-Árido (UFERSA) (Semi-arid Rural Federal University), in Mossoró, RN (Rio Grande do Norte State, Brazil) experimental station, to evaluate yield of 2 creeping peanut cultivars (Runner IAC 886 and IAC-Caiapó), grown in 2 row spacings (0.5 m and 0.9 m). In a complete randomized block design treatments were allocated in a 2 x 2 factorial (2 cultivars x 2 row spacings), with 4 replications. Production components and yield were evaluated (number pods plant-1, number seeds meadow-1, 100 seed weight, pod yield, percentage yield almonds and straw yield). Cv. Runner IAC 886 showed higher yield than cv Caiapó, in both row spacings (0.5 m = 5,169 kg ha-1 and 0.9 m = 4,264 kg ha-1) mainly due to the number of pods plant-1. Row spacings affected both cultivars. Runner IAC 886 showed higher yield of pods at the 0.5 m spacing (5,897 kg ha-1) and Caiapó in the 0.9 m spacing (4,264 kg ha-1). Straw yield was higher in the lower row spacing cultivation.