Soluble phosphate accumulation by Aspergillus niger from fluorapatite

In order to determine conditions that may provide greater solubilization of insouluble phosphate, the fungus Aspergillus niger was grown in a stationary culture containing modified citrate medium supplemented with 800 mg fluorapatite per litre. Solubilization of insouluble phosphate increased with fungal growth, reaching a maximum after 11 days of culture. Soluble phosphate levels were correlated with pH of the culture medium but not with titratable acidity values, probably due to the metabolic activity of the fungus resulting from consumption of sugar in the culture medium. Fructose, glucose, xylose, and sucrose were the carbohydrates that favoured fluorapatite solubilization the most when compared with galactose and maltose. Although increasing fructose concentrations in the culture medium favoured mycelial growth, increased total acidity and a fall in pH, soluble phosphate levels were reduced, probably owing to consumption by the rapidly growing fungus. Among the nitrogen sources tested, ammonium salts favoured the production of larger amounts of soluble phosphate than organic nitrogen (peptone or urea) or nitrate, corresponding to the lowest pH and highest titratable acidity values obtained. © 1988 Springer-Verlag.

Nickel chloride: potential accumulation from the airway. Toxicokinetics in rats.

The rate removal of nickel from the airway was measured in vivo. Removal in vivo was studied by intratracheal injection of nickel chloride solutions. Regardless of time after injection, the lungs and heart retained the greatest concentration of nickel and 40 days after 1.68 mumol administration they were the organs where nickel was still significantly measurable. The slow removal of nickel may indicate the presence of high affinity binding sites in the lung. Nickel can interact with others metals, such as copper and zinc, so that nickel exposure may have public health implications.

Recuperação de povoamento de Eucalyptus urophylla com aplicações de nitrogênio, potássio e calcário dolomítico

A plantation of Eucalyptus urophylla, established in 1984 on a Quartzpsamment Soil, at Altinopolis, São Paulo State, presented in 1989 an medium increment of the cylindrical volume of the trees of 13.97 m 3/ha/year and also showed deficiency symptoms of potassium, calcium and magnesium. At 4.33 years after planting were applied two doses of nitrogen (0 and 10 g/tree of N), potassium (0 and 20 g/tree of K 2O) and of dolomitic lime (0 and 500 g/tree), combined in a randomized block design arranged in a factorial way (2 × 2 × 2), with four replications, in order to study the recuperation of the tree growth rate. Evaluations of the trees growth were performed at 4.33, 5.67, 6.75 and at 7.58 years when cutting the plantation was done. The soil fertility and leaf concentrations of N, K, Ca and Mg were analyzed before and after the application of the treatments. The accumulation and distribution of biomass and of these nutrients in the tree components and in the litter, and the economic studies referring to the volumes of wood were also evaluated 7.58 years after planting. Potassium fertilization increased the mass of potassium in stemwood, stembark, foliage, fruits and litter, but the increase was greater in foliage and in the stembark. Liming increased the mass of magnesium in stemwood, stembark, foliage and litter, but the increase was greater in the litter. There was no isolated effect of nitrogen fertilization. The growth rate of trees was recovered with the potassium application, which increased the mean annual increment (MAI) of cylindrical volume from 13.85 m 3/ha/year without fertilizer to 16.82 m 3/ha/year. At 7.58 years after planting, there was observed an effect of the N x K x dolomitic lime interaction in the wood production. In the absence of nitrogen and dolomitic lime, the application of potassium increased the real volume of 43% and there was a gain of US$ 86.79/ha.

Root growth and nutrient accumulation in cover crops as affected by soil compaction

Crop rotation using cover crops with vigorous root systems may be a tool to manage soils with some degree of compaction. Root and shoot growth as well as nutrient accumulation by summer species suitable for crop rotation in tropical areas were studied at different subsoil compaction levels. Crotalaria juncea (Indian hemp), Crotalaria spectabilis (showy crotalaria), Helianthus annuus (sunflower), Pennisetum americanum (pearl millet) and Sorghum bicolor (guinea sorghum) were grown for 40 days in pots 33.5 cm high with 10 cm internal diameter. Soil in the pots had uniform bulkdensity of 1.25 Mg m-3 for the top and bottom 15 cm sections. Bulk densities of 1.31, 1.43, 1.58 and 1.70 Mg m-3 Were established in the 3.5 cm middle section. H. annuus and P. americanum had the highest early macronutrient accumulation. The grasses S. bicolor and P. americanum yielded twice as much shoot dry matter as the other species. Root growth generally decreased with increasing soil bulk density with C. spectabilis less affected than other species. Although the grasses were more sensitive to high soil penetration resistance, they showed higher root length densities at all compaction levels. P. americanum had the highest potential to be used as cover crop due to its high root density at high soil penetration resistances, vegetative vigour and ability to accumulate macronutrients. © 2002 Elsevier Science B.V. All rights reserved.

Nutrients foliar content for high productivity cultivars of guava in Brazil

Commonly grown in tropical and sub-tropical regions, guava (Psidium guajava L.) is an important fruit crop of Brazil. It is cultivated on a large scale in São Paulo state, and covers about 6,500 hectares. As a result of the guava selection program developed at FCAV/UNESP, two new cultivars were created: 'Rica' and 'Paluma' with a high productivity, and also with higher nutritional requirement. Leaves analysis has become a powerful tool in mineral-nutrition research with fruit crops, not only to determine response to different nutrients, but also for diagnostic techniques in making fertilizer recommendations and assessing deficiency symptoms. Nutrient composition of the leaves varies depending on the leaf maturity, tree age, variety and nutrient supply. For the interpretation of analytical values, selection of the index tissue is important. The results of experiments conducted in the field during 1989-2000 were studied. The nutritional status was evaluated by annual leaf sampling, carried out at full bloom. Recent fully developed leaves, corresponding to the third pair (with the petiole) were collected, starting at the end of the branch, all around the tree, at a height of 1.5 m from the soil, with a total of 30 leaf pairs per sample. The yield was evaluated by weighing all the fruits in the useful area of each lot. Foliar chemical analysis showed excellent correlation with the fruit production. Through the results it was verified that the maximum yield was associated to the following levels: N = 22-26; P = 1.5-1.9; K = 17-20; Ca = 11-15; Mg = 2.5-3.5; S = 3.0-3.5 g kg -1; B = 20-25; Cu = 10-40; Fe = 50-150; Mn = 180-250; Zn = 25-35 mg kg-1 DW in the leaves of the 'Rica' guava and to N = 20-23; P = 1.4-1.8; K = 14-17; Ca = 7-11; Mg = 3.4-4.0; S = 2.5-3.5 g kg-1; B = 20-25; Cu = 20-40; Fe = 60-90; Mn = 40-80; Zn = 25-35 mg kg-1 DW in the leaves of the 'Paluma' guava.

Heavy metal nutrients in tomato plants cultivated in soil amended with biosolid composts

The use of biosolids in horticulture could contribute to recycle residues produced by men. This study analyzed concentrations of Cu, Mn and Zn in the compost during fermentation, in the soil amended with the composts and in the tomato plant materials. Five composts were produced using sugar-cane bagasse, biosolid and cattle manure in the proportions: 75-0-25; 75-12.5-12.5; 75-25-0; 50-50- 0 and 0-100-0 (composts with 0; 12.5; 25; 50 and 100% biosolid), respectively. These composts were used in an experiment with 6 treatments (the 5 composts and a control with mineral fertilization) in a design of randomized blocks with a split plot design. The control and the treatment of 0% biosolid received inorganic nitrogen. All the treatments received the same amount of N, P and K. Two tomato plants were cultivated in each 24 L pot, in a greenhouse at the Technology Department of the Faculdade de Ciências Agrárias e Veterinárias of the Universidade Estadual Paulista in Jaboticabal County, São Paulo State, Brazil. The concentrations of Cu, Mn and Zn were evaluated in the compost 7, 27, 57, 97 and 127 days after composting began, in the soil 0 and 164 days after the compost applied, and in the plants. Compost, soil and plant samples were subjected to digestion with HNO3, H 2O2 and HCl and the metals were determined by AAS. There were positive and significant correlations between Mn in the compost and Mn uptake by the plant (0.46 p>0.05), and between Zn in the compost and Zn concentration in the plant (0.78 p>0.05). Cu, Mn and Zn concentrations increased during composting. The biosolid in the compost supplied Cu and Zn to tomato plants, and the cattle manure supplied Mn to the plants.

Matéria seca, concentração e acúmulo de nutrientes em mudas de Eucalyptus grandis em função da idade

E grandis seedlings of Bofete progeny, cultivated in nurseries of Eucatex Florestal, were collected at ages of 55, 69, 83, and 97 days, separated into leaves, stem, and roots. The seedlings were then placed in identified paper bags, and oven-dried until weight became constant. They were then weighed and chemically analyzed for the determinate of dry matter production, concentrations and accumulation of N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, and Zn in the several seedling ages. The distribution of total dry matter weight complied with the following descending order: leaf > stem > roots. Conversely to expectations, the highest concentrations of nutrients occurred in leaves for N and Mn only. Seedling hardened process resulted in N and S deficiency. The sequence of macronutrient concentration in seedlings at the time of shipment was the following: leaf > root > stem for N; root = stem > leaf for P; leaf = root = stem for K; stem > root > leaf for Ca; root > leaf > stem for Mg and S. All macronutrient concentrations in organs decreased with age, except for Ca. Concentrations of Cu, Fe, and Zn in all seedling specimens decreased with age. The sequence of micronutrient concentrations in seedling specimens at the time of shipment was the following: root >stem = leaf for B; root > stem > leaf for Cu and Fe; root > leaf > stem for Zn, and leaf > stem > root for Mn. At the time of shipment, at 97 days of age, K was the most extracted macronutrient of all, followed in a descending order by Ca, N, Mg, P, and e S. At the end of the seedling production rotation, Mn was the most extracted micronutrient, followed by Fe, Zn, Cu, and B.

The relationship between onset of blood lactate accumulation, critical velocity, and maximal lactate steady state in soccer players

The objective of this study was to analyze the validity of the velocity corresponding to the onset of blood lactate accumulation (OBLA) and critical velocity (CV) to determine the maximal lactate steady state (MLSS) in soccer players. Twelve male soccer players (21.5 ± 1.0 years) performed an incremental treadmill test for the determination of OBLA. The velocity corresponding to OBLA (3.5 mM of blood lactate) was determined through linear interpolation. The subjects returned to the laboratory on 7 occasions for the determination of MLSS and CV. The MLSS was determined from 5 treadmill runs of up to 30-minute duration and defined as the highest velocity at which blood lactate did not increase by more than 1 mM between minutes 10 and 30 of the constant velocity runs. The CV was determined by 2 maximal running efforts of 1,500 and 3,000 m performed on a 400-m running track. The CV was calculated as the slope of the linear regression of distance run versus time. Analysis of variance revealed no significant differences between OBLA (13.6 ± 1.4 km·h-1) and MLSS (13.1 ± 1.2 km·h-1) and between OBLA and CV (14.4 ± 1.1 km·h-1). The CV was significantly higher than the MLSS. There was a significant correlation between MLSS and OBLA (r = 0.80), MLSS and CV (r = 0.90), and OBLA and CV (r = 0.80). We can conclude that the OBLA can be utilized in soccer players to estimate the MLSS. In this group of athletes, however, CV does not represent a sustainable steady-state exercise intensity. © 2005 National Strength & Conditioning Association.

Comparative studies of the sample decomposition of green and roasted coffee for determination of nutrients and data exploratory analysis

The contents of some nutrients in 35 Brazilian green and roasted coffee samples were determined by flame atomic absorption spectrometry (Ca, Mg, Fe, Cu, Mn, and Zn), flame atomic emission photometry (Na and K) and Kjeldahl (N) after preparing the samples by wet digestion procedures using i) a digester heating block and ii) a conventional microwave oven system with pressure and temperature control. The accuracy of the procedures was checked using three standard reference materials (National Institute of Standards and Technology, SRM 1573a Tomato Leaves, SRM 1547 Peach Leaves, SRM 1570a Trace Elements in Spinach). Analysis of data after application of t-test showed that results obtained by microwave-assisted digestion were more accurate than those obtained by block digester at 95% confidence level. Additionally to better accuracy, other favorable characteristics found were lower analytical blanks, lower reagent consumption, and shorter digestion time. Exploratory analysis of results using Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) showed that Na, K, Ca, Cu, Mg, and Fe were the principal elements to discriminate between green and roasted coffee samples. ©2007 Sociedade Brasileira de Química.

Plant nutrients in a degraded soil treated with water treatment sludge and cultivated with grasses and leguminous plants

The objective of this work was to evaluate rates for applications of water treatment sludge (WTS) as a nutrient source for grasses and leguminous plants cropped in a soil degraded by tin mining in the Amazon Region (Natural Forest of Jamari, Rondonia State, Brazil). The treatments consisted of three rates of nitrogen supplied by WTS (100, 150 and 200 mg kg -1 soil), five combinations of plants, two controls (absolute control, without fertilization; and chemical control, soil+lime+chemical fertilizers). WTS modified the contents of macro and micronutrients in the degraded soil, but it was not, as used in the present study, sufficient for the rehabilitation of the degraded area. © 2006 Elsevier Ltd. All rights reserved.

Protein levels for heat-exposed broilers: Performance, nutrients digestibility, and energy and protein metabolism

Heat stress causes significant economic losses on broilers production due to poorer performance and carcass quality. Considering that protein has the highest heat increment among nutrients, it has been suggested that protein levels should be reduced in diets for heat-exposed broilers. Nevertheless, there are no conclusive results on the benefits of such practice, and further studies should be performed to elucidate some reported discrepancies. Thus, a trial was carried out to evaluate the effects of dietary protein levels (17, 20 and 23%) and environmental temperature (22 and 32°C) on the performance, nutrients digestibility, and energy and protein metabolism of broiler chickens from 21 to 42 days of age. Nutrients digestibility was determined by total excreta collection, and energy and protein metabolism was evaluated by comparative slaughter method. It was concluded that (1) heat exposure impairs broilers performance and increases nitrogen excretion, but do not change nutrients digestibility; (2) high-protein diets are technically feasible and promotes lower heat production for broilers reared under thermoneutral or hot environments, however, high-protein diets increases nitrogen excretion. © Asian Network for Scientific Information, 2007.

Acúmulo de macronutrientes por duas cultivares de cebola produzidas em sistema de semeadura direta

Economically, onion is the third more important vegetable in Brazil. As a consequence of the increasing by use of new hybrid varieties, the nutritional management of the crop needs to be adequately known. This research was carried out in São José do Rio Pardo, São Paulo State, Brazil, from March 7 to August 8, 2004. The objective was to quantify, under field conditions, the accumulation of macronutrients by onion cultivars established by direct sowing. The experimental design was in randomized blocks with three replicates. The cultivars studied were Optima and Superex. Samples were taken at 30, 50, 70, 90, 110, 130 and 150 days after sowing. With population of 354,000 plants ha -1 and productivity estimated in 64.8 t ha -1, 'Optima' extracted on 150 days after sowing: 78.77, 13.04, 75.77, 59.09, 11.70 and 24.38 kg ha -1 of N, P, K, Ca, Mg and S, respectively, and 'Superex', for the same plant population, and productivity at 72 t ha -1, 64.68, 10.33, 68.28, 65.58, 13.03 and 24.74 kg ha -1 of N, P, K, Ca, Mg and S, respectively. The Optima hybrid exported through its bulb about 49.17% of N, 60.60% of P, 61.16% of K, 41.15% of Ca, 43.56% of Mg, and 47.18 of S, the equivalent to 38.73, 7.90, 46.34, 24.32, 5.10 and 11.51 kg ha -1, respectively. The Superex hybrid exported through its bulb about 44.29% of N, 55.85% of P, 62.54% of K, 35.71% of Ca, 31.82% of Mg, and 48.80% of S, the equivalent to 28.65, 5.77, 42.70, 23.42, 4.15, and 12.07 kg ha -1, respectively.

Crescimento e acúmulo de nitrogênio e potássio pelo melão pele de sapo fertirrigado

With the objective of obtaining dry matter curves, and nitrogen and potassium accumulation in Piel de Sapo melon (Cucumis melo L.) hybrid Sancho, an experiment was conducted in Mossoró - RN in a randomized blocks design with three repetitions. Treatments consisted of doses in kg ha-1 of nitrogen: 0, 91, 140 and 184 and potassium: 0, 174, 260 and 346; which were applied by fertigation in depths of 281, 349 and 423mm. Stems, leaves and fruits were harvested 5 times at 28 to 70 days after transplantation, in intervals of 10 days for analyses of aerial dry matter, nitrogen, and potassium accumulation. Doses higher than 140 and 260 kg ha-1 of N and K respectively, did not induce greater accumulation of these nutrients increasing levels throughout the plant cycle. Nitrogen doses of 91 and 140 kg ha-1, potassium doses of 174 and 260 kg ha-1 as well as depth of 348mm provided higher accumulation of potassium in the plant.

Asset accumulation by the middle class and the poor in Latin America: political economy and governance dimensions

Includes bibliography