Molibdênio via semente e nitrogênio em cobertura no feijoeiro irrigado em solo de cerrado

O nitrogênio é o nutriente mais exigido pelo feijoeiro e seu metabolismo pode ser seriamente prejudicado pela deficiência de molibdênio. Conduziu-se este trabalho, com o objetivo de avaliar o efeito da aplicação de molibdênio via semente e nitrogênio em cobertura nas características agronômicas e produtividade do feijoeiro 'BRS Pontal' irrigado, cultivado em Neossolo Quartzarênico, no município de Cassilândia, MS. O delineamento experimental utilizado foi o de blocos casualizados, no esquema fatorial 4x2, com quatro repetições. Os tratamentos foram constituídos pela aplicação ou não de Mo (80 g ha-1) via semente e quatro doses de N (0, 30, 60 e 120 kg ha-1), em cobertura aos 16 dias, após a emergência, na forma de uréia. A aplicação de Mo via semente aumentou o índice relativo de clorofila, o número de vagens por planta, a massa e a produtividade de grãos no feijoeiro, principalmente com o uso de altas doses de N em cobertura. O índice relativo de clorofila, o número de vagens por planta, a massa e a produtividade de grãos do feijoeiro foi aumentada linearmente pela aplicação de até 120 kg ha-1 de N em cobertura. O fornecimento de Mo via tratamento de semente aumentou a eficiência de utilização do N pelo feijoeiro.

Nutritionally induced changes in endosperm of shrunken-1 and brittle-2 maize kernels grown in vitro

Although mineral nutrition affects maize (Zea mays L.) yield by controlling starch deposition in kernels, the mechanisms involved are largely unknown. Our objectives were to examine this relationship by nutritionally and genetically altering starch production in the endosperm. Kernels of W64A and two starch-deficient mutants, shrunken-1 and brittle-2, were grown in vitro with varying supplies of N (0-50 mM) or P (0-6 mM) to produce different degrees of endosperm starch production, and the levels of enzyme activities and metabolites associated with carbohydrate and N metabolism were examined. In vitro grown kernels exhibited the expected starch phenotypes, and a minimum level of media N (25 mM) and P (2 mM) was required for optimal growth. However, increasing the availability of N or P could not overcome the genetically induced decrease in starch deposition of the mutants. Nitrogen deficiency enhanced sugar accumulation, but decreased amino acid levels, soluble protein, enzyme activity, starch synthesis, and endosperm dry weight. Phosphorous deficiency also decreased starch production and endosperm dry weight, but with only a minimal effect on the activities of ADP-glucose pyrophosphorylase and alanine transaminase. Genotypic differences in endosperm starch, and the increases induced by N and P supply, Here closely associated with the level of endosperm N, but not endosperm P. Thus, while both N and P are crucial for optimal yield of maize grain, they appear to act by different means, and with different importance in governing starch deposition in the endosperm.

Manganês no solo, sua avaliação e toxidez de manganês em soja

Two experiments were carried out in pots with a Dusky Latossol showing a 15% base saturation. In the first experiment dolomitic limestone was applied to reach 45, 60, 75 and 90% of base saturation. In the second, MnSO4 was applied in rates of 30, 60, 90 and 120 ppm,and base saturation was raised to 70%.Soybean plants cv. IAC-9 were grown up to R6, when dry matter production and manganese accumulation were evaluated. Soybean responded to liming up to 60% base saturation, as Mn availability and evantualy Mn absorption were decreased to non-toxic levels. Mn applied to a reclamed soil up to 120 ppm was not enough to cause toxicity to soybean cv IAC-9. All of the chemical extractors (Ammonium Acetate, DTA, Mehlich and H2SO4) showed modification in Mn availabity in soil but were not definitely related to Mn absorption and dry matter production.

Gas exchange in lisianthus plants (Eustoma grandiflorum) submitted to different doses of nitrogen

The effect of different doses of nitrogen (N) on gas exchange, relative chlorophyll (Chl) amount, and the content of N in the aerial biomass of lisianthus was evaluated. The treatments consisted of six different concentrations of N (50, 100, 150, 200, 250, and 300 g m(-3) noted as N-50, N-100, N-150, N-200, N-250, and N-300, respectively), applied through the fertirrigation technique. N-250 and N-300 induced increase in the contents of foliar Chl and N in the aerial biomass, that in turn contributed to an increase of photosynthetic activity in lisianthus.

Resposta do abacaxizeiro 'Vitória' a doses de nitrogênio em solos de tabuleiros costeiros da Paraíba

Informations about fertilization and mineral nutrition of the new fusariosis-resistant pineapple cultivars are still scarce, despite the importance of this crop. The purpose of this study was to evaluate the effect of increasing doses of N on fruit yield and quality of the pineapple cultivar 'Vitoria' grown on a 'Humiluvico Espodossolo' in the region of Tabuleiros Costeiros, in the state of Paraiba. The experiment was arranged in a randomized block design, using five N doses (100, 200, 300, 500 and 600 kg ha(-1)N, as urea) applied 60, 180 and 270 days after planting (dap) with three replications. The following variables were evaluated: length and fresh matter of the 'D' leaf; contents of N, P and K in the portions with and without chlorophyll, 300 and 420 dap; average weight, yield, physical properties (fruit weight, length and medium diameter; crown weight and length) and chemical properties (pH, soluble solids -SS, titrable acidity - AT, and the SS/AT ratio) of the fruits at harvest. Increasing N doses linearly increased length and fresh matter of the 'D' leaf and N content and decrease both P and K contents of the chlorophyll portion 300 dap, but did not affect nutrient contents 420 dap; in the chlorophyll-free portion. Increasing N doses, also, led to an increase in K contents 320 dap, but to reductions 420 dap. Individual fruit weight and total yield increased with increasing N doses, as maximum values of 1.0 kg and 37.9 t ha(-1) were estimated at doses of 409.0 and 439.0 kg ha(-1) N, respectively. The N doses did not affect the fruit quality properties, which were compatible with the characteristics described for this cultivar.

Teores foliares de nutrientes, índice relativo de clorofila e teores de nitrato e de potássio na seiva do pecíolo na videira 'Niagara Rosada

A nutritional survey was carried out in 93 vineyards of the wine regions of Jundiai, Sao Miguel Arcanjo and Jales (state of São Paulo-Brazil), aiming to compare the nutrient concentration in leaf samples, the concentration of nitrate and potassium in the petiole sap and the relative chlorophyll index (IRC) of 'Niagara Rosada' vineyard. Leaves, blade and petiole in full bloom vines were sampled in 20 plants selected from each vineyard, and evaluations of the IRC in the leaf blade and the levels of NO3-and K in the petioles sap were realized. Macro and micronutrients concentrations were measured in leaf samples. The sampled vineyards were grouped by region of study, and each vineyard was considered as a replicate sample, totaling 45, 24 and 24 repetitions, in Jundiai, Sao Miguel Arcanjo and Jales, respectively. Sampled vineyards from the Jales region showed higher leaf concentrations of P, K, Ca, Mg, S, Fe and Mn, and also higher IRC and levels of nitrate and potassium in the petiole. These differences were related to the different rootstocks used, which were 'IAC 766', 'IAC 572' and 'Riparia of Traviu', respectively, for Jundiai, Jales and Sao Miguel Arcanjo. The differences highlight the need to adjust the concentration ranges of nutrients in leaf analysis, through regional trials, taking into account the rootstock and the region under study.

Epidemiologia e quadro clínico do botulismo epizoótico dos bovinos no Estado de São Paulo

In order to investigate epidemiological and clinical aspects of beef cattle mortalities caused by botulism, a syndrome popularly known as doença da vaca caída, studies were carried out in 32 naturally affected 4 to 9 year old cows, 27 belonging to the Nellore breed and 5 to crossbred Nellore, all from 27 farms located in municipalities near Botucatu, State of São Paulo. The epidemiological and clinical features were based, respectively, on the farm and herd managements, and on the general physical examination of the cows. Mouse bioassay and complement microfixation tests were performed to detect the presence of botulinum toxins in liver samples. The results showed that the disease occurs in beef cattle of range breeding systems, reared under inadequate mineral nutrition and deficient health management. Pregnant and milking cows represented the group at risk, and the incidence was higher during the rainy season (December to March), with morbidity and mortality rates of 3,2 ± 3,6%. Clinical examination revealed cows with no alterations of vital signs, behavior, visual and auditory acuities and skin sensation; but revealed ruminal hypomotility, anorexia, dehydration, flaccid para or tetraparesis with permanent recumbency, and a paretic or paralytic tongue. The diagnosis of botulism, involving type C and D toxins, was consistent with the epidemiological and clinical findings.

Growth of Dendrobium nobile Lindl. as related with nutrient concentration in the growing media

Dendrobium nobile orchids were grown for three years in different substrates (tree fern fiber, blocks of pressed coconut bark, bark of Eucalyptus grandis, mixtures with coconut bark blocks and eucalyptus bark and mixtures with the latter materials and charcoal. Plant growth increased with higher concentrations of S (up to 1.6 g/kg), Cu (up to 46 mg/kg) and Zn (up to 147 mg/kg), and decreased with higher concentrations of Ca (up to 13.2 g/kg), Mg (up to 6.6 g/kg) and B (up to 19 mg/kg). High Mo (up to 5.3 mg/kg) caused a more intense loss of leaves after planting. Relations between nutrient concentrations also affected plant growth. With exception of eucalyptus bark, all growing media under study were suitable for plant growth.

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.

Produção de composto orgânico a partir de residuos de plantas medicinais

Extraction of active principles from medicinal plants generates wastes usually discharged. This process does not extract minerals from plant tissues, which may be considered of great value in organic composting. Wastes of 81 medicinal plant species processed at Centroflora/Anidro industry were analyzed for macro and micronutrients, and according to the results, three different ways to elaborate the compost were proposed: a) wastes of medicinal plants with high content of a specific mineral, aiming to fertilize soils where would be cultivated species that need high quantities of that mineral; b) wastes with mineral contents in order to support specific failures on mineral content of a soil; c) wastes of the eleven richest species in each nutrient that should elevate all mineral contents in soil.

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.

Relative bioavailability of zinc in supplemental inorganic and organic sources for Nile tilapia Oreochromis niloticus fingerlings

A 90-day feeding experiment was conducted with sex reversed Nile tilapia (Oreochromis niloticus) fingerlings fed purified or practical diets supplemented with different zinc sources to evaluate fish growth performance and zinc and iron retention in fish bones, fillets, liver, skin and eyes. The relative bioavailability value (RBV) of zinc in the supplemental sources tested was also calculated. Fish were fed with isonitrogenous and isoenergetic purified or practical diets supplemented with 150 mg Zn kg -1, as zinc sulphate monohydrate (ZnSO 4), zinc oxide (ZnO) or zinc amino acid complex (Zn-AA). The feeding trial was conducted in 30, 50 L aquaria where four 0.66 ± 0.01 g (mean ± SD) fingerlings were initially stocked. No significant differences were observed for any growth performance variables (P > 0.05). In practical diets, only ZnSO 4 and ZnO presented bone zinc retention similar to that for the standard zinc source. Zinc concentration in the bone of fish fed practical diet supplemented with Zn-AA (171 ± 3.62 μg g -1) was significantly lower than that verified for the practical diets supplemented with the standard zinc source (200 ± 17.7 μg g -1) or with ZnSO 4 (204 ± 19.9 μg g -1). Assuming the concentration of zinc in bones as the response criterion, the supplemental zinc RBV from ZnSO 4 (105%) was higher than the RBV for Zn-AA (95.1%) or ZnO (94.9%). Iron concentration in the bones of animals fed the non-zinc-supplemented purified diet was significantly higher than that observed for purified diet supplemented with Zn-AA (P < 0,05). The results of the present work allowed us to conclude that ZnSO 4 in relation to ZnO or Zn-AA was the supplemental zinc source with higher zinc bioavailability to Nile tilapia. © 2005 Blackwell Publishing Ltd.

Teores de nutrientes na folha e nos grãos de aveia-preta em função da adubação com fósforo e potássio

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Enraizamento de plantas cultivadas in vitro

The adventitious rooting process of in vitro cultured plantlets is a technique that has been employed for the vegetative propagation of a significant number of native and exotic species. Many factors are associated with the rooting stage influencing positive and/or negatively the establishment of micropropagation protocols. The objective of this work was a literature review of the main inherent factors concerning in vitro rooting process including the correlation among others the endogenous and exogenous auxins levels, juvenility, genotype, mineral nutrition, culture medium conditions, addition of growth regulators and other substances as phenolic compounds and active coal besides growth environmental conditions of in vitro cultures. Although the complete elucidation of all processes involved with rooting of in vitro cultured plants has not been achieved so far, a comprehensive study of the main factors that interfere on rooting is fundamental for the establishment of new researches that might contribute for the rooting of economically important plants.

Efecto de la fertirrigación con n y k en el crecimiento de la palma de coco enano Verde de jiqui

The coconut palm crop has increased with the use of the fertigation technique in Brazil in the last years. The objective of this work was to evaluate the influence of N and K rates via fertigation, on vegetative growth of three year old palms, cultivated in the littoral region of the Ceará State, Brazil, with tropical rainy climate. The study was conducted in a sandy soil using the variety of green dwarfed Jiqui coconut palm. The experimental design was a randomized complete block, with 10 treatments, including five nitrogen and five of potassium rates, according to the model of the experimental matrix Plan Puebla III. The nitrogen and potassiun applications via fertigation influenced significantly the plant height, stem perimeter, and the number of leaves and folioles. © 2009 Universidad Centroccidental Lisandro Alvarado (UCLA).