Presubmergence and green manure affect the transformations of nitrogen-15-labeled urea under lowland soil conditions

The effect of presubmergence and green manuring on various processes involved in [N-15]-urea transformations were studied in a growth chamber after [N-15]-urea application to floodwater. Presubmergence for 14 days increased urea hydrolysis rates and floodwater pH, resulting in higher NH3 volatilization as compared to without presubmergence. Presubmergence also increased nitrification and subsequent denitrification but lower N assimilation by floodwater algae caused higher gaseous losses. Addition of green manure maintained higher NH4+-N concentration in floodwater mainly because of lower nitrification rates but resulted in highest NH3 volatilization losses. Although green manure did not affect the KCl extractable NH4+-N from applied fertilizer, it maintained higher NH4+-N content due to its decomposition and increased mineralization of organic N. After 32 days about 36.9% (T-1), 23.9% (T-2), and 36.4% (T-3) of the applied urea N was incorporated in the pool of soil organic N in treatments. It was evident that the presubmergence has effected the recovery of applied urea N.

Effects of triazole and strobilurin fungicide programmes, with and without late-season nitrogen fertiliser, on the baking quality of Malacca winter wheat

Field experiments were conducted over 3 years to study the effect of applying triazole and strobilurin fungicides on the bread-making quality of Malacca winter wheat. Averaged over all years the application of a fungicide programme increased yields, particularly when strobilurin fungicides were applied. Reductions in protein concentration, sulphur concentration, Hageberg failing number and loaf volumes also occurred as the amount of fungicide applied increased. However, there were no deleterious effects of fungicide application on sodium dodecyl sulphate (SDS) sedimentation volumes, N:S ratios or dough theology. Effects of fungicide application on bread-making quality were not product specific. Therefore, it appears that new mechanisms to explain strobilurin effects on bread-making quality do not need to be invoked. Where reductions in protein concentration did occur they could be compensated for by a late-season application of nitrogen either as granular ammonium nitrate at flag leaf emergence or foliar urea at anthesis. These applications, however, sometimes increased the N:S ratio of the extracted flour and failed to improve loaf volume. Multiple regression analysis revealed that main effects of year, flour protein concentration and N:S ratio could explain 93% of the variance in loaf volume caused by season, fungicide and nitrogen treatments. However, an equally good fit was achieved by just including sulphur concentration with year. (C) 2004 Elsevier Ltd. All rights reserved.

Effects of triazole and strobilurin fungicide programmes, with and without late-season nitrogen fertiliser, on the baking quality of Malacca winter wheat

Field experiments were conducted over 3 years to study the effect of applying triazole and strobilurin fungicides on the bread-making quality of Malacca winter wheat. Averaged over all years the application of a fungicide programme increased yields, particularly when strobilurin fungicides were applied. Reductions in protein concentration, sulphur concentration, Hageberg failing number and loaf volumes also occurred as the amount of fungicide applied increased. However, there were no deleterious effects of fungicide application on sodium dodecyl sulphate (SDS) sedimentation volumes, N:S ratios or dough theology. Effects of fungicide application on bread-making quality were not product specific. Therefore, it appears that new mechanisms to explain strobilurin effects on bread-making quality do not need to be invoked. Where reductions in protein concentration did occur they could be compensated for by a late-season application of nitrogen either as granular ammonium nitrate at flag leaf emergence or foliar urea at anthesis. These applications, however, sometimes increased the N:S ratio of the extracted flour and failed to improve loaf volume. Multiple regression analysis revealed that main effects of year, flour protein concentration and N:S ratio could explain 93% of the variance in loaf volume caused by season, fungicide and nitrogen treatments. However, an equally good fit was achieved by just including sulphur concentration with year. (C) 2004 Elsevier Ltd. All rights reserved.

Effects of the Allosteric Antagonist 1-(4-Chlorophenyl)-3-[3-(6-pyrrolidin-1-ylpyridin-2-yl)phenyl]urea (PSNCBAM-1) on CB1 Receptor Modulation in the Cerebellum

PSNCBAM-1 has recently been described as a cannabinoid CB1 receptor allosteric antagonist associated with hypophagic effects in vivo; however, PSNCBAM-1 effects on CB1 ligand-mediated modulation of neuronal excitability remain unknown. Here, we investigate PSNCBAM-1 actions on CB1 receptor-stimulated [35S]GTPγS binding in cerebellar membranes and on CB1 ligand modulation of presynaptic CB1 receptors at inhibitory interneurone-Purkinje cell (IN-PC) synapses in the cerebellum using whole-cell electrophysiology. PSNCBAM-1 caused non-competitive antagonism in [35S]GTPγS binding studies, with higher potency against the CB receptor agonist CP55940 than for WIN55,212-2 (WIN55). In electrophysiological studies, WIN55 and CP55940 reduced miniature inhibitory postsynaptic currents (mIPSCs) frequency, but not amplitude. PSNCBAM-1 application alone had no effect on mIPSCs; however, PSNCBAM-1 pre-treatment revealed agonist-dependent functional antagonism, abolishing CP55940-induced reductions in mIPSC frequency, but having no clear effect on WIN55 actions. The CB1 antagonist/inverse agonist AM251 increased mIPSC frequency beyond control, this effect was reversed by PSNCBAM-1. PSNCBAM-1 pre-treatment also attenuated AM251 effects. Thus, PSNCBAM-1 reduced CB1 receptor ligand functional efficacy in the cerebellum. The differential effect of PSNCBAM-1 on CP55940 versus WIN55 actions in [35S]GTPγS binding and electrophysiological studies and the attenuation of AM251 effects are consistent with the ligand-dependency associated with allosteric modulation. These data provide the first description of functional PSNCBAM-1 allosteric antagonist effects on neuronal excitability in the mammalian CNS. PSNCBAM-1 allosteric antagonism may provide viable therapeutic alternatives to orthosteric CB1 antagonists/inverse agonists in the treatment of CNS disease.

Bio-fortification of potato tubers using foliar zinc-fertiliser

Worldwide, many people are zinc (Zn)-deficient. Dietary Zn intake can be increased by producing crops with higher concentrations of Zn in their edible portions. This can be achieved by applying Zn-fertilisers to varieties with an increased ability to acquire Zn and to accumulate Zn in their edible portions. Potato (Solanum tuberosum L.) is an important food crop and is, therefore, a target for bio-fortification with Zn. Field trials incorporating a core collection of 23 potato genotypes, performed over 4 years (2006 – 2009), indicated significant genotypic effects on tuber Zn concentration and suggested that tuber Zn concentration was influenced by environmental effects, but also found that genotype environment (G E) interactions were not significant. Tuber Zn concentrations averaged 10.8 mg kg–1 dry matter (DM), and the ratio between the lowest and the highest varietal tuber Zn-concentration averaged 1.76. Tuber Zn concentrations could be increased by foliar Zn-fertilisation. Tuber yields of ‘Maris Piper’ were unaffected by foliar applications of < 1.08 g Zn plant–1. The relationship between tuber Zn concentration and foliar Zn application followed a saturation curve, reaching a maximum at approx. 30 mg Zn kg–1 DM at a foliar Zn application rate of 1.08 g plant–1. Despite a 40-fold increase in shoot Zn concentration compared to the unfertilised controls following foliar Zn fertilisation with 2.16 g Zn plant–1, only a doubling in tuber Zn concentration was observed. This suggests that the biofortification of tubers with Zn was restricted by the limited mobility of Zn in the phloem. A significant positive linear relationship between tuber Zn concentration and tuber N concentration supported the hypothesis of co-transport of Zn and N-compounds in the phloem.

Nitrogen dynamics under Lolium perenne after a single application of different sewage sludge types from the same treatment stream

Three sludge types from the same treatment stream (undigested liquid, anaerobically digested liquid and dewatered, anaerobically digested cake) were used in a field based tub study. Amendments (4, 8, and 16 Mg dry solid (ds)ha(-1)) were incorporated into the upper 15 cm of a sandy loam soil prior to sowing with rye-grass (Lolium perenne L.). Nitrogen transformations in the soil were determined for the 80 d period following incorporation. Nitrogen uptake and crop yield were measured in the cut sward 35 and 70 d after sowing. The study showed that application of sewage sludge at rates as low as 4 Mgha(-1) can have a nutritional benefit to rye-grass over the two harvests. Differences in N transformation, and hence crop nutritional benefit, between sludge types were evident throughout the experiment. In particular, the dewatering process changed the mineral N characteristics of the anaerobically digested sludge, which, when not dewatered, outperformed the other sludges in terms of yield and mineralisation rate at both harvests. The dewatered sludge produced the lowest yield of rye-grass. The undigested liquid sludge had the lowest foliar N and soil NO(3)-N concentrations, possibly immobilised as the large oxidisable C component of this sludge was metabolised by the microbial biomass. Correlation data support the concept of preferential uptake of NH(4)-N over NO(3)-N in Lolium perenne. Results are discussed in the context of managing sludge type and application for a plant nutrient source and NO(3)-N release.

Effect of urea and glycine fuels on the combustion reaction synthesis of Mn-Zn ferrites: Evaluation of morphology and magnetic properties

The goal of this study is to evaluate the influence of the urea and glycine fuels on the synthesis of Mn-Zn ferrite by combustion reaction The morphology and magnetic properties of the resulting powders were investigated. The powders were characterized by X-ray diffraction (XRD), nitrogen adsorption (BET), scanning and transmission electron microscopy (SEM and TEM), and magnetic measurement of M x H curves. The X-lay diffraction patterns indicated that the samples containing urea resulted in the formation of crystalline powders and the presence of hematite as a secondary phase The samples containing glycine presented only the formation of crystalline and monophases (Mn,Zn)Fe(2)O(4). The average crystallite size was 18 and 35 nm and saturation magnetization was 3.6 and 75 emu/g, respectively, for the samples containing urea and glycine. The samples synthesized with glycine fuel showed better magnetic properties for application as soft magnetic devices. (C) 2009 Elsevier B.V All rights reserved

Crescimento inicial e morfologia foliar em plantas de Enterolobium contortisiliquum (Vell.) Morong. E Erythrina velutina Mart. ex Benth, sob estresse hídrico

The Caatinga is the predominant vegetation type in semi-arid region of Brazil, where many inhabitants depend on hunting and gathering for survival, obtaining resources for: food and feed, folk medicine, timber production, etc. It‟s the dry ecosystem with highest population density in the world. The early stages of development are the most critical during the life cycle of a flowering plant and they‟re primordial to its establishment in environments exposed to water stress. Information about adjustments to the growth of the species, correlated with their studies of distribution in Seridó oriental potiguar, are an important ecological and economic standpoint, because they provide subsidies for the development of cultivation techniques, to programs of sustainable use and recovery of degraded areas. This thesis aimed to study the initial growth and foliar morphology in plants like Enterolobium contortisiliquum (Vell.) Morong. (tamboril) and Erythrina velutina Mart. ex Benth (mulungu), species of occurrence in the Caatinga, under water stress. After sowing and emergency, the seedlings were exposed to three water regimes: 450 (control), 225 (moderate stress) and 112.5 (severe stress) mm of water slide for 40 days. Seeding occurred in bags of 5 kg and after the establishment of seedlings thinning was carried out leaving a plantlet per bag. At the beginning the waterings occurred daily with distilled water, passing to be on alternate days after thinning. Twenty and forty days after the thinning seedlings collections were held to be done analysis of growth and biomass partition. When compared to the control group, the treatments with water stress showed reduction in the growth of the aerial part, growth of the greater root, number of leaves and leaflets, dry leaf area and total phytomass in both species, but in general, this effect was most marked for E. velutina. Regarding the partition of biomass, there were few changes throughout the experiment. Morphological changes in the leaves as a function of stress were not significant, however, there was a trend, in both species, to produce narrower leaves, that facilitate heat loss to the environment. It has not been possible to establish a positive relationship between inhibition of growth and distribution of species, whereas E. velutina is a species of most common occurrence in Seridó oriental potiguar. In this way, other aspects should be taken into account when studying the adaptation of species the dry environments, such as salinity, presence of heavy metals, wind speed, etc

Determinantes locais da decomposição foliar e de raízes finais em um ecossistema semiárido do nordeste brasileiro

The decomposition process exercises an extensive control over the carbon cycle, affecting its availability and nutrient cycling in terrestrial ecosystems. The understanding of leaf decomposition patterns above the soil and fine roots decomposition below the soil is necessary and essential to identify and quantify more accurately the flow of energy and matter in forest systems. There is still a lack of studies and a large gap in the knowledge about what environmental variables act as local determinants over decomposition drivers. The knowledge about the decomposition process is still immature for Brazilian semiarid region. The aim of this study was to analyze the decomposition process (on leaves and fine roots) of a mixture of three native species for 12 months in a semiarid ecosystem in Northeast Brazil. We also examined whether the rate of decomposition can be explained by local environmental factors, specifically plant species richness, plant density and biomass, soil macro-arthropods species richness and abundance, amount of litterfall and fine root stock. Thirty sampling points were randomly distributed within an area of 2000 m x 500 m. To determine the decomposition rate, the litterbag technique was used and the data analysis were made with multiple regressions. There was a high degradation of dead organic matter along the experiment. Above ground plant biomass was the only environmental local factor significantly related to leaf decomposition. The density of vegetation and litter production were positively and negatively related to decay rates of fine roots, respectively. The results suggest that Caatinga spatial heterogeneity may exert strong influences over the decomposition process, taking into account the action of environmental factors related to organic matter exposure of and the consequent action of solar radiation as the decomposition process main controller in this region

Compatibilidade entre acaricidas e fertilizantes foliares em função de diferentes águas no controle do ácaro da leprose dos citros Brevipalpus phoenicis

A adição de fertilizantes foliares à calda acaricida é frequentemente empregada na citricultura com o intuito de reduzir os custos das aplicações. Todavia, as implicações desta prática, na maioria dos casos, são desconhecidas. O objetivo do trabalho foi avaliar o efeito de caldas acaricidas em mistura com fertilizantes foliares e preparadas com diferentes águas no controle do ácaro B. phoenicis. Foram realizados dois experimentos em laboratório, nos anos de 2009 e 2010, utilizando-se de frutos de laranja para conter ácaros Brevipalpus phoenicis. Um dos experimentos constou de três bioensaios, nos quais se procurou verificar o efeito das misturas entre fertilizantes foliares e os acaricidas cyhexatin, propargite e acrinatrhrin sobre B. phoenicis. No outro experimento, além de verificar o efeito das misturas de fertilizantes com os acaricidas propargite e acrinatrhrin, buscou-se também avaliar o efeito de águas coletadas em diferentes fontes utilizadas no preparo das caldas sobre B. phoenicis. Os resultados evidenciaram que a aplicação dos fertilizantes foliares cloreto de zinco, cloreto de manganês, ureia e a mistura de fosfito de potássio + ureia + cloreto de zinco não afetaram a ação dos acaricidas cyhexatin, propargite e acrinathrin sobre o controle de B. phoenicis. As misturas dos cloretos de zinco e de manganês com o sulfato de magnésio e a adição de fosfito de potássio diminuíram a eficiência dos acaricidas propargite e acrinathrin, não devendo, a princípio, ser adicionadas numa mesma aplicação. Águas provenientes dos municípios paulistas de Itápolis, Pirangi e Pirassununga interferiram na ação dos acaricidas propargite e acrinathin sobre B. phoenicis, sendo que a água coletada em Itápolis apresentou resultados superiores em termos de eficiência. Verificaram-se alterações dos valores de pH e da condutividade elétrica após a adição de alguns dos fertilizantes à calda acaricida.

Liming and Manganese Foliar Levels in Orange

Citrus cultures have a fundamental importance to the Brazilian economy; certain aspects such as plant nutrition, yield, and fruit quality are vital for the citrus industry sustainability. The present study evaluated the nutritional status of manganese in adult Pear orange trees using different lime rates topically applied to the soil. The direct evaluation of lime rates effects on leaf manganese (Mn) levels revealed a decrease of the nutrient correlated to its increased, as well as passage of time between application and measurement. Foliar sampling 30 months after surface lime application evidenced a high correlation of foliar manganese levels with soil base saturation of 10-20 cm. Leaf manganese levels which showed a great probability of high productivity were between 33 and 70 mg kg-1.

Calagem e diagnose foliar em sorgo sacarino (Sorghum bicolor L. moench)

Os efeitos da aplicação de cinco níveis de calcário dolomítico (0 - 1,25 - 2,50-5,00 e 10,00 t/ha) foram estudados em um Latossol Vermelho Escuro textura média. A calagem aumentou a produção de colmos de sorgo sacarino, sendo que as produções mais elevadas foram obtidas quando a soma de cálcio e magnésio, saturação em bases e valor pH do solo eram, respectivamente, 2,93 meq/100 cm³, 59% e 5,71. Foram observados desequilíbrios na nutrição potássica com a aplicação de 10 t/ha de calcário dolomítico. Os níveis críticos de Mg nas folhas + 4e + 3, coletadas, respectivamente, aos 45e 83 dias, foram 0,19 e 0,31% A qualidade do caldo não foi alterada significativamente pelas doses de calcário dolomítico empregadas.

Impacts of limestone and nitrogen top dressing application on the potassium content in the soil profile and marandu-grass leaf concentration

Objetivou-se avaliar os efeitos de nitrogênio (0, 100, 200, 300 e 400 kg/ha.ano), com ou sem aplicação de calcário dolomítico em cobertura, sobre o teor de potássio (K) do solo nas profundidades de 0 a 5; 5 a 10; e 10 a 20 cm e a concentração de potássio na planta. O experimento foi realizado em Latossolo Vermelho distroférrico de relevo suavemente ondulado, disposto em esquema fatorial 5 × 2, em blocos casualizados, com quatro repetições. A adubação nitrogenada promoveu aumento linear na concentração de potássio na planta e no teor desse mineral na camada de 0 a 5 cm do solo. Ocorreu efeito de inibição competitiva entre a absorção de potássio e cálcio e entre potássio e magnésio. Embora uma fração significativa de potássio retorne à camada superficial do solo pelo resíduo de forragem, em decorrência da maior produção de massa, o aumento da concentração de potássio na planta nas mais altas doses de nitrogênio comprova a importância do suprimento de potássio para a planta, por intensificar a massa de forragem.

Cotton root and shoot growth as affected by application of mepiquat chloride to cotton seeds

Estudou-se o efeito do tratamento de sementes de algodão com cloreto de mepiquat sobre o crescimento inicial de raízes e parte aérea. O experimento, realizado em casa de vegetação, utilizou vasos de PVC adaptados com uma parede frontal de vidro e os tratamentos foram constituídos por cinco doses do cloreto de mepiquat (CM) do ingrediente ativo (i.a.): 0, 3, 6, 9 e 12 g kg-1 de sementes, pulverizado sobre as sementes, e a cultivar FM 993. Massa de matéria seca da parte aérea (folhas, pecíolos e haste), massa de matéria seca da raiz, área foliar, relação parte aérea:raiz, relação área foliar:crescimento radicular, o comprimento da parte aérea foram avaliados aos 21 dias após a semeadura. Crescimento radicular foi avaliado a cada três dias até os 18 dias. O CM aplicado às sementes do algodão promove redução da altura da planta e da área foliar, sem, contudo, afetar produção de massa de matéria seca da parte aérea e raiz, relação parte aérea:raiz, relação área foliar:crescimento radicular e comprimento total de raízes do algodoeiro. Assim, no presente experimento não foi observado efeito negativo do CM aplicado às sementes do algodoeiro na absorção de água pela planta.