12 research outputs found

    Efeito da concentração de nitrogĂȘnio na solução nutritiva e do nĂșmero de frutos por planta sobre a produção do meloeiro Effect of nitrogen concentration in nutrient solution and number of fruits per plant on yield of melon

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    O trabalho foi conduzido em casa de vegetação, na UNESP em Jaboticabal (SP), de junho a novembro de 2001, com o objetivo de avaliar a produção do melĂŁo (Cucumis melo var. reticulatus), hĂ­brido BĂŽnus nÂș2, cultivado em sistema hidropĂŽnico NFT, em função da concentração de nitrogĂȘnio na solução nutritiva (80, 140, 200 e 300 mg L-1) e nĂșmero de frutos por planta (2, 3, 4 e livre). O delineamento experimental utilizado foi o de blocos ao acaso, em parcelas subdivididas, com seis repetiçÔes. Aos 80 dias apĂłs o transplantio, foram observados 2, 3, 4 e 5,1 frutos por planta e, posteriormente na colheita, 2, 2,9, 3,0 e 3,4 frutos por planta, respectivamente para os tratamentos com 2, 3, 4 e fixação livre, sendo esta redução atribuĂ­da ao abortamento de frutos. Houve redução no peso mĂ©dio do 1Âș, 2Âș e 3Âș fruto colhido, com o aumento da concentração de nitrogĂȘnio. Plantas com o menor nĂșmero de frutos, apresentaram maior peso mĂ©dio dos mesmos, porĂ©m com menor produção por planta. A maior produção (2.474 g/planta) foi obtida com 80 mg L-1 de nitrogĂȘnio na solução nutritiva.<br>The effects of different nitrogen concentrations (80; 140; 200 and 300 mg L-1) and fruit number per plant (2; 3; 4 and free setting), were investigated on net melon production (Cucumis melo var. reticulatus, Bonus nÂș 2 hybrid). The experiment was carried out in Jaboticabal, SĂŁo Paulo State, Brazil, in NFT hydroponic system, from June to November, 2001. The experimental design was of randomized split plots, replicated six times. At 80 days after seedling transplant 2; 3; 4 and 5.1 fruits per plant were found. However, at harvest there were 2; 2.9; 3.0 and 3.4 fruits per plant, relative to 2; 3; 4 and free setting per plant treatment. This observed fruit reduction was attributed to fruit abortion. With the increase of nitrogen concentrations a reduction in first, second and third fruit weight was found. Plants with fewer fruits, produced higher average fruit weight and lower yield per plant. The highest yield per plant (2,474 g/plant) was obtained with 80 mg L-1 of nitrogen

    Épocas de plantio e doses de nitrogĂȘnio e potĂĄssio na produtividade e armazenamento da cebola Nitrogen and potassium levels on the onion yield and storage with different planting times

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    O objetivo deste trabalho foi avaliar o efeito de Ă©pocas de plantio e doses de nitrogĂȘnio e potĂĄssio sobre a produtividade e armazenamento de cebola, cultivar Texas Grano 502 PRR. Foram conduzidos dois experimentos de março a novembro de 2001, e de agosto de 2001 a março de 2002. O delineamento experimental foi de blocos ao acaso, em parcelas subdivididas com fatorial 4x3. Nas parcelas ficaram as Ă©pocas de plantio (março e agosto) e nas subparcelas o fatorial compreendendo quatro doses de N (0, 60, 120 e 180 kg ha-1) e trĂȘs doses de K2O (0, 90 e 180 kg ha-1), com trĂȘs repetiçÔes. O plantio de março apresentou maior produtividade comercial (66,5 Mg ha-1) comparativamente ao de agosto (41,4 Mg ha-1). Na ausĂȘncia da adubação potĂĄssica e na dose de 90 kg ha-1 de K2O, verificaram-se incrementos lineares na produtividade comercial de acordo com a adubação nitrogenada, enquanto na dose 180 kg ha-1 de K2O, a adubação nitrogenada apresentou comportamento quadrĂĄtico, com ponto de mĂ­nima produtividade na dose de 23,5 kg ha-1 de N. Quanto Ă  produtividade nĂŁo-comercial, o plantio de março alcançou 6,0 Mg ha-1, enquanto o de agosto alcançou 5,4 Mg ha-1. Observaram-se efeitos significativos de N e K e da interação para perda de massa de bulbos aos 40 e 80 dias apĂłs cura.<br>The objective of this work was to evaluate the effect of different planting times and nitrogen and potassium levels on onion yield and postharvest storage, cultivar Texas Grano 502 PRR. Two trials were carried out from March to November 2001 and from August 2001 to March 2002, in Brazilian Northeast. A randomized complete block design with split-plot in a 4x3 factorial scheme was used. The plots consisted of planting dates (March and August) and the subplots of the factorial involving four levels of nitrogen (0, 60, 120 and 180 kg ha-1) and three levels of potassium (0, 90 and 180 kg ha-1 K2O) with three replications. The March planting showed higher commercial yield (66.5 Mg ha-1) than August plating (41.4 Mg ha-1). In the absence of the potassium fertilization and at the level of 90 kg ha-1 of K2O, linear increments were observed in the commercial yield according to nitrogen fertilization, while at 180 kg ha-1 of K2O, the nitrogen fertilization showed quadratic behavior, with point of minimum yield at 23.5 kg ha-1. Regarding non-commercial yield (culls), the March planting obtained 6.0 Mg ha-1 and August 5.4 Mg ha-1. Significant effects of N, K and of the interaction were observed for bulb mass loss at 40 and 80 days after cure

    Immune-escape mutations and stop-codons in HBsAg develop in a large proportion of patients with chronic HBV infection exposed to anti-HBV drugs in Europe

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    Abstract Background HBsAg immune-escape mutations can favor HBV-transmission also in vaccinated individuals, promote immunosuppression-driven HBV-reactivation, and increase fitness of drug-resistant strains. Stop-codons can enhance HBV oncogenic-properties. Furthermore, as a consequence of the overlapping structure of HBV genome, some immune-escape mutations or stop-codons in HBsAg can derive from drug-resistance mutations in RT. This study is aimed at gaining insight in prevalence and characteristics of immune-associated escape mutations, and stop-codons in HBsAg in chronically HBV-infected patients experiencing nucleos(t)ide analogues (NA) in Europe. Methods This study analyzed 828 chronically HBV-infected European patients exposed to ≄ 1 NA, with detectable HBV-DNA and with an available HBsAg-sequence. The immune-associated escape mutations and the NA-induced immune-escape mutations sI195M, sI196S, and sE164D (resulting from drug-resistance mutation rtM204 V, rtM204I, and rtV173L) were retrieved from literature and examined. Mutations were defined as an aminoacid substitution with respect to a genotype A or D reference sequence. Results At least one immune-associated escape mutation was detected in 22.1% of patients with rising temporal-trend. By multivariable-analysis, genotype-D correlated with higher selection of ≄ 1 immune-associated escape mutation (OR[95%CI]:2.20[1.32–3.67], P = 0.002). In genotype-D, the presence of ≄ 1 immune-associated escape mutations was significantly higher in drug-exposed patients with drug-resistant strains than with wild-type virus (29.5% vs 20.3% P = 0.012). Result confirmed by analysing drug-naĂŻve patients (29.5% vs 21.2%, P = 0.032). Strong correlation was observed between sP120T and rtM204I/V (P

    Immune-escape mutations and stop-codons in HBsAg develop in a large proportion of patients with chronic HBV infection exposed to anti-HBV drugs in Europe

    No full text
    Abstract Background HBsAg immune-escape mutations can favor HBV-transmission also in vaccinated individuals, promote immunosuppression-driven HBV-reactivation, and increase fitness of drug-resistant strains. Stop-codons can enhance HBV oncogenic-properties. Furthermore, as a consequence of the overlapping structure of HBV genome, some immune-escape mutations or stop-codons in HBsAg can derive from drug-resistance mutations in RT. This study is aimed at gaining insight in prevalence and characteristics of immune-associated escape mutations, and stop-codons in HBsAg in chronically HBV-infected patients experiencing nucleos(t)ide analogues (NA) in Europe. Methods This study analyzed 828 chronically HBV-infected European patients exposed to ≄ 1 NA, with detectable HBV-DNA and with an available HBsAg-sequence. The immune-associated escape mutations and the NA-induced immune-escape mutations sI195M, sI196S, and sE164D (resulting from drug-resistance mutation rtM204 V, rtM204I, and rtV173L) were retrieved from literature and examined. Mutations were defined as an aminoacid substitution with respect to a genotype A or D reference sequence. Results At least one immune-associated escape mutation was detected in 22.1% of patients with rising temporal-trend. By multivariable-analysis, genotype-D correlated with higher selection of ≄ 1 immune-associated escape mutation (OR[95%CI]:2.20[1.32–3.67], P = 0.002). In genotype-D, the presence of ≄ 1 immune-associated escape mutations was significantly higher in drug-exposed patients with drug-resistant strains than with wild-type virus (29.5% vs 20.3% P = 0.012). Result confirmed by analysing drug-naĂŻve patients (29.5% vs 21.2%, P = 0.032). Strong correlation was observed between sP120T and rtM204I/V (P
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