No abstract

Nectarine contain relevant amounts of antioxidants, including hydroxycinnamic acids, flavan-3-ols, flavonols, anthocyanins, procyanidins, and carotenoids. The aim of this research was to compare the efficiency of DPPH and FRAP assays to estimate antioxidant activities contents in nectarine minimally processed. Moreover, separation of organic acids, phenolic compounds and carotenoids were done by HPLC. Nectarine fruits ‘R48’ cv. were hand harvested, with 80% of their reddish coloration. The following treatments were applied: Control; 1% citric acid + 1% calcium chloride as anti-browning (AB) agent; 4 KJ m-2 UV-C radiation; 8 KJ m-2 UV-C; 12 KJ m-2 UV-C ; AB +  95 kPa O2 (High O2); AB + 4 KJ m-2 UV-C + High O2; AB + 8 kJ m-2 UV-C + High O2 and AB + 12 KJ m-2 UV-C + High O2. We determined antioxidant activity to DPPH; antioxidant activity to FRAP; total phenols and HPLC-DAD analyses. In general the DPPH showed higher efficiency of antioxidant concentration in comparison with FRAP in minimally processed nectarines. There was clear trend in phenolic content in fresh-cut nectarine the treatment AB + 8 kJ m-2UV-C + High O2. The 22 minimally processed nectarine phenolic compounds were studied and quantified by HPLC, being detected: Hydroxycinnamates, flavonols, and anthocyanins. These results allow to conclude that the most abundant compounds found in this study of fresh-cut nectarine were chlorogenic acid, caffeic acid and ellagic acid with HPLC chromatograms were recorded at 280 nm, quercentin 3-galactoside, quercetin 3- Xyloside at 340nm and Cyanidin 3- glucoside at 510nm.

RESUMO: O sucesso de programas de manejo de plantas espontâneas depende do conhecimento das características biológicas e ecológicas das mesmas. Desta forma esta pesquisa tem como objetivo caracterizar a composição florística e fitossociologia em populações de plantas espontâneas em ecossistemas de pastagens cultivadas a mais de dez anos, no município de Ipixuna do Pará, Nordeste Paraense, considerando-se três espécies de gramíneas (Brachiaria (Syn. Urochloa) humidicola, Brachiaria (Syn. Urochloa) brizantha cv. Marandu e Brachiaria (Syn. Urochloa) decumbens cv. Basilisk). Os estudos foram conduzidos no Município de Ipixuna do Pará, região nordeste paraense. Para este estudo foi aplicado o método do quadrado inventário na sequência fez-se a identificação e contagem das plantas, e posteriormente realizou-se a identificação através de literatura especializada e comparações com herbários virtuais.  O Índices de similaridade de Sörensen (ISS) foi expresso em porcentagem, sendo máximo (100%) quando todas as espécies são comuns às duas áreas e mínimo (0%) quando não há espécies comuns. Constatou-se que a composição florística na pastagem de B. (Syn. Urochloa) humidicola, foram identificados, 10 famílias, 12 gêneros e 12 espécies de plantas espontâneas, em B. (Syn. Urochloa) brizantha cv. Marandu, foram ideficados, 12 famílias, 15 gêneros e 16 espécies, enquanto que no ecossistemas com B. (Syn. Urochloa) decumbens cv. Basilisk, foram encontrados 13 famílias, 24 gêneros e 25 espécies. O maior índice de similaridade foi entre os ecossistemas B. (Syn. Urochloa) humidicola e B. (Syn. Urochloa) brizantha, enquanto que o menor foi entre os ecossistemas B. (Syn. Urochloa) decumbens e B. (Syn. Urochloa) humidicola.PALAVRA-CHAVE:  Comunidade infestante, Ecossistemas, Índice de similaridade.

Approximately 15,000 ha of melon (Cucumis melo L.) are grown in the northeastern section of Brazil, mostly for export to Europe during the winter months. Surveys for melon vine decline diseases were carried out in farms in the municipalities of Mossoró (Rio Grande do Norte) and Quixeré (Ceará) during 2002 and 2003. Symptoms typical of vine decline were observed in several fields and included yellowing of crown leaves just prior to harvest and collapse of many of the vines. Affected plants exhibited necrotic root systems and lacked most of the secondary and tertiary feeder roots. Numerous perithecia were observed on roots which, when examined with a microscope, showed characteristic asci and ascospores of the fungus Monosporascus cannonballus Pollack & Uecker (2). Isolations were made from the crown region and primary and secondary roots of affected plants by excising 4- to 6-mm pieces that were surface sterilized for 30 to 60 s with 1.5% active chlorine solution. Seven tissue pieces from each plant part were placed on potato dextrose agar (PDA) containing 0.5 g liter-1 of streptomycin sulfate. Plates were examined daily for fungal growth for 7 days, and hyphal tips from all colonies were transferred to PDA for subsequent growth and sporulation. M. cannonballus was isolated from 50% of the root sections. All isolates produced only one ascospore per ascus. Pathogenicity of four isolates was confirmed in the greenhouse on the muskmelon cv. Temprano Rochet. Inoculum was produced in a sand-oat hulls (Avena sativa L.) medium (0.5 liter of sand, 46 g of ground oat hulls, and 37.5 ml of distilled water) and incubated at 25°C for 1 month. Colony forming units (CFU) were quantified by serial dilution using 1% hydroxyethyl cellulose. A sterilized mixture of equal portions (vol/vol) of sand and peat moss was used to fill plastic pots (17 cm in diameter), and inoculum was added to produce an inoculum concentration of 20 CFU g-1. Five melon seeds were planted in each pot and after germination, were thinned to one seedling per pot. There were five replicated pots for each treatment with an equal number of uninfested pots. Plants were evaluated for disease 45 days after sowing. Roots were exposed by carefully washing the potting mix away. All isolates of M. cannonballus tested were highly aggressive and caused severe root necrosis compared with the noninoculated control plants. M. cannonballus was reisolated from symptomatic plants, confirming Koch's postulates. Double cropping in the same fields for several years has created serious problems in Brazil, which are related to this soilborne pathogen that also causes root rot and vine decline of watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) worldwide (1). To our knowledge this is the first report of M. cannonballus in Brazil and South America. References: (1) R. D. Martyn and M. E. Miller. Plant Dis. 80:716, 1996. (2) F. G. Pollack and F. A. Uecker. Mycologia 66:346, 1974.

RESUMO: A utilização de cobertura morta tem se mostrado uma alternativa no cultivo de hortaliças uma vez que possibilita a redução da oscilação da temperatura do solo, evaporação de água do mesmo, perda de adubos e corretivos por lixiviação. Desta forma objetivou se avaliar a incidência das plantas espontâneas em cultivo de pimentão sob diferentes coberturas mortas. O experimento foi conduzido na Universidade Federal Rural da Amazônia, campus de Paragominas, na área experimental de Horticultura. O delineamento estatístico utilizado foi em esquema fatorial 3x4, sendo utilizadas três cultivares de pimentão: Ikeda, Rubi Gigante e Quadrado vermelho. As coberturas mortas utilizadas foram: palha de arroz, caroço de açái, resíduo de soja e a testemunha. As quais, foram distribuídas de maneira uniforme nas parcelas, com 5 cm de camada de cada material. Avaliou - se a incidência de plantas daninhas na produção de pimentão, utilizando se o método de levantamento do tipo quadrado inventariado, com o auxílio de moldura de madeira, com área interna de 0,50 m², colocado no centro de cada parcela. A cobertura morta com caroço de açaíapresentou melhor tendência no controle de plantas daninhas  na cv. Rubi Gigante e na cv. Casca Dura Ikeda de pimentão. Enquanto que o resíduo de soja apresentou tendência a ser mais eficiente  no cultivo de pimentão cv. Quadrado Vermelho.PALAVRAS-CHAVE: Cobertura do solo, Hortaliça-fruto, Palha de arroz.

The effect of the enzymatic CaCO3 precipitation on the behaviour of four soils (from a poorly graded sand to a fine and organic soil) is studied in this work. The analysis is based on the results of UCS tests, where the results from the non-stabilised specimens are compared with specimens stabilised with a urease concentration of 8 kU/L and an equimolar solution of urea-CaCl2 of 0.5 mol/L. Additionally, pH and scanning electron microscopy (SEM) tests with energy dispersive X-ray (EDX) analyses are performed to analyse the microstructure and the local chemical composition. The results of the UCS tests show that, in the case of the sandy and silty soils, the process of enzymatic CaCO3 precipitation potentiates the strengthening of the soils while, in the organic soil, a detrimental effect is observed. The SEM tests show the existence of vestiges of calcium in the biostabilised soils studied.

O controle químico não tem apresentado eficiência em determinadas regiões brasileiras, devido ao hábito de lagartas Spodoptera eridania permanecer na região inferior das folhas, dificultando que a molécula química atinja o alvo. Diante disso, o objetivo do trabalho foi verificar a eficiência do produto biológico a base de Bacillus thuringiensis no controle da lagarta Spodoptera eridania. O trabalho foi realizado na fazenda Água Boa localizada no município de Paragominas-PA. O delineamento experimental utilizado foi inteiramente casualizado, com 4 tratamentos e 4 repetições, os tratamentos foram: 1 - Testemunha; 2 -  Xentari + Klorpan  (biológico); 3 - Dimax + Klorpan; 4 - Prêmio + Brutos. Os parâmetros avaliados foram nível de largatas e controle, desfolha, fitotoxicidade, peso de mil grãos, umidade, custo x benefício e produtividade. Os dados foram submetidos à análise de variância (ANOVA) e comparados pelo teste de Tukey, a 5% de probabilidade. O Inseticida biológico à base Bacillus thuringiensis, Xentari + Klorpan proporcionou um maior controle de lagartas Spodoptera eridania, melhor produtividade e rendimentoda soja, no município de Paragominas. Destaca-se que esse inseticida biológico proporcionou benefícios tanto para o produtor, no que se refere à produtividade e lucro, como para o meio ambiente.

The conversion of forest areas to grain cropping has promoted a decrease in soil organic matter stocks in the Amazon. This process is most striking when the conventional cultivation system is used. In order to evaluate the changes in soil carbon and nutrient stocks resulting from the time of adoption of the no tillage system in a dystrophic Yellow Oxisol of the Brazilian Amazon biome, a study was conducted in a grain producing area in the northeastern of Pará, Brazil. The treatments corresponded to the following systems: CT6- conventional tillage system with six years of implementation; No-tillage system with 3 (NT3), 4 (NT4) and 7 (NT7) years of implementation. All systems were always cultivated in corn / soybean rotation. Deformed and non-deformed soil samples were collected on a the 2013 crop year at 0-10, 10-20 and 20-40 cm depths. Stocks of carbon (SC) and phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) were calculated by using the equivalent soil mass methodology. Regardless of depth, the NT showed higher SC values than the CT. The adoption of NT showed a tendency of increasing SC of the soil over time. Such increases were up to 36% of the NT7 compared to the CT6. In NT7, the stocks of K, Ca and Mg were higher in relation to PC6. The EC correlated positively with the stocks of K, Ca and Mg in the areas under NT, regardless of the time of system adoption, up to 40 cm deep, indicating improvements in the soil fertility.