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Carbon-13 Solid State NMR Techniques to Evaluate the Morphology of PP/TiO₂ Composites

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Materials Sciences and Applications 2016年第1期7卷 20-25页

作者： Igor Lopes Soares Maria Inês Bruno Tavares André Luis B. B. e Silva Antonio Gabriel Malagueta Feio Instituto de Macromoléculas Universidade Federal do Rio de Janeiro Rio de Janeiro Brazil Instituto Federal do Mato Grosso IFMT Mato Grosso Brazil CENIMAT/I3N Departamento de Ciência dos Materiais Faculdade de Ciências e Tecnologia Universidade Nova de Lisboa Caparica Portugal

Solid state NMR was successfully used to determine the proton spin-lattice relaxation time in the rotating frame (T1ρH) for systems based on polypropylene (PP) and PP with titanium dioxide (TiO2) organically modified or unmodified incorporated, in order to understand the molecular behavior of these systems. These techniques were employed in the samples organically modified and unmodified TiO2 to investigate the effect of organic modification on the dispersion and distribution of the particles in the PP matrix. The results were analyzed in terms of the effect of the particles organic modified or not according to the intermolecular interaction in the composites. According to the T1ρH values, all composites showed at least two domains: the short values were related to the rigid part, which included the crystalline and amorphous phase constricted in it, while the longer times were attributed to the amorphous region, which had higher molecular mobility compared to the rigid region of the materials. The increase in the relaxation time parameter in the composites compared to the pure PP was associated to the strong interaction between titanium dioxide particles and the polymer chains. This effect was more pronounced for the systems containing organically modified TiO2. According to the results, it could be inferred that intermolecular interaction occurred in the CH2 and CH groups, being more intense with CH2 groups. Finally, the solid state NMR techniques were able to evaluate the molecular dynamics of those systems.

关键词： NMR PP TiO2 Composites

Chemical Screening of <i>Urochloa humidicola</i>: Methods for Characterizing Secondary Metabolites and Allelopathic Activity on Forage Legumes

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American Journal of Plant Sciences 2018年第6期9卷 1260-1278页

作者： R. C. Ribeiro M. G. de Carvalho M. de L. L. de Moraes R. O. P. Rossiello D. R. de Oliveira R. M. Q. de Amorim E. Barbieri Junior Phytochemistry Laboratory (PL) Department of Chemistry Federal Rural University of Rio de Janeiro (UFRRJ) Seropédica-Rio de Janeiro Brazil Instituto Federal de Educacao Ciência and Tecnologia de Mato Grosso (IFMT) Sorriso-MT Brazil Department of Chemistry Federal University of Sao Paulo (Universidade Federal de Sao Paulo-UNIFESP) Diadema-SP Brazil Cultivated Plants Ecophysiology Laboratory Department of Soils Federal Rural University of Rio de Janeiro (UFRRJ) Seropédica-Rio de Janeiro

The aim of this study was to identify the main classes of secondary metabolites present in the root and shoot crude extracts and fractions from the forage grass Urochloa humidicola (Rendle) Morrone & Zuloaga and to evaluate the allelopathic effect of these metabolites on forage legumes for intercropping. Phytochemical prospecting analyses, 1H NMR and capillary electrophoresis were performed on extracts of U. humidicola. Allelopathic activity was evaluated in germination of Stylosanthes, Macrotyloma axillare and Lactuca sativa L. (standard) in the presence of crude extracts, isolated saponins, flavonoids and trans-cinnamic acid. The metabolite classes present in the extracts could be determined by the combined use of the tested analytical techniques, but their use alone was usually not sufficient to chemically characterize the species. Capillary electrophoresis was effective in detecting phenolic compounds. Macrotyloma axillare was tolerant to crude extracts of U. humidicola. Saponins and trans-cinnamic acid, but not the flavonoids, reduced germination of the target plants.

关键词： Phenolic Compounds Legume-Forage Grasses Consortium Capillary Electrophoresis Macrotyloma axillare Stylosanthes spp

Epidemiologic Study of Ramularia areola under Different Soil Covers and Spacings,for Cotton Crops

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American Journal of Plant Sciences 2013年第11期4卷 2049-2059页

作者： Jaqueline Aguilla Pizzato Dejania Vieira Araújo Milson Evaldo Serafim Kelly Lana Araújo Rivanildo Dallacort Thiago Alexandre Santana Gílio Jair Romano Jr Vanderlei Antunes Maciel Programa de Pós-graduacao em Ambiente e Sistemas de Producao Agrícola Universidade do Estado de Mato GrossoTangaráda SerraBrasil Instituto Federal de Educacao Ciência e Tecnologia de Mato Grosso—IFMTCáceresBrasil Laboratório de Melhoramento Genético Vegetal.Universidade do Estado de Mato Grosso CáceresBrasil Programa de Pós-graduacao em Genética e Melhoramento de Plantas Universidade do Estado de Mato GrossoTangaráda SerraBrasil Laboratório de Fitopatologia Universidade do Estado de Mato GrossoTangaráda SerraBrasil

The objective of this work was to evaluate the progress of the areolate mildew of cotton under different soil cover and spacing conditions. The experiment was carried out using randomized blocks and a 2 × 3 factorial design, with two spacings (0.45 m and 0.90 m) and three soil covers (no cover, Pennisetum glaucum and Crotalaria spectabilis) with four replications. The plants were inoculated with R. areola, sixty DAS. A total of 14 evaluations of disease severity were performed. At the lower, middle and upper thirds of plants, a diagram scale with nine levels of severity was used and the resulting data were converted into the AUDPC. Gompertz, logistic, and monomolecular mathematical models were tested in the disease severity curves for each third. Agronomics characteristics were evaluated as well. Significant differences of AUDPC were found for the cotton plants thirds, and the middle third was the highest AUDPC. Significant difference for the lower and upper thirds, whose AUDPC were highest on 0.90 m spacing, was observed too. The disease progress curves of the thirds did not fit the tested models. Significant results to the both covers situations, where the treatments grown on crotalária cover and without cover had highest AUDPC, were evidenced. The treatments with C. spectabilis cover were taller than other treatments. Significant data were observed for the cover crops used and in the treatments grown at 0.90 m spacing, to residual cover and crop yield, respectively.

关键词： Pennisetum glaucum Crotalaria spectabilis Areolate Mildew High-Density Crops and No-Till

Humic Acid-Induced Hairy Root Growth in Basil Ismodulated by Nitric Oxide and Reactive Oxygen Species

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American Journal of Plant Sciences 2017年第12期8卷 3140-3161页

作者： Flávio Couto Cordeiro Claudete Santa-Catarina Vanildo Silveira Roberta Cristiane Ribeiro Sonia Regina de Souza Plant Biochemistry Laboratory (LBP) Department of Chemistry Federal Rural University of Rio de Janeiro (UFRRJ) Seropédica Brazil Cell Biology and Tissue Laboratory (LBCT) Center for Bioscience and Biotechnology (CBB) State University of Norte Fluminense Darcy Ribeiro (UENF) Campos dos Goytacazes Brazil Biotechnology Laboratory (LBT) Center for Bioscience and Biotechnology (CBB) State University of Norte Fluminense Darcy Ribeiro (UENF) Campos dos Goytacazes Brazil Plant Nutrition Laboratory (LNP) Department of Soils Federal Rural University of Rio de Janeiro (UFRRJ) Seropédica Brazil Instituto Federal de Educacao Ciência and Tecnologia of Mato Grosso (IFMT) Sorriso Brazil Plant Biochemistry Laboratory (LBP) Department of Chemistry Federal Rural University of Rio de Janeiro (UFRRJ) Seropédica Brazil

The bioactivity of humic acids (HA) is mainly due to the presence of auxin analogs. In turn, nitric oxide (NO) production in plants affects root growth and may result from endogenous auxin production or the application of synthetic auxin analogs or HA. Nitric oxide signaling may be related to the bioactivity of the HA. Although the auxin, NO, and ROS-mediated activity of HA has been studied, no studies exist on their effects in Ocimum basilicum L., commonly known as basil. A study under controlled in vitro conditions was performed using hairy roots (hairy roots) of basil grown in medium with N-NO3- (0.5 or 5.0 mM) and subjected to treatments with HA (3 mMC·L-1) or sodium nitroprusside (SNP;100 μM), an NO donor, either without or with 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO;200 μM), an NO scavenger. The addition of HA and SNP resulted in significant increases in the root growth, associated with increased NO and reactive oxygen species (ROS) contents. The application of the NO scavenger cPTIO with the SNP and HA decreased the effects of both substances on the root growth and endogenous levels of the NO and ROS. The increased root growth promoted by the NO donor (SNP) and HA was also associated with increased proton pump and catalase activity for both N-NO3- levels tested. The results showed that the effects of HA are dependent on NO and ROS, which act as messengers, inducing root growth.

关键词： H+-ATPases Auxins Humic Acid Ocimum basilicum L. Root Growth