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Reguladores vegetais e nutrição mineral na formação de mudas de maracujazeiro-doce
(Universidade Federal de São Carlos, 2018-10-23) Maciel, Glauco Henrique Pinheiro; Baron, Daniel; https://lattes.cnpq.br/2054014705484176; https://lattes.cnpq.br/9469249961994979
Crop plants have been widely used to discuss several physiological interactions between plant growth regulators (PGRs) and mineral nutrition. However, these physiological effects and their potentiality in non-domesticated species (wild species) are far to be elucidated. In this way, we hypothesized that PGRs and mineral element availability interactions guaranteed improvements in plant development under low availability for the establishment of Passiflora alata Curtis (sweet passion fruit) seedlings. We investigated plant growth and ionic accumulation of macro and micronutrients in leaf and root plant tissues of P. alata. As expected, the ionic accumulation of some elements (N, P, S, B, and Cu) increased in response to a higher nutrient solution (ionic strength, IS) availability. The interactions IS x PGR were significant with respect to almost all the plant growth variables, besides the Zn in leaf and N, Zn, and B in roots. By means comparisons, we verified that the plant growth responses and Zn in leaf were more similar between ISs when PGRs had been applied. Moreover, the use of PGR probably favors an adequate nutritional and hormonal balance, since it has guaranteed improvements even under low availability. We can conclude that Passiflora alata Curtis that did not receive these phytoregulators are more variable in terms of nutrient content, and are therefore more susceptible to nutritional deficiencies
Materiais híbridos condutores baseados em grafeno/polímero visando aplicações em monitoramento e remediação de poluentes ambientais
(Universidade Federal de São Carlos, 2018-10-23) Facure, Murilo Henrique Moreira; Corrêa, Daniel Souza; https://lattes.cnpq.br/0461451015026948; https://lattes.cnpq.br/4173216607463824
Graphene is a material composed of a single layer of carbon atoms arranged in rings of six atoms with sp2 hybridization. Graphene displays a high sensitivity towards several molecules. Additionally, graphene presents other interesting features such as high electrical and thermal conductivity, mechanical strength and chemical stability, being considered a material with high potential for several technological applications. Herein, graphene-based and polymer-based materials were produced and used as constituents of sensing units of an electronic tongue in analyzes of organophosphorus pesticides and in pollutants remediation platforms based on the adsorption of methylene blue dye in aqueous solution. Graphene-based materials were obtained by chemical reduction of graphene oxide, which was synthesized using the modified Hummers method. The materials' physicochemical characterization was performed using Fourier transform infrared (FTIR) and UV–vis absorption spectroscopy and the morphology was analyzed using Scanning Transmission Electron Microscopy (STEM) images. The sensing units of the electronic tongue were obtained by using reduced graphene oxide (rGO) and nanocomposites obtained by the combination of the rGO with poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), polypyrrole and gold nanoparticles. The data were treated by Principal Component Analysis (PCA). The system was able to discriminate solutions of OP pesticides at nanomolar concentrations, solutions with the mixture of these pesticides and real samples, presenting a direct relationship between the pesticide concentrations and the values of the principal components in the PCA plots. The materials employed provided sensing units with a high specific surface area and high conductivity, yielding the development of a sensor with high sensitivity. In another work, a nanocomposite made of rGO and poly(methylmethacrylate) nanofibers, produced by the Solution Blow Spinning (SBS) technique, was employed in the adsorption of the methylene blue dye. The dye adsorption kinetics and isotherm follow the pseudo-second-order and the Langmuir models, respectively. The results suggest that the adsorption capabilities of the membrane obtained are due to the synergistic effect of the strong π–π stacking interactions between the dye and the rGO combined with the properties of the electrospun nanofibers, such as high porosity and high-specific surface area per unit mass.