rESUMo -o desconhecimento sobre as características físicas de sementes de espécies florestais dificulta o desenvolvimento de metodologias para a sua avaliação e preservação. A Senna macranthera (Collad.) Irwin et Barn. é uma planta pioneira que pertence à família Leguminosae -Caesalpinioideae, conhecida popularmente como fedegoso e suas sementes possuem dormência tegumentar. Neste estudo foi realizada a caracterização física das sementes desta espécie em relação ao diâmetro médio de Sauter, esfericidade, densidade (real, aparente e bulk), porosidade da partícula, ângulo de repouso dinâmico e o peso de 1000 sementes (3,3 mm; 0,52; 1397,2 kg.m -³; 1371,9 kg.m -³; 884,4 kg.m -³; 1,81%; 10º e 41,05 g, respectivamente). Além disso, as sementes de S. macranthera foram acondicionadas em sacos de plástico e armazenadas em geladeira convencional a 5 ºC durante 280 dias e, periodicamente, foram realizadas análises de germinação e umidade. Para a quebra da dormência, as sementes foram escarificadas quimicamente por imersão em ácido sulfúrico concentrado durante 20 minutos. o teste de germinação indicou que as sementes se mantiveram viáveis durante o período analisado.Termos para indexação: fedegoso, densidade, porosidade, esfericidade, viabilidade PhYSICAL ChArACTErIzATIoN AND GErMINATIoN oF Senna macranthera SEEDS ABSTRACT -Poor knowledge of the physical traits of forest species seeds causes difficulties in developing methodologies for their assessment and preservation. Senna macranthera (Collad.) Irwin et Barn. is a leguminous pioneer plant that belongs to the Caesalpinioideae. It is popularly known as "fedegoso" and its seeds have tegumentary dormancy. In this study, physical characterization of fedegoso seeds was obtained by evaluating the Sauter mean diameter, sphericity, densities (real, apparent and bulk), porosity, dynamic angle of repose and weight of 1000 seeds: 3.3 mm; 0.52; 1397.2 kg.m -³; 1371.9 kg.m -³; 884.4 kg.m -³; 1.81%; 10º and 41.05 g, respectively. S. macranthera seeds were packed in plastic bags and stored in a conventional refrigerator at 5 ºC for 280 days and analyzed periodically for germination and moisture content. The seeds were chemically scarified by immersion in concentrated sulphuric acid for 20 minutes to break dormancy. The germination tests showed that seeds remained viable during storage.
-In order to allow using seeds from three interspecific elephant grass × pearl millet hybrids (Original, Cutting Palavras-chave: equação de viabilidade, Pennisetum purpureum × P. glaucum, seleção recorrente
-An interspecific hybrid resulting from the crossing of elephant grass (Pennisetum purpureum Schumach) x pearl millet (Pennisetum glaucum (L.) R. Brown) has been developed. This hybrid, however, revealed low phenotypic uniformity and low production of pure seeds. Through recurrent selection, two improved populations were obtained (genotypes Corte and Pastoreio). The aim of this study was assessing seed quality of the three hybrids (genotypes Corte, Pastoreio and Paraiso) by tests of: seed purity; seed germination; accelerated aging test, at 42 ºC; 1,000 seeds weight; drying curves; and sorption and desorption isotherms. Recurrent selection altered the seed size and increased initial quality of population for genotype Pastoreio. Drying curves for the three hybrids have shown similar behavior and reached moisture contents of 2.1%, 1.9%, and 1.8%, respectively, after 63 days. The accelerated aging test showed that hybrid Pastoreio was the most vigorous.
For the process of coating in spouted bed, the physical characteristics of the particles to be coated, the formulation of coating suspension and the operating conditions such as the air flow, the pressure of atomization, the flow of suspension, the air temperature and the mass of solids are important parameters that influence the process performance. In the case of seeds, coating can be applied to facilitate handling, transporting and sowing, to protect the seeds against insects and for the conservation of species to environmental preservation. In this work the process of coating of forest seeds of Senna macranthera species in spouted bed was studied and analysis of the physiological quality of covered and in nature seeds during storage were performed. The seeds of this species have tegument dormancy, which hinders the germination due to impermeability of the tegument. The breaking of dormancy in seeds of forest species aims to increase the percentage of seed germination and to uniform the seedling emergence; however, these seeds cannot maintain their viability for long periods and the storage becomes unworkable without dormancy. The first stage of this work involved the physical characterization of the seeds, the definition of operating conditions for the coating process and the development of the formulation of the coating suspension. Then, the seeds underwent to tegument dormancy break by immersion in sulfuric acid before being coated with the polymer suspension developed. The coated seeds and the control (in nature seeds) were stored in conventional refrigerator at a temperature of 5 ºC.The storage period was of 380 days. The results of physical characterization of the seeds in nature were: Sauter diameter of 3.4 mm, sphericity of 0.52, dynamic angle of repose of 10 º, porosity of 1.81 %, weight of thousand seeds of 41.05 g and real, apparent and volumetric densities equal to 1397.2, 1371.9 and 884.4 kg/m³, respectively. For the coated seeds the following values were obtained: Sauter diameter of 3.7 mm, sphericity of 0.69, dynamic angle of repose of 35 º, porosity of 4.30 %, weight of thousand seeds of 50.52 g and real, apparent and volumetric densities equal to 1397.2, 1337.2 and 795.1 kg/m³, respectively. Operating conditions were defined as: suspension flow of 2 ml/min, atomization pressure of 2 psig, inlet air temperature of 70 ºC and load of seeds of 450 g. The formulated suspension was composed of: Eudragit FS 30D ® , triethyl citrate, magnesium stearate, titanium dioxide, talc, pink pigment and water. Scanning electron microscope images of the seeds before and after coating were analyzed.Adsorption isotherms at 25 ºC were determined for the coated and in nature seeds using the dynamic method. The results were adjusted using five models of sorption isotherms: GAB, xi Caurie, Oswin, Peleg and Smith. For the seeds in nature, the best fit was obtained with the model of Peleg (R² = 0.998), whereas for the coated seeds the best fit was obtained with the model of Smith (R² = 0.981). During the storage, three ...
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