Testes bioquímicos para avaliação do vigor em sementes de Mimosa caesalpiniaefolia Benth

Mimosa caesalpiniaefolia Benth. is a forest species of the Mimosaceae family, recommended for recovery of degraded areas. The evaluation of vigor by biochemical tests have been an important tool in the control of seed quality programs, and the electrical conductivity and potassium leaching the most efficient in the verifying the physiological potential. The objective, therefore, to adjust the methodology of the electrical conductivity test for seeds of M. caesalpiniaefolia, for then compare the efficiency of this test with the potassium in the evaluation of seed vigor of different lots of seeds M. caesalpiniaefolia. To test the adequacy of the electrical conductivity were used different combinations of temperatures , 25 °C and 30 ºC, number of seeds , 25 and 50, periods of imbibition , 4 , 8 , 12 , 16 and 24 hours , and volumes deionized water, 50 mL and 75mL. For potassium leaching test, which was conducted from the results achieved by the methodology of the adequacy of the electrical conductivity test, to compare the efficiency of both tests , in the classification of seeds at different levels of vigor, and the period 4 hours also evaluated because the potassium leaching test can be more efficient in the shortest time . The best combination obtained in experiment of electrical conductivity is 25 seeds soaked in 50 mL deionized or distilled water for 8 hours at a temperature of 30 ° C. Data were subjected to analysis of variance, the means were compared with each other by F tests and Tukey at 5 % probability, and when necessary polynomial regression analysis was performed. The electrical conductivity test performed at period eight hour proved to be more efficient in the separation of seed lots M. caesalpiniaefolia at different levels of vigor compared to the potassium test

Secagem de grãos de girassol em leito fixo e em leito de jorro

This work studies two methods for drying sunflower grains grown in the western region of Rio Grande do Norte, in the premises of the Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Norte - IFRN - Campus Apodi. This initiative was made because of the harvested grain during the harvest, being stored in sheds without any control of temperature, humidity etc. Therewith, many physical, chemical and physiological characteristics are compromised and grains lose much quality for oil production as their germination power. Taking into account that most of the stored grain is used for replanting, the studied methods include drying of grains in a thin layer using an oven with air circulation (fixed bed) and drying in a spouted bed. It was studied the drying of grains in natura, i.e., newly harvested. The fixed bed drying was carried out at temperatures of 40, 50, 60 and 70°C. Experiments in spouted bed were performed based on an experimental design, 2² + 3, with three replications at the central point, where the independent variables were grains load (1500, 2000 and 2500 g) and the temperature of the inlet air (70, 80, and 90 °C), obtaining the drying and desorption equilibrium isotherms. Previously, the characteristic curves of the bed were obtained. Both in the fixed bed as in the spouted bed, drying and desorption curves were obtained by weighing the grains throughout the experiments and measurements of water activity, respectively. The grains drying in the spouted bed showed good results with significant reduction of processing time. The models of FICK and PAGE were fitted to the experimental data, models which will represent the drying of grains both in the fixed bed as in the spouted bed. The desorption curves showed no influence of the processing temperature in the hygroscopic characteristics of the grains. The models of GAB, OSWIN and LUIKOV could well represent the desorption isotherms