The search for tests that offer fast and reliable information on the physiological potential of seeds is of fundamental importance for quality control programs. The aim of this study was to evaluate the efficiency of the potassium leaching test in identification of different vigor levels of popcorn seed lots. Five seed lots of the hybrids AP8203 and AP4512 were tested for moisture content, and physiological quality was evaluated by tests of germination, first count of germination, and seedling emergence in the field. These results were compared to variations in the potassium leaching test (temperatures of 25 °C and 30 °C, volumes of 50 mL and 75 mL of water, fifty and one hundred seeds, and periods of 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 4 h and 5 h). Results showed that the potassium leaching test is efficient in separating the popcorn seed lots regarding physiological potential, and the most adequate conditions for this test are the use of fifty seeds with 50 mL of water for two hours at 30 ºC.

Electrical conductivity of coffee seeds in function of the number of seeds and imbibing period Condutividade elétrica de sementes de café em função do número de sementes e período de embebição

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Carrot seeds exhibit irregular vigor due to the wide blooming period of the crop. Results from germination tests are insufficient to evaluate the physiological potential. Thus, vigor tests are used in combination with germination tests. The objective of this work was to evaluate the quality of carrot seeds from different umbel order and the electrical conductivity under different temperatures and imbibing periods. Carrot seeds from cultivar Brasilia were used to perform the experiments. Content of water, the first and the final score of the germination test, index of germination rate, and length of roots and of the aerial portion were determined in the initial characterization. The electrical conductivity test was completed with replicates containing 50 seeds, in 25 mL deionized water at 20, 25 and 30oC. Evaluations were performed with 2, 4, 6, 8, 12 and 24 hours of imbibing period. The experiment was accomplished under a completely random statistical design. The quality of carrot seeds varied according to the umbel order. Seeds of secondary umbels showed better physiological quality. The electrical conductivity test is efficient to evaluate the vigor of carrot seeds with 8 hours of imbibing period at 25°C.

Aristolochia elegans é uma planta muito apreciada por seus atrativos paisagísticos, sendo amplamente utilizada como espécie ornamental, porém, informações sobre o seu comportamento germinativo são escassas. Assim, objetivou-se avaliar os efeitos de diferentes temperaturas e concentrações de giberelina na germinação de sementes de A. elegans. As sementes foram imersas em solução de giberelina nas concentrações de 100, 200 e 300 mg L-1, posteriormente foram semeadas sobre papel mata-borrão e transferidas para os germinadores com temperaturas constantes de 15, 20, 25, 30 e 35ºC. Não houve efeito de interação ou efeito isolado de giberelina, apenas efeito isolado da temperatura em todos os parâmetros avaliados. Para a germinação, a curva obteve uma resposta máxima na temperatura estimada em 29,14˚C, com 75% de germinação e a temperatura mínima estimada em 16,9˚C. A velocidade média de germinação cresceu com a elevação da temperatura até um máximo de 29ºC, e em temperaturas acima desse valor, a velocidade diminuiu. Conclui-se que a temperatura aproximada de 29,4˚C permite a melhor germinação, enquanto temperatura abaixo de 16,9˚C, temperatura mínima estimada, não ocorre a germinação das sementes e que não há efeito da giberelina nos parâmetros de germinação quando aplicadas doses entre 100 e 300 mg L-1.

Gherkin seeds usually show irregular physiological quality. Seed production requires fast and reliable tests to evaluate seed quality. Germination test is considered a recognized analysis method; however, seed technology has pursuit the improvement of vigor tests aiming the evaluation of seed’s physiological potential. Thus, the objective of this work was to evaluate procedures to perform the test of accelerated aging and determine the physiological and sanitary potential of gherkin seeds. Four seed lots of cultivar Liso Calcuta were used in the study. To evaluate the initial physiological quality the water content was determined and germination and emergence tests, as well as indices of germination speed and emergence speed were used. The accelerated aging test was performed as traditionally and with saturated saline solution, with 48, 72 and 96 hours, at temperatures of 41oC and 45oC. After aging, the water content was determined, and seeds’ germination and sanity tests were performed. The experiment was set under a completely random design in factorial 4x3x2 (lots x aging periods x temperatures). The standard accelerated aging test and the test with saturated saline solution at 41oC for 96 hours were efficient to evaluate the vigor of gherkin seeds. Saturated saline solution provides uniform water absorption and deterioration in gherkin seeds, allowing to discriminate seed lots in different vigor levels. The salinity test after accelerated aging with saline solution reduces the incidence of some fungi.

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RESUMOO substrato deve ser escolhido para proporcionar condições adequadas para a germinação e o desenvolvimento de plantas, garantindo o sucesso do empreendimento. Assim, objetivou-se estudar cinco substratos para germinação e produção de mudas de maracujá e mamão formosa. No experimento foram utilizados cinco tratamentos: S1; S2; S3; S4 e S5, variando entre substratos comerciais e inertes. Foram avaliados: porcentagem de emergência (E), índice de velocidade de emergência (IVE); tempo médio de emergência (TME), velocidade de emergência (V), altura de plantas aos 15 (Alt15) e 30 dias (Alt30), massa seca da parte aérea (MSPA), raiz (MSR) e total (MST), razão MSPA/MSR, comprimento da raiz (CR), diâmetro do caule (DM) e o índice de qualidade de Dickson (IQD).