Temperaturas para a germinação de sementes de capixingui (Croton floribundus - Spreng - Euphorbiaceae)
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Data
2006-12-01
Autores
Abdo, Maria Teresa Vilela Nogueira [UNESP]
Paula, Rinaldo César de [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Associação Brasileira de Tecnologia de Sementes (ABRATES)
Resumo
O presente trabalho objetivou avaliar a influência de diferentes temperaturas e da imersão em água na germinação de sementes de capixingui (Croton floribundus Spreng). Inicialmente, as sementes foram submetidas à germinação a 15, 20, 25, 30, 35, 40, 20-30 e 25-35ºC, com e sem imersão das mesmas em água fria (temperatura ambiente) por duas horas. Posteriormente, sementes sem imersão prévia em água fria foram submetidas à germinação a 20-25, 25-30, 30-35, 20-30, 25-35 e 20-35ºC. Foram avaliadas a porcentagem e a velocidade de germinação das sementes, a matéria seca e o comprimento de plântulas. Os dados foram submetidos à análise de variância, no delineamento inteiramente casualizado (DIC) e esquema fatorial 8 x 2 no primeiro experimento e no DIC com seis tratamentos no segundo experimento, com quatro repetições de 25 sementes, seguido da comparação de médias (Tukey a 5%). Não houve germinação a 15, 20 e 40ºC e esta foi mínima a 25ºC. As temperaturas alternadas de 20-30 e de 25-35ºC favoreceram o processo germinativo. A imersão das sementes em água fria não favoreceu a taxa de germinação. No segundo experimento, a maior germinação ocorreu a 20-30ºC. Assim, pode-se recomendar a temperatura de 20-30ºC para a condução do teste de germinação de sementes de capixingui, o qual pode ser encerrado aos 28 dias.
The aim of this research was to evaluate the influence of different temperatures, constant and alternating, on the germination of Croton floribundus Spreng (Euphorbiaceae) seeds and also the efficiency of a previous soaking treatment in cold water (room temperature). In the first test, the seeds were submitted to the standard germination test at the following temperatures 15, 20, 25, 30, 35, 40, 20-30 and 25-35ºC, with and without previous soaking treatment. In the second test, the seeds were submitted to germination at temperatures of 20-25, 25-30, 30-35, 20-30, 25-35 and 20-35ºC. The characteristics evaluated were the percentage and speed of germination and seedling mass and length, with four replications of 25 seeds. A completely randomized design was used with 8x2 treatments in the first essay and six treatments in the second. The averages were compared by the Tukey test (P<0.05). In the first experiment, germination was not observed at 15, 20 and 40ºC; at 25ºC the germination was minimum; high germination was observed at the alternating temperatures. Soaking in cold water did not improve the germination. In the second experiment, the highest germination rate was observed at 20-30ºC. Thus, the standard germination test can be conducted at 20-30ºC for 28 days.
The aim of this research was to evaluate the influence of different temperatures, constant and alternating, on the germination of Croton floribundus Spreng (Euphorbiaceae) seeds and also the efficiency of a previous soaking treatment in cold water (room temperature). In the first test, the seeds were submitted to the standard germination test at the following temperatures 15, 20, 25, 30, 35, 40, 20-30 and 25-35ºC, with and without previous soaking treatment. In the second test, the seeds were submitted to germination at temperatures of 20-25, 25-30, 30-35, 20-30, 25-35 and 20-35ºC. The characteristics evaluated were the percentage and speed of germination and seedling mass and length, with four replications of 25 seeds. A completely randomized design was used with 8x2 treatments in the first essay and six treatments in the second. The averages were compared by the Tukey test (P<0.05). In the first experiment, germination was not observed at 15, 20 and 40ºC; at 25ºC the germination was minimum; high germination was observed at the alternating temperatures. Soaking in cold water did not improve the germination. In the second experiment, the highest germination rate was observed at 20-30ºC. Thus, the standard germination test can be conducted at 20-30ºC for 28 days.
Descrição
Palavras-chave
Forest seed, dormancy, seed analysis, viability, Semente florestal, dormência, Análise de sementes, viabilidade
Como citar
Revista Brasileira de Sementes. Associação Brasileira de Tecnologia de Sementes, v. 28, n. 3, p. 135-140, 2006.