'Composicao Revista de Ciencias Sociais da Universidade Federal de Mato Grosso do Sul'
Abstract
The objective of this study was to evaluate seed metrics, optimum temperature for germination and efficiency of five pre-germination treatments for overcoming dormancy of Caesalpinia ferrea seeds. Seeds were subjected to constant temperatures of 15, 20, 25, 30 and 35°C and to the following pre-germination treatments: nicking with pincers; immersion in water for 24 hours at room temperature; scarification with sandpaper; immersion in caustic soda for 60 minutes; and control (untreated seeds). Germination rate was assessed by germination percentage and germination speed index. A completely randomized design was used with four replicates of 50 seeds each and means were compared by Tukey test at 5% probability. The best germination performance was obtained in the 15-30°C temperature range and by using chemical scarification with immersion in caustic soda, and mechanical scarification by nicking with pincers and by rubbing on sandpaper.Caracterização biométrica de sementes e influência de temperaturas e tratamentos pré-germinativos em pau-ferro
O objetivo do presente trabalho foi avaliar a biometria de sementes, a temperatura ótima e a eficiência de cinco tratamentos pré-germinativos para a superação de dormência das sementes de L. ferrea, sugeridos na literatura. As sementes foram submetidas a temperaturas constantes de 15, 20, 25, 30 e 35 ºC e aos tratamentos pré-germinativos: corte com alicate no lado oposto ao hilo, imersão em água por 24 horas em temperatura ambiente, escarificação com lixa d’água nº 4, imersão em soda cáustica por 60 minutos e a testemunha (sem tratamento). A germinabilidade foi avaliada pela porcentagem de germinação e o índice de velocidade de germinação. As características biométricas das sementes avaliadas foram: comprimento longitudinal, largura e espessura, utilizando-se paquímetro digital com precisão de 0,05 mm. O delineamento experimental foi inteiramente casualizado, e as médias foram comparadas pelo teste Tukey a 5% de probabilidade. O melhor desempenho germinativo das sementes foi obtido nas temperaturas entre 15 e 30 ºC e nos tratamentos pré-germinativos de escarificação química com imersão em soda cáustica e escarificação mecânica por meio do desponte com alicate e o atrito em lixa.
Palavras-chave: dormência, escarificação, dimensão da semente.
ABSTRACT: The objective of this study was to evaluate seed metrics, optimum temperature for germination and efficiency of five pre-germination treatments for overcoming dormancy of L. ferrea seeds. Seeds were subjected to constant temperatures of 15, 20, 25, 30 and 35°C and to the following pre-germination treatments: nicking with pincers; immersion in water for 24 hours at room temperature; scarification with sandpaper; immersion in caustic soda for 60 minutes; and control (untreated seeds). Germination rate was assessed by germination percentage and germination speed index. The biometric characteristics of the evaluated seeds were: longitudinal length, width and thickness, using a digital caliper with a precision of 0.05 mm. A completely randomized design was used with four replicates and means were compared by Tukey test at 5% probability. The best germination performance was obtained in the 15-30°C temperature range and by using chemical scarification with immersion in caustic soda, and mechanical scarification by nicking with pincers and by rubbing on sandpaper.
Keywords: dormancy; scarification; seed dimensions
