Pré-embebição: efeitos na germinação; crescimento de plântulas e teor de cafeína em sementes de cafeeiro
Data
2007-01
Título da Revista
ISSN da Revista
Título de Volume
Editor
Editora UFLA
Resumo
Sementes de cafeeiro (Coffea arabica L.) contêm de 1% a 2% de cafeína, um alcalóide altamente solúvel em água, que inibe a germinação de sementes de várias espécies. Para avaliar os efeitos de tratamentos de pré-embebição e de lavagem em água corrente sobre o desempenho fisiológico e o teor de cafeína das sementes de cafeeiro, este trabalho foi realizado com os seguintes tratamentos: pré-embebição em água sob agitação, por 6, 12 e 24 horas, seguida de lavagem rápida em água corrente; lavagem em água corrente por 6, 12 e 24 horas; pré-embebição em água por 6, 12, 24, 48, 72 e 96 horas, seguida de lavagem rápida em água corrente; e sementes secas sem pergaminho. Foram avaliados: porcentagem de protrusão radicular, de plântulas normais aos 30 dias, de folhas cotiledonares aos 45 dias e índice de velocidade de germinação. Os teores de cafeína, de aminoácidos e de açúcares solúveis totais presentes nas soluções de embebição, bem como os teores de cafeína nas sementes, foram também determinados. Não houve diferenças significativas nos valores de protrusão radicular aos quinze dias. Maiores valores de protrusão radicular aos sete dias e de índice de velocidade de germinação foram observados em sementes submetidas à pré-embebição em água por 48, 72 e 96 horas. Maiores porcentagens de plântulas com folhas cotiledonares aos 45 dias foram observadas em sementes pré-embebidas por 24 e 48 horas e nesses tratamentos houve reduções significativas de cafeína, entre 10% e 18%, respectivamente. No entanto, a ação detrimental da cafeína no desempenho fisiológico de sementes de cafeeiro associado aos tratamentos de pré-embebição deve ser mais bem investigada.
Coffee seeds (Coffea arabica L.) contains from 1% to 2% of caffeine, a highly water-soluble alkaloid, which inhibits germination of several species. This work was undertaken to evaluate the effects of treatments of pre-imbibition and running water washing on physiological performance and caffeine content of coffee seeds, with the following treatments: pre-imbibition in water under stirring for 6, 12 and 24 hours, followed by fast washing in running water; washing in running water for 6, 12 and 24 hours; pre-imbibition in water for 6, 12, 24, 48, 72 and 96 hours, followed by fast washing in running water, and dry seeds witout parchment. The percentage of root protrusion, of normal seedlings at 30 days, of cotiledonary leaves at 45 days and of the root protrusion velocity index were evaluated. The contents of caffeine, aminoacids and total soluble sugars present in the imbibition solution, as well as the caffeine contents in seeds were also determinated. There were no significant differences in the root protrusion evaluation at fifteen days and the best treatments, evaluated by means of radicle protrusion at seven days and of index of germination velocity, were pre-imbibited in water for 48, 72 and 96 hours. As to the percentage of seedlings with cotyledonary leaves opened at 45 days, the pre-imbibition treatments for both 24 and 48 hours provided the best physiological performances of seeds, and in these treatments there were significant reductions of caffeine content between 10% and 18%, respectively. Nevertheless, the detrimental action of caffeine on the physiological performance of coffee seeds, associated with the pre-imbibition treatments should be better investigated.
Coffee seeds (Coffea arabica L.) contains from 1% to 2% of caffeine, a highly water-soluble alkaloid, which inhibits germination of several species. This work was undertaken to evaluate the effects of treatments of pre-imbibition and running water washing on physiological performance and caffeine content of coffee seeds, with the following treatments: pre-imbibition in water under stirring for 6, 12 and 24 hours, followed by fast washing in running water; washing in running water for 6, 12 and 24 hours; pre-imbibition in water for 6, 12, 24, 48, 72 and 96 hours, followed by fast washing in running water, and dry seeds witout parchment. The percentage of root protrusion, of normal seedlings at 30 days, of cotiledonary leaves at 45 days and of the root protrusion velocity index were evaluated. The contents of caffeine, aminoacids and total soluble sugars present in the imbibition solution, as well as the caffeine contents in seeds were also determinated. There were no significant differences in the root protrusion evaluation at fifteen days and the best treatments, evaluated by means of radicle protrusion at seven days and of index of germination velocity, were pre-imbibited in water for 48, 72 and 96 hours. As to the percentage of seedlings with cotyledonary leaves opened at 45 days, the pre-imbibition treatments for both 24 and 48 hours provided the best physiological performances of seeds, and in these treatments there were significant reductions of caffeine content between 10% and 18%, respectively. Nevertheless, the detrimental action of caffeine on the physiological performance of coffee seeds, associated with the pre-imbibition treatments should be better investigated.
Descrição
Palavras-chave
Qualidade fisiológica, Coffea arabica, Cafeína, Lixiviação
Citação
ROSA, S. D. V. F. et al. Pré-embebição: efeitos na germinação; crescimento de plântulas e teor de cafeína em sementes de cafeeiro. Coffee Science, Lavras, v. 2, n. 1, p. 69-78, jan./jun. 2007.