Efeito da temperatura e da luz na germinação de sementes de Acacia polyphylla DC.
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Data
2003-06-01
Autores
Araújo Neto, João C.
Aguiar, Ivor B. [UNESP]
Ferreira, Vilma M.
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Botânica de São Paulo
Resumo
Acacia polyphylla é uma espécie arbórea característica dos estádios iniciais da sucessão secundária, de grande utilidade na recuperação de áreas degradadas. O presente trabalho teve como objetivo estudar a germinação de suas sementes sob diferentes condições de temperatura e luz. Avaliaram-se os efeitos das temperaturas constantes de 15, 20, 25 e 30 ºC e alternada de 20-30 ºC, sob fotoperíodo de oito horas de luz branca. A temperatura constante de 25 ºC foi a mais adequada para a germinação e o estudo de luz foi realizado nessa temperatura. As sementes foram submetidas à ausência de luz e a fotoperíodos de 1 a 12 horas sob luz branca (alta relação vermelho/vermelho-extremo), além de fotoperíodos sob luz branca iniciados e finalizados com luz de sombreamento (baixa relação vermelho/vermelho-extremo). A porcentagem de germinação não foi afetada pelos diferentes fotoperíodos sob luz branca testados, mas fotoperíodo igual ou superior a quatro horas favoreceu o desenvolvimento inicial das plântulas. A germinação não foi afetada pela luz com baixa relação vermelho/vermelho-extremo, mas na ausência de luz as sementes germinaram em menores porcentagem e velocidade.
Acacia polyphylla (Leguminosae-Mimosoideae) is a typical tree species of secondary succession in Brazil, important for restoration of degraded areas. The purpose of this work was to evaluate the seed germination under different temperatures and light conditions. Constant (15, 20, 25 and 30 ºC) and alternating (20-30 ºC) temperatures were evaluated, at an eight hours photoperiod under white light. Constant temperature of 25 ºC was optimal and the light experiments were conducted at that temperature. Seeds were incubated in darkness and at photoperiods from 1 to 12 hours under white light (high red/far-red ratio), as well as at photoperiods under white light initiated and concluded with shade light (low red/far-red ratio). Germination percentage was not affected by the photoperiods under white light tested, but a photoperiod similar or higher than four hours was required for better initial seedling growth. Both germination percentage and speed was not affected by light of a low red/far-red ratio, but they decreased in darkness.
Acacia polyphylla (Leguminosae-Mimosoideae) is a typical tree species of secondary succession in Brazil, important for restoration of degraded areas. The purpose of this work was to evaluate the seed germination under different temperatures and light conditions. Constant (15, 20, 25 and 30 ºC) and alternating (20-30 ºC) temperatures were evaluated, at an eight hours photoperiod under white light. Constant temperature of 25 ºC was optimal and the light experiments were conducted at that temperature. Seeds were incubated in darkness and at photoperiods from 1 to 12 hours under white light (high red/far-red ratio), as well as at photoperiods under white light initiated and concluded with shade light (low red/far-red ratio). Germination percentage was not affected by the photoperiods under white light tested, but a photoperiod similar or higher than four hours was required for better initial seedling growth. Both germination percentage and speed was not affected by light of a low red/far-red ratio, but they decreased in darkness.
Descrição
Palavras-chave
Acacia polyphylla, fitocromo, germinação, luz, temperatura, Acacia polyphylla, germination, light, phytochrome, temperature
Como citar
Brazilian Journal of Botany. Sociedade Botânica de São Paulo, v. 26, n. 2, p. 249-256, 2003.