Aspectos ecofisiológicos da germinação de sementes de mulateiro (Calycophyllum spruceanum Benth.) Rubiaceae
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Data
2003-02-07
Autores
Almeida, Marilene de Campos [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Informações sobre a ecofisiologia da germinação de sementes florestais amazônicas são escassas e fundamentais à compreensão do seu comportamento natural visando subsidiar programas de manejo, propagação ou estudos de regeneração natural. O objetivo deste trabalho foi estudar alguns aspectos da germinação de sementes de Calycophyllum spruceanum, espécie arbórea nativa da região amazônica. Foram avaliados o efeito da luz branca e de sombreamento, da temperatura constante e alternada, do fotoequilíbrio teórico do fitocromo, e ainda de diferentes substratos na germinação de sementes da espécie. Foi estudada também a permanência das sementes no solo sob dossel ou a pleno sol. O estudo da temperatura constante foi efetuado com intervalos de 2,5ºC a partir de 10ºC, e as melhores porcentagem, velocidade e sincronização da germinação foram obtidas sob temperatura de 20ºC, considerada ótima para a germinação da espécie. As alternâncias entre 20-25 e 15-25ºC foram as mais favoráveis para a germinação de sementes. A espécie apresentou fotoblastismo absoluto, não germinando em nenhuma das condições de escuro. As sementes germinaram em todos os fotoperíodos testados, com altas de porcentagens de germinação sob luz branca sem associação com a luz de sombreamento. A germinação foi inibida sob baixos fotoequilíbrios do fitocromo, e à medida que foi aumentado o fotoequilíbrio, houve um aumento também da porcentagem de germinação. As sementes de Calycophyllum spruceanum apresentaram resposta de fluência baixa e podem ser classificadas como sementes fotoblásticas positivas controladas pelo fitocromo B. A presença do nitrato de potássio afetou de forma negativa a germinação de suas sementes. Além disso, os resultados indicaram que podem ser utilizados para a germinação de sementes de Calycophyllum spruceanum, tanto terra vegetal, como vermiculita...
Information of ecophysiology of seed germination of Amazon forest species are of fundamental importance for the comprehension of their natural behavior for programs of propagation and forest regeneration. The aim of this paper was to study some aspects of seed germination of Calycophyllum spruceanum, arboreous species native from the Amazon region. The effect of white light and shade light, constant and alternating temperature, the theoretical photo-equilibrium of the phytochrome were evaluated, and also the effect of different substracts in the germination of seeds of this species. It was also studied the permanence of the seeds on soil under canopy or on full sun. The effect of the constant temperature was studied in the range of 10- 35,5ºC with intervals of 2,5ºC, and the best percentage, velocity and synchronization of the germination were obtained under temperature of 20ºC, considered optimal for the germination of the seeds. The alternations between 20-25 and 15-25ºC were the most favorable for the germination of seeds. The species presented absolute photoblast, with no germination in the dark. The seeds germinated in all the tested photoperiods, with high percentage germination under white light without association with the shade light. The germination was inhibited under low photoequilibrium of phytochrome, and when the photo-equilibrium was increased, increase in the germination percentage was observed. The germination of seeds of Calycophyllum spruceanum presented is controlled by low fluency response we suggest that this control is made through phytochrome B. The presence of potassium nitrate affected negatively the seed germination in Calycophyllum spruceanum. Moreover, the results indicated that soil, vermiculite or plantmax® can be used as substrate for the germination of Calycophyllum spruceanum seeds...(Complete abstract click electronic access below)
Information of ecophysiology of seed germination of Amazon forest species are of fundamental importance for the comprehension of their natural behavior for programs of propagation and forest regeneration. The aim of this paper was to study some aspects of seed germination of Calycophyllum spruceanum, arboreous species native from the Amazon region. The effect of white light and shade light, constant and alternating temperature, the theoretical photo-equilibrium of the phytochrome were evaluated, and also the effect of different substracts in the germination of seeds of this species. It was also studied the permanence of the seeds on soil under canopy or on full sun. The effect of the constant temperature was studied in the range of 10- 35,5ºC with intervals of 2,5ºC, and the best percentage, velocity and synchronization of the germination were obtained under temperature of 20ºC, considered optimal for the germination of the seeds. The alternations between 20-25 and 15-25ºC were the most favorable for the germination of seeds. The species presented absolute photoblast, with no germination in the dark. The seeds germinated in all the tested photoperiods, with high percentage germination under white light without association with the shade light. The germination was inhibited under low photoequilibrium of phytochrome, and when the photo-equilibrium was increased, increase in the germination percentage was observed. The germination of seeds of Calycophyllum spruceanum presented is controlled by low fluency response we suggest that this control is made through phytochrome B. The presence of potassium nitrate affected negatively the seed germination in Calycophyllum spruceanum. Moreover, the results indicated that soil, vermiculite or plantmax® can be used as substrate for the germination of Calycophyllum spruceanum seeds...(Complete abstract click electronic access below)
Descrição
Palavras-chave
Sementes, Seeds
Como citar
ALMEIDA, Marilene de Campos. Aspectos ecofisiológicos da germinação de sementes de mulateiro (Calycophyllum spruceanum Benth.) Rubiaceae. 2003. v, 114 f. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Biociências de Rio Claro, 2003.