Temperatura, luz e tolerância à dessecação na germinação de sementes de Mauritia flexuosa L.f.
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Data
2018-04-06
Autores
Almeida, Lívia Caroline Praseres de
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Universidade Estadual Paulista (Unesp)
Resumo
A espécie Mauritia flexuosa L.f., popularmente conhecida como buriti, é uma das palmeiras nativas mais apreciadas como ornamental além da importância comercial, para a sustentabilidade e para a indústria. A propagação comercial das palmeiras é por meio de sementes sendo considerada, de modo geral, lenta e desuniforme. Devido à importância desta espécie e visando elucidar aspectos que possam maximizar o processo de produção de mudas este trabalho teve como objetivo verificar o efeito de temperatura, regimes de luz e tolerância a dessecação na germinação de sementes da palmeira buriti, Mauritia flexuosa L.f. Foram realizados dois experimentos. No primeiro, estudou-se o efeito da temperatura e da luz e os tratamentos foram dispostos em esquema fatorial 6 x 2 (seis temperaturas: 20 ºC, 25 ºC, 30 ºC, 35 ºC, 20-30 ºC e 25-35 ºC combinadas com presença ou ausência de luz); foram quatro repetições de 25 sementes por parcela. No segundo, estudou-se a tolerância à dessecação e os tratamentos foram cinco teores de água nas sementes (51%, 48%, 45%, 30% e 26%) aferidos a cada três dias de um lote mantido em laboratório em condições ambiente; foram quatro repetições de 25 sementes por parcela. Nos dois experimentos o delineamento experimental foi o inteiramente casualizado. Avaliou-se a porcentagem de germinação e o Índice de Velocidade de Germinação. Os dados foram submetidos à análise de variância; as médias de temperatura e de luz foram comparadas pelo teste de Tukey (P ≤ 0.05) e para dessecação realizou-se a análise de regressão polinomial. A temperatura alternada de 20-30 ºC foi a que apresentou maior média de porcentagem de germinação (86%), e de velocidade de germinação (1,24), seguida da temperatura alternada de 25-35 ºC, com 71,5% para porcentagem de germinação e 1,25 para velocidade de germinação, independentemente da presença ou ausência de luz, sendo consideradas fotoblásticas neutras. As sementes de M. flexuosa se mostraram sensíveis à dessecação a 26% de teor de umidade.
The especies Mauritia flexuosa L.f., popularly known as buriti, is one of the native palms most appreciated as ornamental beyond commercial importance, for sustainability and for industry. The commercial propagation of palm trees is through seeds and that is in general considered slow and uneven. Due to the importance of this species and aiming to elucidate aspects that could maximize the seedling production process, this work had the objective of verifying the effect of temperature, light regimes and desiccation tolerance on the germination of the seeds of the palm buriti, Mauritia flexuosa L.f. Two experiments were carried out. In the first one, the effect of temperature and light was studied and the treatments were arranged in a 6 x 2 factorial scheme (six temperatures: 20 ºC, 25 ºC, 30 ºC, 35 ºC, 20-30 ºC and 25-35 ºC combined with presence or absence of light); were four replicates of 25 seeds per plot. In the second one, the desiccation tolerance was studied and the treatments were five water contents in the seeds (51%, 48%, 45%, 30% and 26%) measured every three days of a lot kept in the laboratory under ambient conditions; were four replicates of 25 seeds per plot. In both experiments the experimental design was completely randomized. The percentage of germination and the rate of germination were evaluated. Data were submitted to analysis of variance; the temperature and light averages were compared by the Tukey test (P ≤ 0.05) and for desiccation the polynomial regression analysis was performed. The alternating temperature of 20-30 ºC showed the highest average germination percentage (86%), germination speed (1.24), followed by alternating temperature of 25-35ºC, with 71.5% for percentage of germination and 1.25 for germination speed, regardless of the presence or absence of light, being considered neutral photoblasts. The seeds of M. flexuosa were sensitive to desiccation at 26% moisture content.
The especies Mauritia flexuosa L.f., popularly known as buriti, is one of the native palms most appreciated as ornamental beyond commercial importance, for sustainability and for industry. The commercial propagation of palm trees is through seeds and that is in general considered slow and uneven. Due to the importance of this species and aiming to elucidate aspects that could maximize the seedling production process, this work had the objective of verifying the effect of temperature, light regimes and desiccation tolerance on the germination of the seeds of the palm buriti, Mauritia flexuosa L.f. Two experiments were carried out. In the first one, the effect of temperature and light was studied and the treatments were arranged in a 6 x 2 factorial scheme (six temperatures: 20 ºC, 25 ºC, 30 ºC, 35 ºC, 20-30 ºC and 25-35 ºC combined with presence or absence of light); were four replicates of 25 seeds per plot. In the second one, the desiccation tolerance was studied and the treatments were five water contents in the seeds (51%, 48%, 45%, 30% and 26%) measured every three days of a lot kept in the laboratory under ambient conditions; were four replicates of 25 seeds per plot. In both experiments the experimental design was completely randomized. The percentage of germination and the rate of germination were evaluated. Data were submitted to analysis of variance; the temperature and light averages were compared by the Tukey test (P ≤ 0.05) and for desiccation the polynomial regression analysis was performed. The alternating temperature of 20-30 ºC showed the highest average germination percentage (86%), germination speed (1.24), followed by alternating temperature of 25-35ºC, with 71.5% for percentage of germination and 1.25 for germination speed, regardless of the presence or absence of light, being considered neutral photoblasts. The seeds of M. flexuosa were sensitive to desiccation at 26% moisture content.
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Palavras-chave
Arecaceae, Buriti, Palmeira, Arecaceae, Buriti, Palm tree