Morfologia e germinação de sementes de Caryota urens (Lam.) Mart. (Arecaceae)
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Data
2007-02-07
Autores
Pimenta, Ricardo Soares [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Caryota urens (Lam.) Mart., embora muito utilizada, há poucas informações sobre produção de mudas; desta forma, este trabalho teve como objetivo descrever a morfologia do diásporo (semente com o endocarpo aderido) e da plântula, bem como, estudar a interação entre temperatura e reposição de água em diferentes substratos. O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 6 x 3, (seis temperaturas: 20, 25, 30, 35, 20-30 e 25-35°C; fotoperíodo de 12 horas e três reposições de água: areia - 50, 60 e 70%; esfagno e vermiculita - 80, 100 e 120%), com 4 repetições de 20 sementes. Anotou-se a cada dois dias o número de sementes que emitiram o botão germinativo para determinação da porcentagem de germinação e Índice de Velocidade de Germinação. Os dados foram analisados estatisticamente e as médias comparadas pelo Teste de Tukey (5%). As sementes são albuminosas, com endosperma rígido ocupando quase todo o interior do diásporo. O embrião é lateral, periférico e pouco diferenciado. Por meio da abertura de um opérculo circular no endocarpo, emerge o pecíolo cotiledonar que cresce e dilata em sua extremidade, originando a raiz primária e a parte aérea (plúmula), composta pela primeira folha juvenil completa (eófilo) e pinada (com 2 pinas de forma triangular). As temperaturas de 25ºC e 30ºC foram as mais adequadas e ainda, 25-35ºC, em esfagno e areia, independentemente da reposição de água. A porcentagem de germinação não foi influenciada pelas diferentes taxas de reposição de água, independentemente da temperatura. Em vermiculita, a germinação foi mais rápida repondo 100 e 120% de água.
The palm tree Caryota urens (Lam.) Mart. is extensively used but poorly studied. The objective of this work was to describe the disseminule (the seed with endocarp attached to it) morphology and to evaluate the effects of the temperature, water reposition regimes, and types of substratum on seed germination. The experiment was set according to a completely random design in a factorial arrangement by which the seeds were set to germinate in a 12 hour photoperiod under combinations of different temperatures (the constant temperatures of 20, 25, 30, and 35ºC and the alternate temperatures of 20-30 and 25-35ºC) and different water reposition regimes (at 50, 60, and 70% in sand and at 80, 100, and 120%, in sphagnum and vermiculite). Each treatment was replicated 4 times. The number of germinated seeds (germination button) was counted every two days these data being also used to calculate the germination speed index. The seeds were found to be of the albuminous type with a hard endosperm occupying almost the entire inner space of the disseminule. The peripheral embryo occupies a lateral position and is little differentiated. The cotyledonous petiole emerges through a circular operculum in the endocarp, grows and enlarges its extremity, from which the aerial part (plumule) and the primary root are originated. The plumule is formed by the first juvenile complete bipinnate leaf (the eophylle, with two triangular leaves which gives them a tail fin appearance). In any of the used substrata the temperatures of 25 and 30ºC were the best for the germination of seeds; for sphagnum or sand, independently of the water reposition regime, temperatures of 25-35ºC too gave good results. Seed germination percentage was not affected by the different water reposition regimes independently of temperature. In vermiculite, germination is faster when water reposition takes place at 100 and 120%.
The palm tree Caryota urens (Lam.) Mart. is extensively used but poorly studied. The objective of this work was to describe the disseminule (the seed with endocarp attached to it) morphology and to evaluate the effects of the temperature, water reposition regimes, and types of substratum on seed germination. The experiment was set according to a completely random design in a factorial arrangement by which the seeds were set to germinate in a 12 hour photoperiod under combinations of different temperatures (the constant temperatures of 20, 25, 30, and 35ºC and the alternate temperatures of 20-30 and 25-35ºC) and different water reposition regimes (at 50, 60, and 70% in sand and at 80, 100, and 120%, in sphagnum and vermiculite). Each treatment was replicated 4 times. The number of germinated seeds (germination button) was counted every two days these data being also used to calculate the germination speed index. The seeds were found to be of the albuminous type with a hard endosperm occupying almost the entire inner space of the disseminule. The peripheral embryo occupies a lateral position and is little differentiated. The cotyledonous petiole emerges through a circular operculum in the endocarp, grows and enlarges its extremity, from which the aerial part (plumule) and the primary root are originated. The plumule is formed by the first juvenile complete bipinnate leaf (the eophylle, with two triangular leaves which gives them a tail fin appearance). In any of the used substrata the temperatures of 25 and 30ºC were the best for the germination of seeds; for sphagnum or sand, independently of the water reposition regime, temperatures of 25-35ºC too gave good results. Seed germination percentage was not affected by the different water reposition regimes independently of temperature. In vermiculite, germination is faster when water reposition takes place at 100 and 120%.
Descrição
Palavras-chave
Palmeira - Semente, Plantas - Efeito da temperatura, Caryota urens, Plântula, Palmeira-rabo-de-peixe, Toddy palm, Plants, Effect of temperature
Como citar
PIMENTA, Ricardo Soares. Morfologia e germinação de sementes de Caryota urens (Lam.) Mart. (Arecaceae). 2007. iii, 29 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2007.