Morfologia, germinação e teor de água das sementes De Araçá-boi (Eugenia Stipitata Ssp. Sororia)

Abstract

RESUMO -O araçá-boi (Eugenia stipitata ssp. sororia McVaugh -Myrtaceae) é uma espécie frutífera originária da Amazônia Ocidental que apresenta grande potencial para a indústria de sucos e sorvetes. A morfologia das sementes é complexa e sua fisiologia pouco compreendida. Sabe-se que elas são resistentes a injúrias mecânicas e sensíveis ao dessecamento. Objetivou-se caracterizar a morfologia das sementes através da biometria, determinar o grau de umidade das sementes e descrever os eventos do processo germinativo, visando dar subsídios para o manejo das sementes e a produção de mudas. As médias de comprimento, peso fresco e peso seco das sementes foram de 1,06 cm, 0,49 g c 0,17 g, respectivamente. O teor de água encontrado nas sementes foi de 62%. A germinação das sementes é hipógea c criptocotiledonar, mostrando-se lenta e desuniforme. A germinação iniciou-se por volta de 50 dias e estendeu-se até mais de 280 dias. A plântula, com 60 dias, apresentou altura média de 13 cm e 18 folhas. As sementes apresentam alto poder de regeneração pois, mesmo quando cortadas ao meio ou na zona meristemática, foram capazes de formar plântulas.Palavras chave: Eugenia Stipitata, Germinação de Sementes, Morfologia de Sementes, Sementes Recalcitrantes, Sementes Pseudomonocotiledonares, Frutífera da Amazônia. Morphology, Germination and Water Content of Seeds of Araçá-boi (Eugenia stipitata ssp. sororia)ABSTRACT -Araçá-boi (Eugenia stipitata ssp. sororia McVaugh -Myrtaceae) is a fruit tree native to western Amazonia. It has considerable potential in the juice and ice-cream industries. Seals of araça-boi have a complex morphology and their physiology is not well understood. They arc known to be resistent to mechanical injury and sensitive to drying. This study undertakes a biometric characterization of seed morphology, determines seed water content and describes the germination process, with a view to aiding seed handling and seedling production. Average seed length, fresh and dry weight were found to be 1.06 cm, 0.49 g and 0.17 g respectively. The water content was 62%. Germination, which is hypogcal and cryptocotyledonous, was observed to be slow and far from uniform; the first seeds germinated after about 50 days, while others took longer than 280 days. Sixty-day-old seedlings had an average height of 13 cm and had 18 leaves. Seeds showed a high capacity for regeneration; even when cut in the middle or in the meristematic zone, they still formed seedlings.

Water potential and viability of seeds of Eugenia (Myrtaceae), a tropical tree species, based upon different levels of drying

“…Seeds of many Brazilian tropical tree species in the genus Eugenia (Myrtaceae) show high water content at shedding and have been considered to be sensitive to desiccation. However, among Eugenia seeds, there are different desiccation sensitivity levels based on the water content, as reported by different authors Anjos and Ferraz 1999;Andrade and Ferreira 2000;Andrade et al 2003;Delgado and Barbedo 2007;Masetto et al 2008). Delgado and Barbedo (2007), for example, identified three different levels of critical water content (described as fresh mass basis) for the seeds of six species of Eugenia, from 65 (the most sensitive seeds) to 45% (the least sensitive seeds).…”

Germination inhibits the growth of new roots and seedlings in Eugenia uniflora and Eugenia brasiliensis

“…Seeds of E. stipitata ssp. sororia, which also have the ability to regenerate embryos after fractionation, had seedling development from the seed area opposite to the damaged one, where apparently was the meristematic zone (Anjos and Ferraz, 1999). However, in the seed complementary fraction, seedlings were formed on the cut surface, which shows some polarity in mobilizing hormones.…”

Osmopriming duration in Araçá-boi seeds germination

“…The seeds germination are hypogeal, cryptocotylar and usually occurs at 50 to 280 days from the beginning to the end of the germination process (ANJOS and FERRAZ, 1999). Some studies presented that seeds dormancy are one of the major cause of long germination period, as well as the slowness in the seedling emergence of this specie.…”