Marcia Terezinha Ramos de Oliveira

Qualidade fisiológica de semente de mamão em função da secagem e do armazenamento

A literatura apresenta resultados conflitantes sobre a manutencao do potencial fisiologico de semente de mamao armazenada por longos periodos com baixo teor de agua e em ambientes a baixas temperaturas. Neste trabalho, sementes de mamao do cultivar UENF-CALIMAN 01 foram secadas a sombra ate teor de agua de 12,6% b.u. e submetidas a secagem complementar a 37o C, em secador de bandejas, ate atingir teor de agua de 7,7% b.u. A germinacao e o vigor da semente, estimado pela contagem de plântulas normais fortes aos 14 dias, foram avaliados depois de submetidos aos dois processos de secagem e aos quatro e oito meses de armazenamento, em embalagem hermetica a 15o C. O vigor da semente, inicialmente de cerca de 46%, aumentou para 77%, depois de quatro meses de armazenamento. O percentual de germinacao, depois dos processos de secagem, foi de 75%, aumentando para 87% e declinando para 66%, aos quatro e oito meses de armazenamento, respectivamente. Os resultados obtidos no presente trabalho indicam que o comportamento da semente de mamao se aproxima mais daquele observado em sementes ortodoxas, que tem sua viabilidade extendida pela reducao simultânea do teor de agua e da temperatura, durante o armazenamento.

Efeito da temperatura do ar de secagem sobre o teor e a composição química do óleo essencial de Pectis brevipedunculata

Leaves and flower heads of P. brevipedunculata were submitted to four drying-air temperatures (room temperature, 40, 50 and 60 oC). Room temperature (approximately 30 oC) and higher temperature drying (50 and 60 oC) had a deleterious effect on the essential oil content. The recommended drying-air temperature for the species is 40 oC for it results in the same amount of essential oil observed in fresh cut plants. Overall, 13 components accounting for more than 92% of the total composition were identified. Citral was the major component, followed by α-pinene and limonene. The essential oil showed high toxicity against Artemia salina larvae.

Physiological quality and storability of carambola seeds

This study was conducted to determine the physiological quality of carambola seeds convectively dried at 38 oC, at the end of germination tests in paper rolls and lasting 84 days. Seed storability using two types of packaging, water vapour permeable and impermeable, under two storage conditions, ambient at 25 oC and 61% relative humidity, and inside a 10 oC refrigerated chamber with relative humidity of 82%, was also assessed for periods of 90 and 180 days. Mean germination percentage of fresh seeds was 87%. The results obtained through germination testing showed that carambola seeds can be stored for 90 or 180 days at 10 oC, or for 90 days at ambient conditions, in vacuum-sealed packaging, without impairing their physiological quality. Seeds may also be stored for 90 days in water vapour-permeable packaging under refrigeration. Vigour estimated through the germination speed index and the mean time of germination was consistently higher for seeds stored in vacuum-sealed packaging, irrespective of storage time and temperature.

Germinação e vigor de sementes de mamão (Carica papaya L.) cv. Golden secadas em altas temperaturas

This study investigates the immediate and latent effects of high drying-air temperatures on the physiological quality of Golden papaya seeds. Thin-layer convective drying tests were conducted employing two levels of drying-air temperature, 50 and 58oC, and a single level of dry-airflow rate, 1.00kg s-1 m-2. Upon removal from the dryer, seeds were hermetically stored at 15oC for 90 and 180 days. High drying-air temperatures had an immediate deleterious effect on seed vigour. Analysis of the latent effects revealed that best vigour results were obtained for seeds dried at 58oC and stored for 180 days at 15oC. Germination percentage immediately after drying was reduced for seeds dried at 50oC only. Germination of the seeds submitted to other treatments was not affected by drying-air temperature or storage period, when compared to the values obtained for fresh seeds.

Efeito da secagem por convecção na germinação de sementes de carambola

Information on the physiological potential of carambola seeds is practically inexistent although interest in carambola production has been increasing steadily over recent years. The objective of this study was to investigate the immediate effect of convective drying at 38 oC on seed germination and vigour. Germination tests under controlled laboratory conditions were done using rolled paper towels, whereas tests in a protected environment were done using a lightweight, commercial seed-starting medium. In a protected environment, convective drying increased the percentage germination from 74% (fresh seeds) to 98% (dried seeds). Vigour, as estimated from the germination speed index and the mean time of germination, did not vary, irrespective of drying. The curves representing plant growth rate and the dry mass accumulation rate of the aerial parts of the plant, show that seeds which had been dried gave rise to more vigorous plants.

Características biométricas e físico-químicas do fruto, morfologia da semente e da plântula de Averrhoa carambola l. (oxalidaceae)

Este trabalho foi realizado com o objetivo de caracterizar os frutos, estudar a morfologia externa e interna das sementes e ilustrar o desenvolvimento de plântulas e de plantas jovens de Averrhoa carambola. Os frutos foram distribuidos em tres categorias, de acordo com o estadio de maturacao (maduros, intermediarios e verdes), e em tres subcategorias de acordo com o tamanho (grande, medio e pequeno). Para a caracterizacao dos frutos determinaram-se as dimensoes, a massa, o numero de sementes, a cor, o pH e os teores de agua e de solidos soluveis totais (SST) da polpa. Para a caracterizacao morfologica das sementes foi medido o comprimento, a largura, a espessura, a massa e determinada as dimensoes do endosperma, cotiledone e eixo hipocotilo radicular. Determinou-se, tambem, a massa de 1000 sementes. Os frutos maduros e grandes apresentam dimensoes e teor de SST proximos aos encontrados em frutos comerciais, no entanto, com menor luminosidade e maior intensidade de cor, com predominância do alaranjado. O endosperma e o orgao de reserva das sementes, que exibem cotiledones de cor branca, com leve tom esverdeado nos bordos; a germinacao e epigea e a protrusao da raiz primaria inicia-se 21 dias apos a semeadura. Os dados obtidos na avaliacao das caracteristicas das sementes apresentam desvios-padrao baixos, indicando que os valores medidos podem ser usados em estudos taxonomicos e na analise da germinacao.

Vigour of carambola seeds as affected by drying and storage

This study evaluated the immediate and latent effects of drying-air temperature on the vigour of carambola seeds determined under controlled laboratory conditions. Seed vigour was assessed through the germination speed index and the mean time to germinate. A continuous-flow thin-layer prototype dryer with an air inlet providing a tangential airflow was used. Tests were conducted employing three levels of drying-air temperature (30, 34, and 38 °C), one level of dry air flow rate (1.123 kg s-1 m-2), and six storage periods (0, 45, 60, 90, 180 and 270 days). Seeds were stored at 15 °C. No immediate effect of drying-air temperature on seed vigour has been observed. Evaluation of the effect of storage conditions on seed quality revealed that higher values of germination speed index were observed for seeds dried at 38 °C and stored for 180 days. Seed vigour, estimated through the mean time to germinate, irrespective of drying-air temperature, was higher for seeds stored for 90 and 270 days. Due to ambiguity of the results, the two indices should be used with caution to distinguish the physiological quality of different lots of carambola seeds.