Navegando por Autor "Barros, Raimundo Santos"
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Item Action of ferric and aluminium ions on the dormancy breakage of Stylosanthes humilis seeds(Acta Physiologiae Plantarum, 2011-04-05) Ribeiro, Dimas Mendes; Mapeli, Ana Maria; Delatorre, Carla Andréa; Carnelossi, Marcelo Augusto Gutierrez; Barros, Raimundo SantosDormancy of scarified seeds of Stylosanthes humilis was broken by acidic Al^3+ and Fe^3+ solutions. Fe^+3-stimulated seeds exhibited a high activity of 1-aminocyclopropane-1-carboxylate (ACC) oxidase and produced great amounts of ethylene, which showed correlated with the germination process. In addition, specific inhibitors of ethylene biosynthesis and action largely depressed the Fe^3+-stimulated germination, leading to the conclusion that the ion broke dormancy by triggering ethylene production by the seeds. By contrast, inhibitors of ethylene biosynthesis and action did not impair germination of Al^3+-stimulated dormant seeds. Moreover, ethylene production and activity of ACC oxidase of Al^3+-treated seeds was substantially decreased by inhibitors of ethylene biosynthesis, but germination kept large. Together these data suggest that ethylene biosynthesis was not required in the chain of events triggered by Al^3+ leading to dormancy breakage. Methyl viologen (MV), a reactive oxygen species-generating compound, broke dormancy of seeds to the same extent as Al^3+ did. Germination of both Al^3+- and MV-stimulated dormant seeds was inhibited by sodium selenate, an antioxidant compound; selenate, however had no effect on germination of Fe^3+-stimulated seeds. Together these data indicate that the mechanisms underlying the germination of Al^3+- and Fe^3+-treated seeds are not the same.Item Atuação das enzimas oxidativas no escurecimento causado pela injúria por frio em raízes de batata-baroa(Acta Scientiarum. Agronomy, 2008-01) Menolli, Luciana Nunes; Finger, Fernando Luiz; Puiatti, Mário; Barbosa, Janaina Miranda; Barros, Raimundo SantosNeste trabalho, as raízes de batata-baroa (Arracacia xanthorrhiza Bancroft) foram armazenas em câmaras frias, à temperatura de 5 e 10ºC, por 28 dias. A cada sete dias, as raízes eram retiradas da condição de frio, e realizada análise visual dos sintomas de injúria por frio. Em seguida, as raízes foram maceradas para determinação das atividades da peroxidase, polifenoloxidase e da concentração dos compostos fenólicos solúveis. As temperaturas de 5 e 10ºC estimularam o escurecimento externo e interno das raízes durante o armazenamento, com maior intensidade para a temperatura de 5oC. Em ambas as temperaturas, houve elevação da atividade da polifenoloxidase, peroxidase e da concentração de compostos fenólicos, a partir da exposição dos tecidos ao frio. A atividade da polifenoloxidase e a concentração de compostos fenólicos solúveis aumentaram após o 14º dia de exposição às duas temperaturas. A atividade da peroxidase aumentou até o 7º dia de armazenamento em ambas as temperaturas, mantendo-se praticamente constante, após este período, a 5 e a 10ºC, a maior atividade ocorreu no 14º dia de armazenamento. Estes resultados indicam atuação inicial da peroxidase como uma resposta inicial ao estresse causado pela colheita e o frio e posterior participação de polifenoloxidase no escurecimento enzimático e acúmulo de compostos fenólicos nos tecidos.Item Breaking dormancy of Stylosanthes humilis seeds with selenium compounds(Seed Science Research, 2008-03) Barros, Raimundo Santos; Coelho, Tales Graciano; Souza, Braulio Maia de Lana; Pinheiro, Frank James AraújoThe soluble selenium (Se) compounds selenic acid, selenious acid, selenium dioxide, selenium tetrachloride, selenomethionine, selenourea, sodium selenate and sodium selenite broke the dormancy of scarified seeds of Townsville stylo (Stylosanthes humilis HBK). Given the chemical diversity of all these molecules, it could be deduced that Se may act as a dormancy- breaking agent of Townsville stylo seeds. Sestimulated seeds produced great amounts of both ethylene and 1-aminocyclopropane-1-carboxylic acid, which correlated with the process of germination. As specific inhibitors of ethylene biosynthesis and action largely depressed this Se-stimulated germination, it was concluded that Se broke dormancy by triggering ethylene production by the seeds.Item Germination and biochemical changes in ‘Formosa’ papaya seeds treated with plant hormones(Acta Scientiarum. Agronomy, 2014-10) Zanotti, Rafael Fonsêca; Dias, Denise Cunha Fernandes dos Santos; Barros, Raimundo Santos; DaMatta, Fábio Murilo; Oliveira, Glauter LimaThis study aimed to investigate the effects of growth regulators on germination rates and biochemical compound concentrations in Carica papaya L. seeds (‘Formosa’ group). The seeds were harvested from fruits at maturation stages 3 and 5 (50 and 75% yellow fruit skin, respectively). The effects of 2-chloroethylphosphonic acid (CEPA), KNO 3 and gibberellic acid (GA 3 ) on seed germination, germination index speed, soluble sugars, starch, lipids, soluble proteins and total proteins of the papaya seeds were evaluated. The seeds from stage 5 showed a higher rate of germination 30 days after sowing than did the seeds from stage 3. Treatment with CEPA decreased seed germination, apparently due to decreased starch mobilization; the opposite response was observed following KNO 3 treatment. GA 3, alone or in combination with KNO 3, stimulated an increase in lipid mobilization. In general, with the exception of CEPA, all growth regulators tested were effective in overcoming seed dormancy, and KNO 3 was the most effective. The seeds from stage 3 fruits treated with KNO 3 or KNO 3 + GA 3 had higher rates of germination at 14 days.Item Germination of "Solo" papaya seeds treated with plant hormones(Journal of Seed Science, 2014) Zanotti, Rafael Fonsêca; Dias, Denise Cunha Fernandes dos Santos; Barros, Raimundo Santos; Silva, Laércio Junio da; Sekita, Marcelo CoelhoThe aim of this study was to investigate the effects of some plant hormones on germination of Carica papaya L. seeds of the "Solo" group taken from fruits at maturity stages 3 and 5 (50% and 75% of the fruit skin showing a yellow color). Then, the seeds were subjected to treatments involving different combinations of acid 2-chloroethylphosphonic - (CEPA 0; 5 x 10-7 and 5 x 10-4 M), GA3 (0; 10 and 50 mg / L) and KNO3 (0 or 1 M), and germination was assessed at the 14th and 30th days. Seeds from fruits at maturity stage 3 showed increased germination when treated with all growth regulators tested. KNO3 promoted a decrease in germination and in the germination speed index, especially in the seeds from stage 5. The plant hormones did not promote any increase in percentage of normal seedlings of papaya seeds. Two-Chloethylphosphonic acid (5 x 10-4 M) and the gibberellic acid applied alone in the seeds from satge 3 promoted an increase in the number of normal seedlings 14 days after sowing.Item Germination of dormant seeds of Stylosanthes humilis as promoted by ethylene accumulation in closed environments(Brazilian Journal of Plant Physiology, 2004-05) Ribeiro, Dimas Mendes; Barros, Raimundo SantosGermination of scarified dormant seeds of Townsville stylo (Stylosanthes humilis) is very low in Petri dishes, but may be appreciable in sealed Erlenmeyer flasks if ethylene accumulates in their atmospheres. When ethylene in the flask atmosphere was fixed by a mercuric perchlorate solution, emanation of the gaseous regulator and germination of dormant seeds were drastically decreased. On the other hand, ethylene produced by dormant seeds and accumulated in the flask atmosphere led to a further enhancement of ethylene accumulation and a corresponding increased seed germination. Germination of both dormant and non-dormant seeds did not occur when ethylene biosynthesis was completely blocked.Item Influence of storage temperature on Epidendrum ibaguense flowers(Acta Scientiarum. Agronomy, 2011-01) Mapeli, Ana Maria; Finger, Fernando Luiz; Barbosa, José Geraldo; Barros, Raimundo Santos; Oliveira, Lucilene Silva; Segatto, Fernanda BastosThe present work was carried out to evaluate the influence of temperature and wet-versus-dry storage on longevity, respiration and ethylene production during storage of E. ibaguense flowers. The inflorescences were harvested and stored at 5, 10, 15, 20, 25, 30, 35, and 40ºC, in water or dry, until complete senescence. Respiration increased when inflorescences were treated with wet or dry storage. The Q10 factor for this flower, at temperatures ranging from 5 to 40ºC, was similar to most fresh horticultural products, varying between 1.2 and 3.31 depending on storage temperature. Production of ethylene by the inflorescence was maximal at 20ºC for flowers maintained in water, and at 35ºC for those flowers kept dry, followed by a sharp drop in both treatments. A maximal shelf life for cut flowers was obtained when the inflorescences were stored wet at 10ºC. Symptoms of chilling were observed in flowers stored in water after six to seven days at 5ºC, showing petal wilting and necrosis of the labellum. At 40ºC, flowers stored dry showed severe petal wilting and darkening of bud petals less than one day after harvest.Item Influência da temperatura na respiração, produção de etileno e longevidade de inflorescências de esporinha(Bragantia, 2006) Finger, Fernando Luiz; Santos, Vanessa Rebouças dos; Barbosa, José Geraldo; Barros, Raimundo SantosO objetivo do trabalho foi avaliar a influência da temperatura na respiração e produção de etileno em inflorescências de esporinha (Consolida ajacis), e se a produção de CO2 poderia ser utilizada como indicador da longevidade das flores. As hastes foram colhidas, colocadas em vasos e armazenadas em temperatura de 5, 10, 15, 20, 25, 30, 35, e 40oC até a completa senescência das flores. Ocorreu variação temporal similar na respiração e produção de etileno em função da elevação da temperatura, com produção máxima de 1.854 mL CO2 kg-1 h-1 e de 11,28 mL C2H4 kg-1 h-1 a 30 oC e 40 oC, respectivamente. O fator Q10 da respiração entre 5 e 30 oC oscilou entre os valores de 1,11 e 2,89, semelhante a outros produtos hortícolas. A longevidade das flores foi inversamente proporcional ao aumento da temperatura entre 5 e 30 oC. A vida de vaso estimada da esporinha foi reduzida de 11,9 para 4,1 dias com o aumento da temperatura de armazenamento de 5 para 30 oC. A longevidade das flores mantidas a 35 e 40 oC foi semelhante a das flores armazenadas a 30 oC.Item Rendimento e algumas características físico-químicas dos frutos de seis variedades de goiabeira desenvolvidos em condições de déficit hídrico(Revista Ceres, 2000-07) Pereira, Walter Esflain; Couto, Flávio Alencar D'Araujo; Siqueira, Dalmo Lopes de; Bruckner, Claudio Horst; Cecon, Paulo Roberto; Barros, Raimundo SantosO presente trabalho foi realizado no período de fevereiro a outubro de 1995, tendo como objetivo avaliar o rendimento de frutos e algumas das suas características físico-químicas em condições de deficiência hídrica no solo, que variou de 73 a 119 mm durante cinco meses consecutivos. Os tratamentos, constituídos pelas variedades Pirassununga Vermelha, Industrial de Montes Claros, Pirassununga Branca, Brune Branca, Tetraploide de Limeira e IAC-4, foram distribuídos num delineamento de blocos casualizados, com quatro repetições. Por ocasião da colheita, foi determinado o rendimento de frutos, além do peso da matéria fresca, do diâmetro, do comprimento, da relação em espessura da polpa e do miolo, do teor de sólidos solúveis totais, da acidez titulável e do pH dos frutos. Em todas as variedades houve marcada redução no rendimento de frutos, sendo a mesma mais acentuada nas variedades Tetraploide de Limeira e IAC-4, caracterizando-as como menos tolerantes ao déficit hídrico no solo. Por ocasião da colheita, observou-se que as características tisicas do auto foram influenciadas negativamente pelo déficit hídrico no solo, sendo a variedade Tetraploide de Limeira a mais afetada, com redução de 51% no peso da matéria seca. O teor de sólidos solúveis e o pH da polpa foram semelhantes àqueles obtidos na estação chuvosa., enquanto o teor de ácido cínico foi maior.