Coffee Science
URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3355
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Item Ultrastructural damage in coffee seeds exposed to drying and to subzero (°C) temperatures(Editora UFLA, 2020) Coelho, Stefânia Vilas Boas; Rosa, Sttela Dellyzete Veiga Franco da; Clemente, Aline da Consolação Sampaio; Lacerda, Laura Nardelli Castanheira; Silva, Luciano Coutinho; Fantazzini, Tatiana Botelho; Ribeiro, Fernando Augusto Sales; Castro, Elisa de MeloDuring drying and freezing, protective mechanisms act to maintain seed physiological quality. Some of these mechanisms contribute to the integrity of cell membranes. The damage caused to cell membranes due to cell stress can be seen in ultrastructural studies, comparing these results to those of physiological evaluation. The aim of this study was to investigate ultrastructural changes in endosperm cells of coffee seeds brought about by drying and by exposure to low temperatures. Seeds of Coffea arabica were dried in silica gel to moisture contents of 40, 20, and 5 % (wb) and brought to equilibrium at temperatures of 10, -20, and -86 oC. Germination, vigor, and tetrazolium tests were performed for evaluation of seed physiological quality. Ultrastructural damage was analyzed by scanning electron microscopy. Coffee seeds with 40% moisture content have whole, swollen, and expanded cells, with a filled lumen and without signs of damage. The physiological and ultrastructural quality of seeds exposed to below zero temperatures with 40% moisture content is compromised. They have null germination and empty cells, indicating leakage of cell content. Drying of coffee seeds leads to uniform contraction of inner cell content. Drying of coffee seeds to 5% moisture content leads to intense contraction of cell volume, with physiological and ultrastructural damage.Item Big Coffee VL.: Seed desiccation tolerance, sieve classification, and physiological quality(Editora UFLA, 2018-10) Souza, Ana Cristina de; Rosa, Sttela Dellyzete Veiga Franco da; Vilela, Amanda Lima; Figueiredo, Madeleine Alves de; Vilela, Ana Luiza de Oliveira; Stéphano Filho, Ricardo; Carvalho, Milene Alves de FigueiredoA coffee plant producing large fruit, seeds, and leaves in relation to conventional coffee plants, possibly generated by genetic mutation, was named Big Coffee VL. Seeds of this coffee plant were classified by size and used to establish the crop, whose progenies were designated as Big Coffee VL. large, Big Coffee VL. medium, and Big Coffee VL. small. The aim in this study was to investigate desiccation tolerance, together with size classification, and evaluate the physiological quality of the seeds of this progeny. Seeds of each type of Big Coffee VL. and of the cultivar Topázio were collected. High moisture seeds and seeds dried to 11% moisture content were evaluated to assess desiccation tolerance. Dried seeds of each Big Coffee VL. progeny and of the Topázio cultivar were classified by size in sieve testing using oblong screens for separation of peaberry seeds, and circular sieves from 22 to 12 for separation of flat seeds. All seeds were subjected to physiological evaluation through the germination test and determination of seedling dry matter. A completely randomized experimental design (CRD) was used; results were subjected to analysis of variance and means compared by the Scott-Knott test. Big Coffee VL. seeds tolerate desiccation to moisture content of 11% wet basis. Seeds of the Topázio cultivar have better physiological performance than seeds of the Big Coffee VL progenies. The bigger the seeds of Big Coffee VL., the better their physiological performance, exhibiting greater seedling dry matter.Item Pré-embebição: efeitos na germinação; crescimento de plântulas e teor de cafeína em sementes de cafeeiro(Editora UFLA, 2007-01) Rosa, Sttela Dellyzete Veiga Franco da; Mazzafera, Paulo; Guimarães, Renato Mendes; Veiga, André Delly; Veiga, Adriano DellySementes de cafeeiro (Coffea arabica L.) contêm de 1% a 2% de cafeína, um alcalóide altamente solúvel em água, que inibe a germinação de sementes de várias espécies. Para avaliar os efeitos de tratamentos de pré-embebição e de lavagem em água corrente sobre o desempenho fisiológico e o teor de cafeína das sementes de cafeeiro, este trabalho foi realizado com os seguintes tratamentos: pré-embebição em água sob agitação, por 6, 12 e 24 horas, seguida de lavagem rápida em água corrente; lavagem em água corrente por 6, 12 e 24 horas; pré-embebição em água por 6, 12, 24, 48, 72 e 96 horas, seguida de lavagem rápida em água corrente; e sementes secas sem pergaminho. Foram avaliados: porcentagem de protrusão radicular, de plântulas normais aos 30 dias, de folhas cotiledonares aos 45 dias e índice de velocidade de germinação. Os teores de cafeína, de aminoácidos e de açúcares solúveis totais presentes nas soluções de embebição, bem como os teores de cafeína nas sementes, foram também determinados. Não houve diferenças significativas nos valores de protrusão radicular aos quinze dias. Maiores valores de protrusão radicular aos sete dias e de índice de velocidade de germinação foram observados em sementes submetidas à pré-embebição em água por 48, 72 e 96 horas. Maiores porcentagens de plântulas com folhas cotiledonares aos 45 dias foram observadas em sementes pré-embebidas por 24 e 48 horas e nesses tratamentos houve reduções significativas de cafeína, entre 10% e 18%, respectivamente. No entanto, a ação detrimental da cafeína no desempenho fisiológico de sementes de cafeeiro associado aos tratamentos de pré-embebição deve ser mais bem investigada.