Ciência e Agrotecnologia
URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/9885
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Item Trolox equivalent antioxidant capacity of Coffea arabica L. seeds(Editora UFLA, 2022-08-08) Ferreira, Iara Alves; Fávaris, Nathália Aparecida Bragança; Rosa, Sttela Dellyzete Veiga Franco da; Coelho, Stefânia Vilas Boas; Ricaldoni, Marcela Andreotti; Costa, Marina ChagasThe causes of the low desiccation tolerance and low longevity of coffee seeds have not yet been fully elucidated, and a full understanding of their complex physiology is of great interest. Among several alternatives, the loss of antioxidant capacity in seeds may be related to their rapid loss in quality during storage. The objective of this study was to determine the total antioxidant capacity of coffee harvested at different ripeness stages before and after the storage of seeds with different water contents and to relate antioxidant capacity to physiological quality. Seeds in the greenish-yellow or cherry stages, recently harvested or stored for nine months at 10 °C with 40, 30, 20 and 12% water content (wet basis - wb), were submitted to physiological and biochemical quality evaluations, and the Trolox equivalent antioxidant capacity (TEAC) was determined. The germination and root protrusion of coffee seeds from greenish-yellow and cherry fruits were not affected by drying, but seeds harvested at physiological maturity had greater vigor when the moisture content was lower. The quality of coffee seeds decreased during storage, and this decrease was greater in seeds stored with higher water contents. Coffee seeds in the greenish-yellow stage had a higher antioxidant capacity than those in the cherry stage when recently harvested, but there was a substantial reduction in this capacity during storage at both maturation stages. Coffee seed deterioration is related to a reduction in antioxidant capacity, and the isoenzymatic profiles of the antioxidant process are little affected by the seed maturation stage. The deterioration of coffee seeds during storage is related to a reduction in their total antioxidant capacity, regardless of their maturation stage, being more pronounced in the greenish-yellow stageItem Crescimento e características anatômicas de cafeeiro (Coffea arabica L.) e seringueira (Hevea brasiliensis Muell. Arg.) em diferentes sistemas de cultivo: monocultivo e consórcio(Editora UFLA, 2004-03) Oliveira, Cláudio Roberto Meira de; Soares, Angela Maria; Oliveira, Luiz Edson Mota de; Castro, Evaristo Mauro de; Barbosa, João Paulo R. Alves DelfinoObjetivou-se avaliar neste trabalho as influências do sistema de cultivo em plantas de seringueiras (Hevea brasiliensis Muell Arg.) e de cafeeiros (Coffea arabica L.) na fase de estabelecimento do plantio. Foram avaliadas características de cresci- mento das plantas de seringueira e a estrutura foliar de cafeeiros e seringueiras em condições de monocultivo e dois tipos de consórcio: renque e margem. Pela análise dos resultados obtidos evidenciou-se que o sistema de cultivo não influenciou o padrão de crescimento das plantas de seringueira. Em geral, o sistema de cultivo não influenciou a anatomia foliar dos cafeeiros nessa fase do cultivo.Item Influência de diferentes níveis de sombreamento no comportamento fisiológico de cultivares de café (Coffea arabica L.)(Editora UFLA, 2003-07) Freitas, Rupert Barros de; Oliviera, Luiz Edson Mota de; Delú Filho, Nelson; Soares, Angela MariaRealizou-se este trabalho com o objetivo de verificar o comportamento das cultivares de café Acaiá MG 474/19, Catuaí MG 99, Icatu Amarelo MG 3282 e Rubi MG 1192, com relação às características potencial hídrico, transpiração, temperatura da superfície foliar, condutância estomática, fotossíntese, concentração interna de carbono e eficiência fotoquímica do PSII, quando submetidos a níveis de sombreamentos de 30%, 50%, 70% e a pleno sol. As avaliações foram realizadas no Setor de Fisiologia Vegetal em mudas dessas cultivares. O delineamento experimental utilizado foi o inteiramente casualizado, sendo distribuídos três vasos por cultivar em cada tratamento. O potencial hídrico foliar não variou nas plantas nos diferentes tratamentos. A fotossíntese, condutância estomática, transpiração, eficiência fotoquímica do PSII apresentaram variações significativas em função dos ní- veis de sombreamento.Item Estudo anatômico de cafeeiros enxertados(Editora UFLA, 2009-05) Dias, Fábio Pereira; Castro, Daniel Melo de; Mendes, Antônio Nazareno Guimarães; Vallone, Haroldo Silva; Carvalho, Alex Mendonça de; Carvalho, Gladyston RodriguesNeste trabalho, objetivou-se, avaliar as características anatômicas do caule de cafeeiros enxertados, auto-enxertados e pé- franco. Foram utilizadas as cultivares Catucaí Amarelo 2 SL e Topázio MG 1190 (Coffea arabica L.) e o porta-enxerto Apoatã IAC 2258 (C. canephora Pierre ex Froehn.). As seções anatômicas longitudinais e transversais foram realizadas aos 30, 60 e 90 dias após a enxertia. Os resultados não mostraram evidências de incompatibilidade de reconstituição e formação de tecidos entre as cultivares estudadas.Item Source-sink manipulations in Coffea arabica L. and its effect on growth of shoots and root system(Editora UFLA, 2011-09) Alves, José Donizeti; Paglis, Carlos Maurício; Livramento, Darlan Einstein do; Linhares, Suellen Sarah Drumond; Becker, Frederico Biagi; Mesquita, Alessandro CarlosThis paper investigated changes in growth and carbohydrate content of shoots and root systems in response to source-sink manipulation in field-grown coffee trees. The source-sink manipulations were carried out using manual de-fruiting. Two plots of trees were established: in one group, the fruit was left on the tree, while in the second group all fruits were removed manually. Similar results were obtained for coffee trees with and without fruit in terms of height, stem and skirt diameter and branch lengths. A biochemical evaluation of the roots showed that no differences were found between the levels of carbohydrates. In the leaves, levels of soluble sugars and reducing sugars were higher in plants with fruit. The starch concentration in leaves and roots did not vary between the plots. Root length density did not vary between plants with and without fruit in the 0 - 0.4 m soil layer. However, plants without fruit had a higher root length density than plants with a full fruit load. These results contrast with results published by others on source-sink relationships of coffee plants. The joint data analysis shows that young trees, with a moderate fruit load, and with good nutritional and health status, produce carbohydrates in sufficient quantities to maintain vegetative and reproductive growth, without harming root system growth.Item Anatomic and physiological modifications in seedlings of Coffea arabica cultivar Siriema under drought conditions(Editora UFLA, 2014-01) Melo, Emanuelle Ferreira; Fernandes-Brum, Christiane Noronha; Pereira, Fabrício José; Castro, Evaristo Mauro de; Chalfun-Júnior, AntonioDue to the weather changes prognostic for the coming years, the understanding of water deficit and physiological responses of plants to drought becomes an important requirement in order to develop technologies such as mechanisms to assist plants to cope with longer drought periods, which will be essential to maintenance of Brazilian and worldwide production. This study aimed to evaluate ecophysiological and anatomical aspects as well as the nitrate reductase activity in Siriema coffee seedlings subjected to four treatments: Daily irrigated, non-irrigated, re-irrigated 24 hours and re-irrigated 48 hours after different stress periods. Non-irrigation promoted a reduction in leaf water potential being accented from the ninth day of evaluation onwards. Re-irrigation promoted a partial recovery of the plant water potential. Non-irrigated plants showed an increase in stomatal resistance and reduction of transpiration and nitrate reductase activity. In the roots, there was a decrease in nitrate reductase activity under water stress. Leaf anatomical modifications were significant only for the adaxial surface epidermis and palisade parenchyma thickness, this latter characteristic being higher in control plants. Stomatal density and polar and equatorial diameter ratios showed the highest values in plants under water stress. In the roots, differences only in the cortex thickness being bigger in the non-irrigated treatment could be observed. Therefore, Siriema coffee plants under water stress show physiological, biochemical and anatomical modifications that contribute to the tolerance of this genotype to these conditions.