Revista Brasileira de Sementes

URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/13761

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20122

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Assunto: search.filters.subject.germination

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    Physiological quality of coffee seeds produced under different levels of solar radiation and maturation stages
    (Associação Brasileira de Tecnologia de Sementes, 2012-10-01) Baliza, Danielle Pereira; Caixeta, Franciele; Von Pinho, Édila Vilela de Resende; Cunha, Rodrigo Luz da; Martins, Denize Carvalho; Rosa, Sttela Dellyzete Veiga Franco da
    In Brazil, although the coffee plantations are predominantly grown under full sunlight, the use of agroforestry systems can lead to socioeconomic advantages, thus providing a favorable environment to the crop by promoting its sustainability as well as environmental preservation. However, there is a lack of information on physiological quality of the coffee seeds produced under different levels of solar radiation. Within this context, the objective of this study was to evaluate the influence of different levels of solar radiation and maturation stages on the physiological quality of coffee (Coffea arabica L.) seeds, cv. Acaiá Cerrado MG-1474. Three levels of solar radiation (plants grown under full sunlight; under plastic screens of 35% shading; and under plastic screens of 50% shading) and three maturation stages (cherry, greenish-yellow and green) were assessed. Physiological quality of seeds was assessed by using germination test, first count of germination, abnormal seedlings, dead seeds, and seedlings with open cotyledonary leaves. Electrophoretic analysis of isoenzymes catalase, esterase, superoxide dismutase and peroxidase was also performed. With the evolution of development the coffee seeds presents increases on physiological quality, and at its beginning the seeds show improvements on quality with the reduction of solar radiation.
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    Test of exudates color hues for evaluating the physiological potential of coffee (Coffea arabica L.) seeds
    (Associação Brasileira de Tecnologia de Sementes, 2012-06-27) Hilst, Paulo Cesar; Dias, Denise Cunha Fernandes dos Santos; Alvarenga, Eveline Mantovani; Souza, Bruna Luiza de
    Coffee seeds have slow and irregular germination, losing fast their viability during storage, and the standard germination test of these seeds requires at least 30 days. Besides, the results may not reflect the actual physiological quality of these seeds. The objective of this work was to develop a fast and practical test for evaluating the viability of coffee seeds, which is based on the interpretation of different color hues of exudates from seeds. Coffee seeds of the cultivar Catuai 44 from six lots were submitted to germination, accelerated aging, and electrical conductivity tests. In the exudates color hue test, coffee seeds without the parchment and the silvery pellicle (four replications of 10 seeds each) were distributed on top of paper towels moistened and then maintained into a germinator, at 25 ºC for 24, 48, 72, 96, and 120 h. Three classes of color hues were established: colorless, light color hue, and dark color hue, assigning the values of 0, 1, and 3, for each class, respectively. The proposed exudates color hue test can be recommended for the fast assessment of viability for coffee seeds. The most promising results were obtained for seeds with 12% moisture content, after imbibition periods of 72, 96, and 120 h; and with 30% moisture content, after imbibition periods of 72 and 120 h.