Ciência e Agrotecnologia

URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/9885

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Magnetic field in coffee seed germination
(Editora UFLA, 2020-07-13) Braga Júnior, Roberto Alves; Azevedo, Roberto Luiz de; Guimarães, Renato Mendes; Reis, Leandro Vilela
The effective production of coffee seedlings faces many challenges, including seed germination. Therefore, a reduced seed germination period can be one of the most relevant contributions to enhance the testing and production of robust seedlings. The objective of this research was to evaluate the effects of a constant magnetic field on the germination of coffee seeds (Coffea arabica L.). The analyses were performed using a biospeckle laser (BSL) in conjunction with traditional seed viability tests. The coffee seeds were subjected to magnetic fields of constant intensity at values of 10 mT and 28 mT for a time interval of 6 days during their germination process. The embryo region was illuminated, and the images obtained by the BSL were processed. The activity levels of this region were compared with the data obtained using traditional physiological seed analysis. In addition to the results of BSL activity, the results of the seed analysis, such as isoenzymatic catalase (CAT), esterase (EST), superoxide dismutase (SOD), malate dehydrogenase (MDH) and endo-β-mananase, membrane integrity, germination, germination speed index (GSI), emergence speed index (ESI), and radicular protrusion levels, were obtained during the germination process. In conclusion, magnetic pretreatment with both intensities during the first six days of germination improved the permeability of the cellular membranes and advanced the activation of the antioxidant system, thus promoting faster and more uniform seed germination.
Seedling production of Coffea arabica from different cultivars in a modified hydroponic system and nursery using different containers
(Editora UFLA, 2021-11-22) Lima, Amador Eduardo de; Guimarães, Rubens José; Cunha, Samuel Henrique Braga da; Castro, Elisa de Melo; Carvalho, Alex Mendonça de; Faria, Mauro Magalhães Leite
The development of modified hydroponic cultivation has aroused interest and its use has enabled advantages in several crops, but studies for coffee are still scarce. Thus, the objective of this research was to evaluate seedling production of three Coffea arabica cultivars (Mundo Novo IAC-376-4, Catuaí IAC-62 Amarelo and MGS Paraíso 2), in a modified hydroponic system, and to compare it with the nursery production system, using plastic polyethylene tubettes and bags. Coffee seedlings in the development phase with cotyledon leaves, were cultivated in both cultivation systems. At 90 days after the implementation of the experiment, the seedlings were analyzed for growth (height, stem diameter, total number, leaf area, root area, root and shoot dry matter weight), and physiological characteristics (chlorophyll content and stomatal conductance). For the statistical analysis, a completely randomized design (CRD) was used in a factorial scheme 3 (cultivars) x 2 (containers) x 2 (cultivation systems), with four replications of ten plants per plot. The innovative production system of coffee seedlings in modified hydroponics, in combination with the use of polyethylene bags, provided greater growth of coffee seedlings with better physiological characteristics. Among the cultivars tested, MGS Paraíso 2 stood out with higher seedling growth (number of leaves, stem diameter and root and shoot dry matter weight).
Physiological, biochemical, and ultrastructural aspects of Coffea arabica L. seeds under different cryopreservation protocols
(Editora UFLA, 2021) Figueiredo, Madeleine Alves de; Rosa, Sttela Dellyzete Veiga Franco da; Ricaldoni, Marcela Andreotti; Pereira, Cristiane Carvalho; Coelho, Stefânia Vilas Boas; Silva, Luciano Coutinho
Cryopreservation is a technique that may potentially conserve the germplasm of species of the Coffea genus for an indeterminate time. The aim of this study was to evaluate the physiological, biochemical and ultrastructural characteristics of cryopreserved seeds of Coffea arabica L., cultivar Catucaí amarelo IAC 62, which was subjected to different protocols regarding dehydration, precooling, cooling, rewarming and cathode water use. According to each protocol, the seeds were subjected to fast or slow drying to moisture contents of 17 or 20% (wet basis), cooled in different ways, and then immersed in liquid nitrogen for 24 hours. Different rewarming times in a water bath were also used. Physiological, biochemical and ultrastructural analyses were performed on the seeds after the cryopreservation steps. Moisture content at a 17% wb is the key factor for the cryopreservation of Coffea arabica L. seeds, which have better physiological quality and better preserved cell structures. Precooling of coffee seeds before immersion in liquid nitrogen does not provide advantages compared to direct immersion. The rewarming times tested (2, 4, and 6 minutes) and cathode water use did not cause changes in the physiological and biochemical quality or in the cell structures of Coffea arabica L. cryopreserved seeds. The pattern of cell structure observed in all seeds indicates that the damage from cryopreservation is less drastic in the cells of the embryos than in those of the endosperm, with the latter less tolerant to the stresses of dehydration, precooling, and rewarming.
Magnetic field in coffee seed germination
(Editora UFLA, 2020) Braga Júnior, Roberto Alves; Azevedo, Roberto Luiz de; Guimarães, Renato Mendes; Reis, Leandro Vilela
The effective production of coffee seedlings faces many challenges, including seed germination. Therefore, a reduced seed germination period can be one of the most relevant contributions to enhance the testing and production of robust seedlings. The objective of this research was to evaluate the effects of a constant magnetic field on the germination of coffee seeds (Coffea arabica L.). The analyses were performed using a biospeckle laser (BSL) in conjunction with traditional seed viability tests. The coffee seeds were subjected to magnetic fields of constant intensity at values of 10 mT and 28 mT for a time interval of 6 days during their germination process. The embryo region was illuminated, and the images obtained by the BSL were processed. The activity levels of this region were compared with the data obtained using traditional physiological seed analysis. In addition to the results of BSL activity, the results of the seed analysis, such as isoenzymatic catalase (CAT), esterase (EST), superoxide dismutase (SOD), malate dehydrogenase (MDH) and endo-β-mananase, membrane integrity, germination, germination speed index (GSI), emergence speed index (ESI), and radicular protrusion levels, were obtained during the germination process. In conclusion, magnetic pretreatment with both intensities during the first six days of germination improved the permeability of the cellular membranes and advanced the activation of the antioxidant system, thus promoting faster and more uniform seed germination.
Roles of arbuscular mycorrhizal fungi on acclimatization of clones of Coffea arabica L. produced by somatic embryogenesis
(Editora UFLA, 2020) Fonseca, Arley José; Tassone, Guilherme Augusto Teixeira; Carneiro, Marco Aurélio Carbone; Carvalho, Gladyston Rodrigues; Carvalho, Carlos Henrique Siqueira; Botelho, Cesar Elias
The production of Coffea arabica L. clone seedlings through the somatic embryogenesis technique is one of the alternatives of greatest demand for coffee producers. However, clones can face difficulties related to acclimatization carried out under greenhouse conditions, which can increase the production costs. A tested alternative with promising results is inoculation with arbuscular mycorrhizal fungi (AMF) during the seedling acclimatization process. Thus, this study aimed to promote the improvement of the seedling production process through somatic embryogenesis associated with inoculation with AMF. For the production of the clones, seedlings were used in the phase when they presented four pairs of leaves (Clone 1 “Fruiting red Catucaí” and Clone 2 “Acauã”), using “somatic embryogenesis” bioreactors, followed by inoculation with Rhizophagus clarus, Gigaspora margarita and Acaulospora mellea, a mixture of R. clarus and G. margarita and a mixture of R. clarus, G. margarita and A. mellea. After six months, agronomic parameters, leaf nutrient contents and root mycorrhizal colonization were evaluated. The studied clones behaved differently when inoculated with AMFs. Clone 1 showed the best development in the greenhouse, which was determined by the agronomic parameters. Thus, Clone 1 is indicated for the production of vigorous seedlings when associated with inoculation with AMFs.
Crescimento vegetativo e produtividade de cafeeiros Conilon propagados por estacas em tubetes
(Editora UFLA, 2007-11) Amaral, José Augusto Teixeira do; Lopes, José Carlos; Amaral, José Francisco Teixeira do; Saraiva, Sérgio Henriques; Jesus Jr, Waldir Cintra de
Objetivou-se neste trabalho avaliar o crescimento vegetativo e a produtividade de cafeeiros conilon (Coffea canephora Pierre ex Froehner), oriundos de mudas produzidas por estacas plantadas inicialmente em tubetes plásticos de 50 cm 3 de capacidade. O experimento foi constituído de cinco tratamentos, que corresponderam aos tempos de permanência das estacas nos tubetes: 0; 15; 30; 45 e 60 dias. Transcorridos esses tempos as mudas foram, sucessivamente, transplantadas para sacos de polietileno, contendo mistura de terra, esterco de curral e adubo químico, enviveiradas em um viveiro coberto com sombrite (50%), provido de micro aspersão automática. As mudas permaneceram no viveiro com micro aspersão automática por 150 dias, quando então foram transferidas para o viveiro de aclimatação, onde ficaram por mais 30 dias. Após esse período, em setembro de 1999, as mudas foram plantadas em condições de campo, na área experimental do CCA-UFES, em Alegre, Sul do Estado do Espírito Santo. Foram feitas as seguintes medições: crescimento de ramos ortotrópicos e plagiotrópicos no segundo ano após o plantio e as quatro primeiras colheitas. A produção inicial de mudas de café conilon em tubetes não afetou o crescimento vegetativo, tampouco a produção de frutos.
Cryopreservation in Coffea canephora Pierre seeds: slow and fast cooling
(Editora UFLA, 2018-11) Coelho, Stefânia Vilas Boas; Rosa, Sttela Dellyzete Veiga Franco da; Fantazzini, Tatiana Botelho; Baute, Júlia Lima; Silva, Luciano Coutinho
Coffee is one of the main agricultural commodities in the country, and it is important to conservation of plant material for breeding programs. Cryopreservation is a promising alternative for preserving in the long-term the germplasm of species considered recalcitrant. However, studies should be performed to achieve maximum survival of seedlings after immersion in liquid nitrogen. The objective of this work was to find a cryopreservation protocol for storing seeds of Coffea canephora, studying two methods of cryopreservation, slow and fast cooling. Seeds were subjected to drying in silica gel up to the water content of 0.25 g g -1 . In the first experiment, dried seeds were subjected to treatments of slow cooling at speeds of -1 oC min -1 ,-3 oC min -1 and -5 oC min -1 until the end temperatures of -40 oC, -50 oC and -60 oC, by means of a bio freezer and subsequently immersed in liquid nitrogen. In the second experiment, the best result was selected of the first experiment and compared with the rapid cooling, in which dried seeds, with 0.25 g g -1 of water content, were immersed directly into liquid nitrogen. Physiological and biochemical alterations occurring in the seeds after cryopreservation were evaluated. Coffea canephora seeds respond better to cryopreservation by rapid cooling, when compared to slow cooling. Drying, one of the cryopreservation steps does not affect the viability of Coffea canephora Pierre seeds, when these seeds are dried to 0.25 g g -1 of water content. Catalase and esterase enzymes are good biochemical markers for cryopreserved coffee seeds and their activity is greater in larger seed physiological quality.
Avaliações anatômicas foliares em mudas de café 'Catuaí' e 'Siriema' submetidas ao estresse hídrico
(Editora UFLA, 2008-11) Grisi, Fernanda Almeida; Alves, osé Donizeti; Castro, Evaristo Mauro de; Oliveira, Cynthia de; Biagiotti, Gabriel; Melo, Lucas Amaral de
Objetivou-se verificar a existência de características de resistência à seca em mudas da cultivar Siriema em relação à cv. Catuaí. O experimento foi conduzido em viveiro com sombrite e plástico na área experimental do DBI/UFLA, MG. Foram utilizadas mudas de cafeeiros com seis meses de idade, seis a oito pares de folhas, provenientes do viveiro da Fundação Procafé, em Varginha, MG. Antes da indução dos tratamentos, as mudas foram irrigadas diariamente; depois, os tratamentos foram estabelecidos: um grupo continuava irrigado e outro grupo submetido à suspensão de rega. O período experimental foi de 10 dias e a unidade experimental foi composta por uma planta, sendo cinco repetições, dispostas em Delineamento Inteiramente Casualizado (DIC). Para a epiderme adaxial e abaxial, índice estomático e razão PP/LF não houve diferenças significativas em nenhuma situação estudada. Para o parênquima esponjoso no tratamento irrigado, o ‘Siriema’ apresentou maior espessura em relação à cv. Catuaí, enquanto que o parênquima paliçádico não apresentou diferenças. O limbo foliar do ‘Siriema’ foi mais espesso que o da cv. Catuaí, independentemente do tratamento. Os diâmetros polar e equatorial dos estômatos foram maiores no tratamento não irrigado para o ‘Siriema’. Para a relação DP/DE e densidade estomática, o ‘Siriema’ não irrigado apresentou-se maior em relação à cv. Catuaí não irrigada. Nas condições deste experimento, os diâmetros polar e equatorial dos estômatos, relação DP/DE e densidade estomática permitiram discriminar satisfatoriamente os dois cafés estudados em termos de tolerância diferencial à seca, a favor do material ‘Siriema’.
Teste de condutividade elétrica individual na avaliação da qualidade fisiológica de sementes de café (Coffea arabica L.)
(Editora UFLA, 2006-01) Costa, Paula de Souza Cabral; Carvalho, Maria Laene Moreira de
O teste de condutividade elétrica é usado para medir os exsudatos das sementes, que certamente refletem a integridade do sistema de membranas. O teste é rápido e de operação simples, mas a metodologia necessita ser testada para cada espécie individualmente para obter uma melhor precisão e exatidão dos resultados. Este trabalho foi conduzido visando determinar o ponto de partição na realização do teste de condutividade elétrica em sementes de café. Dez lotes de sementes de Coffea arabica sem pergaminho, cultivar Acaiá foram usados nesse estudo. Para a avaliação do ponto de partição as sementes foram embebidas por 96 horas e submetidas ao teste de germinação, correlacionando os valores de condutividade observados com os valores obtidos no teste de germinação. O ponto de partição é de 120,5μS.cm -1 , considerando 70% de germinação.
Efeito da celulase sobre a decomposição do pergaminho e sua influência na velocidade e porcentagem de germinação de sementes de cafeeiro
(Editora UFLA, 2005-11) Sales, Juliana de Fátima; Alvarenga, Amauri Alves de; Oliveira, João Almir de; Nogueira, Francisco Dias; Silva, Fabiano Guimarães; Veiga, André Dely
Com este trabalho, objetivou-se verificar a ação da celulase sobre a decomposição do pergaminho das sementes de cafeeiro. Foram implantados dois experimentos, sendo o primeiro, realizado em condições in vitro. Constituído por três ensaios para avaliar os efeitos das concentrações da enzima, do substrato e sacarificação enzimática do pergaminho. O segundo, foi realizado em condições in vivo, com imersão das sementes de cafeeiro em solução de celulase na concentração de 1,6 g.L -1 em tampão citrato de potássio 0,05 mol.L -1 . Observou-se que a quantidade de açúcar liberado in vitro foi diretamente relacionada com a concentração de enzima, e que houve aumento expressivo e linear na quantidade de açúcares redutores liberados nas duas concentrações (1,6 e 3,2 g.L -1 ) à medida que se aumentou o tempo de incubação das amostras de substrato (pergaminho) com a solução enzimática. Foi verificado também, nos testes de germinação e emergência, que as sementes sem pergaminho apresentam maiores índices de velocidade e porcentagem de germinação e emergência comparado às sementes com pergaminho e que a celulase nesta concentração ainda não proporciona aumento na velocidade de germinação das sementes, necessitando-se de concentrações mais elevadas.

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