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Item Initial stages of infectious process of Pseudomonas syringae pv. garcae in coffee leaves(Editora UFLA, 2019-07) Souza, José Otávio Gusmão de; Pozza, Edson Ampélio; Belan, Leônidas Leoni; Freitas, Marcelo Loran de Oliveira; Oliveira, Júlia MarquesBacterial blight of coffee (Pseudomonas syringae pv. garcae) (PSG) has been causing damage and losses to coffee growing. However, initial stages of the infectious process should be described in order to understand the relationship cycle and to propose efficient management strategies. This study described the initial stages of infectious process of the PSG in coffee leaves over time. The bacterial penetration sites studied were stomata, leaf margins, and wounds. Coffee seedlings received 50μL inoculum suspension at marked points on the abaxial face and leaf margins, and around wounds. By 30 minutes, 1, 3, 6, and 12 hours after inoculation, leaf disks collected at inoculated points were analyzed with scanning electron microscopy. One hour after inoculation, bacterial groups could be seen as result of cell multiplication. Subsequently, the number of grouped bacteria increased proportionally over time. A growing population concentration was found near stomata, wounds, epidermal appendages, and wax layer on leaf margins and leaf tip. From these places bacteria were positioned in their long axis starting from structures, thus created a population gradient and displacement flow toward penetration sites. Initial stages of infectious process occurred in all penetration sites, thus it was not possible to determine a preferred pathway.Item Coffee leaf and stem anatomy under boron deficiency(Sociedade Brasileira de Ciência do Solo, 2007-05) Rosolem, Ciro Antonio; Leite, Vagner MaximinoBoron deficiency in coffee is widely spread in Brazilian plantations, but responses to B fertilizer have been erratic, depending on the year, form and time of application and B source. A better understanding of the effects of B on plant physiology and anatomy is important to establish a rational fertilization program since B translocation within the plant may be affected by plant anatomy. In this experiment, coffee plantlets of two varieties were grown in nutrient solutions with B levels of 0.0 (deficient), 5.0 μM (adequate) and 25.0 μM (high). At the first symptoms of deficiency, leaves were evaluated, the cell walls separated and assessed for B and Ca concentrations. Scanning electron micrographs were taken of cuts of young leaves and branch tips. The response of both coffee varieties to B was similar and toxicity symptoms were not observed. Boron concentrations in the cell walls increased with B solution while Ca concentrations were unaffected. The Ca/B ratio decreased with the increase of B in the nutrient solution. In deficiency of B, vascular tissues were disorganized and xylem walls thinner. B- deficient leaves had fewer and deformed stomata.Item Morfofisiologia foliar de cafeeiro sob diferentes níveis de restrição luminosa(Editora UFLA, 2010-09) César, Fábio Ricardo Coutinho Fontes; Matsumoto, Sylvana Naomi; Viana, Anselmo Eloy Silveira; Santos, Marcos Antônio Ferreira; Bonfim, Joice AndradeObjetivou-se, neste estudo, avaliar o comportamento morfofisiológico de variedades de cafeeiros arábica (Coffea arabica L.), em fase vegetativa inicial, cultivadas sob diferentes níveis de restrição luminosa artificial. O experimento foi conduzido no período de janeiro a junho do ano de 2007, no campo agropecuário da Universidade Estadual do Sudoeste da Bahia – UESB, em Vitória da Conquista, BA. Quatro ensaios foram definidos por níveis de 30, 50 e 70 % de restrição luminosa e a pleno sol, mantidas durante os primeiros 90 dias após emergência das plântulas. Para cada ensaio, o comportamento das variedades Catuaí (IAC 144), Catucaí 2SL, e Acauã foi avaliado, seguindo-se o delineamento de blocos casualizados, sendo avaliado o número de folhas, área foliar, teor relativo de água na folha, potencial hídrico foliar, teor foliar de prolina, número de células epidérmicas, número de estômatos e índice estomático. Os níveis de restrição luminosa afetaram o status hídrico dos cafeeiros, alterando a morfofisiologia dos mesmos. Para a variedade Catuaí, o maior teor de prolina foliar foi determinado em relação à variedade Catucaí. Com a elevação da restrição de luz ocorreu redução da densidade estomática, do número de células epidérmicas ordinárias e do índice estomático. Níveis de restrição de luz até 42,86 e 25,0 % favoreceram a elevação da área foliar e do número de folhas, respectivamente.