Bem vindo à Biblioteca do Café
O SBICafé é um repositório temático da produção científica das instituições que integram o Consórcio Brasileiro de Pesquisa e Desenvolvimento do Café (Consórcio Pesquisa Café). Seu objetivo é unificar e facilitar o acesso à produção científica das instituições consorciadas, no que se refere a temas relacionados ao agronegócio do café, aumentando assim a visibilidade, o uso e o impacto dos resultados das pesquisas depositadas, no intuito de fortalecer os projetos desenvolvidos em torno do Programa Nacional de Pesquisa e Desenvolvimento do Café (PNP D/Café), aumentando sua produtividade, progresso e recompensas.
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Períodos de interferência de Commelina benghalensis na cultura do café recém-plantada
(Sociedade Brasileira da Ciência das Plantas Daninhas, 2005-09) Dias, T. C. S.; Alves, P. L. C. A.; Lemes, L. N.
A presente pesquisa teve por objetivo avaliar os períodos de interferência de Commelina benghalensis sobre o crescimento inicial de mudas de Coffea arabica, sob condições de inverno e verão. Para isso, mudas de café e, posteriormente, de trapoeraba foram transplantadas para caixas de cimento-amianto com capacidade de 70 L, utilizando solo como substrato. Os períodos de convivência ou controle foram de 0-15, 0-30, 0-45, 0-60, 075 e 0-90 dias após o plantio do cafeeiro, totalizando 12 tratamentos, dispostos em blocos casualizados, em quatro repetições. Ao término de cada período, avaliaram-se algumas características de crescimento das plantas. As características do cafeeiro mais afetadas pela trapoeraba foram a área foliar e a biomassa seca de folhas das mudas de café, sendo essas as únicas características que apresentaram reduções significativas no verão. No inverno, o número de folhas e a biomassa seca do caule também tiveram reduções significativas. Os períodos críticos de prevenção da interferência foram de 15 a 88 e 22 a 38 dias após o plantio das mudas de café, para condições de inverno e verão, respectivamente.
Induction and differentiation of reproductive buds in Coffea arabica L.
(Brazilian Journal of Plant Physiology, 2005-06) Majerowicz, Nidia; Söndahl, Maro R.
The induction and differentiation phases of reproductive buds of Coffea arabica L. have not received much attention. In the present paper, axillary buds from five plagiotropic branches that developed in the same growing season without fruits (1st crop branches), and from green segments of five recently grown plagiotropic branches with fruits (2nd crop branches), were collected every two weeks during successive inductive months of the year. This study was carried out with adult arabica trees, Catuaí Vermelho cv. IAC 81, cultivated under normal farming conditions in the region of Campinas, SP, Brazil (22º54' Lat. S). Slides of longitudinal-axial sections of 10-12 mum thickness were mounted for the characterization and quantification of histological stages of bud differentiation. The results indicate that the regulatory signals controlling the phases of induction and differentiation of floral buds are distinct, and that there are differences in the response between branches with and without fruits. In the case of 1st crop branches (no fruits present), induction of floral buds took place in January and February, whereas floral bud differentiation was observed during the months of March and April. In 2nd crop branches (fruits present), the induction of floral buds was observed during any month of the year provided that they had already overcome their juvenile state (October-July, in this study). In these 2nd crop branches, the flower bud differentiation was only observed after harvesting all pre-existing fruits of each branch (after May, in this study), which suggests that floral bud differentiation in Arabica coffee is influenced by the source-sink relationship, i.e. by the presence of developing fruits within each plagiotropic branch.
Ethylene production and acc oxidase gene expression during fruit ripening of Coffea arabica L.
(Brazilian Journal of Plant Physiology, 2005-09) Pereira, Luiz Filipe Protasio; Galvão, Rafaelo M.; Kobayashi, Adilson K.; Cação, Sandra Maria B.; Vieira, Luiz Gonzaga Esteves
The phytohormone ethylene is involved in several physiological and developmental processes in higher plants, including ripening of fruits, abscission of organs and tissues, senescence, wound response as well as in other abiotic stresses. The enzyme 1-aminocyclopropane-1-carboxylate oxidase (ACO) catalyzes the last step of ethylene biosynthesis. The production of ethylene and the expression of a Coffea arabica ACO gene during the last stages of fruit maturation were investigated. A rapid increase of ethylene production at the green-yellow stage of fruit ripening, after the end of endosperm formation, and a decrease of ethylene production at the cherry stage indicates a climacteric phase during ripening. An ACC oxidase (Ca-ACO) from coffee fruit cDNA was cloned and characterized using primers previously reported. The cDNA is homologous to previously described ACC oxidase cDNA in Coffea. The nucleotide and amino acid deduced sequences of the clone showed high homology with ACO from climacteric fruits. Northern blots were performed to determine the Ca-ACO transcription pattern from different tissues and from fruits at different ripening stages. Coffee fruits at an early ripening stage (green) showed the lowest level of Ca-ACO transcript accumulation. The transcript levels of Ca-ACO did not change significantly during the later stages, suggesting the presence of post- transcriptional control mechanisms. These results, taken together, strongly suggest a climacteric nature of coffee fruit ripening.
Coffee leaf miner resistance
(Brazilian Journal of Plant Physiology, 2006-06) Guerreiro Filho, Oliveiro
The coffee leaf miner, Leucoptera coffeella, is a common pest of coffee plantations in Brazil. Though it is effective, chemical control substantially increases the cost of production and constitutes a significant risk for the environment. Resistant coffee cultivars have been and continue being developed through classic and molecular selection techniques. Basic knowledge about the biology of this insect, the damage it causes to the plants, the identification of sources of resistance, the development of efficient selection methods and knowledge about the genetics of resistance have contributed to the efficiency of the ongoing genetic improvement programs. Recently, coffee genomics studies have also promoted an improvement in the efficiency of the development of cultivars resistant to this insect. We present a short review of each of these aspects of the search for resistance.
Metabolism of alkaloids in coffee plants
(Brazilian Journal of Plant Physiology, 2006-06) Ashihara, Hiroshi
Coffee beans contain two types of alkaloids, caffeine and trigonelline, as major components. This review describes the distribution and metabolism of these compounds. Caffeine is synthesised from xanthosine derived from purine nucleotides. The major biosynthetic route is xanthosine -> 7-methylxanthosine -> 7-methylxanthine -> theobromine -> caffeine. Degradation activity of caffeine in coffee plants is very low, but catabolism of theophylline is always present. Theophylline is converted to xanthine, and then enters the conventional purine degradation pathway. A recent development in caffeine research is the successful cloning of genes of N-methyltransferases and characterization of recombinant proteins of these genes. Possible biotechnological applications are discussed briefly. Trigonelline (N-methylnicotinic acid) is synthesised from nicotinic acid derived from nicotinamide adenine nucleotides. Nicotinate N-methyltransferase (trigonelline synthase) activity was detected in coffee plants, but purification of this enzyme or cloning of the genes of this N-methyltransferase has not yet been reported. The degradation activity of trigonelline in coffee plants is extremely low.
