Navegando por Autor "Ramalho, José D. Cochicho"

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Aspects of nitrogen metabolism in coffee plants
(Brazilian Journal of Plant Physiology, 2006-06) Carelli, Maria Luiza Carvalho; Fahl, Joel Irineu; Ramalho, José D. Cochicho
Coffee plants are highly N-demanding plants. Despite the importance of N nutrition for the development, acclimation and yield of coffee plants, there are few reports concerning N metabolism in this species. In this review, our intention is to summarize the information available in the literature and to point out the influence of environmental conditions on N assimilation, as well as comment and discuss some apparently contradictory results and raise and enlighten queries about N assimilation in coffee plants.
Efeitos de baixas temperaturas positivas na fotossíntese e estabilidade membranar em 5 genótipos de Coffea sp.
(2000) Ramalho, José D. Cochicho; Quartin, V. L.; Campos, Paula S.; Carelli, Maria Luiza Carvalho; Fahl, Joel Irineu; Nunes, M. A.; Consórcio Brasileiro de Pesquisa e Desenvolvimento do Café
Indícios de diferenças na sensibilidade ao frio por parte de cafeeiros, observadas no campo durante as severas geadas de 1994 no Brasil, serviram de ponto de partida para o presente trabalho. Estudaram-se diversos parâmetros, em nível foliar, em plantas de 5 genótipos de Coffea (C. canephora cv. Apoatã; C. arabica cv. Catuaí; C. dewevrei; Icatu, um híbrido de C. canephora X C.arabica; Piatã, um híbrido de C. dewevrei X C. arabica), às quais se aplicou um esquema de aclimatação ao frio e de submissão a baixas temperaturas positivas ("chilling"), acompanhando-se também a sua recuperação após o tratamento de frio. Os resultados dos parâmetros fotossintéticos e de estabilidade membranar mostram diferenças de sensibilidade aos tratamentos de frio, que apontam para uma tolerância contrastante entre C. dewevrei (mais sensível) e Icatu (mais tolerante). Essas diferenças observaram-se não só durante o período de sujeição das plantas ao tratamento de "chilling" (3 noites a 4 ºC), mas também em frio moderado (15/10 ºC) e na recuperação do estresse. A análise sumária de crescimento indicia maior vigor de Piatã, reflectido em maior crescimento e acumulação de biomassa, mas que não teve correspondência positiva nos parâmetros fisiológicos estudados quando as plantas foram submetidas aos tratamentos de "chilling".
Impacts of drought and temperature stress on coffee physiology and production: a review
(Brazilian Journal of Plant Physiology, 2006-06) DaMatta, Fábio M.; Ramalho, José D. Cochicho
Overall, drought and unfavourable temperatures are the major climatic limitations for coffee production. These limitations are expected to become increasingly important in several coffee growing regions due to the recognized changes in global climate, and also because coffee cultivation has spread towards marginal lands, where water shortage and unfavourable temperatures constitute major constraints to coffee yield. In this review, we examine the impacts of such limitations on the physiology, and consequently on the production of mainly Coffea arabica and C. canephora, which account for about 99 % of the world coffee bean production. The first section deals with climatic factors and the coffee plant’s requirements. The importance of controlling oxidative stress for the expression of drought and cold tolerance abilities is emphasized in the second section. In the third section, we examine the impacts of drought on cell-water relations, stomatal behaviour and water use, photosynthesis and crop yield, carbon and nitrogen metabolism, root growth and characteristics, and on drought tolerance. In the fourth section, the impacts of low positive and high temperatures on coffee physiology are discussed; some insights about effects of negative temperatures are also presented. Finally, the last section deals with shading in harsh environments as a mean of buffering climatic fluctuations, as well as of increasing environmental sustainability in coffee exploitation.