Periódicos
URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3352
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Resultados da Pesquisa
Item Effects of shade trees spatial distribution and species on photosynthetic rate of coffee trees(Editora UFLA, 2019-07) Silva Neto, Francisco José da; Bonfanti, Leila; Gazaffi, Rodrigo; Fontanetti, AnastáciaThe use of shade trees in coffee fields have been motivated by climatic changes. However, microclimatic conditions in shaded coffee fields differ due to shade tree spatial distribution and species, altering physiological responses of coffee trees. This study aimed to evaluate the effects of shade tree spatial distribution and species on coffee trees photosynthetic rate in two growth seasons, of high (HSD) and low (LSD) sink demand. The experimental design consisted of randomized blocks with three replicates in split-split-plots. Plots were the shade tree species: Anadenanthera falcata, Cassia grandis and Peltophorum dubium. Split plot was formed by five distances between coffee trees and shade tree trunks: coffee trees on planting row of shade trees, distancing one (D1L) and five (D5L) meters from shade trees trunk; coffee trees on inter-rows of shade trees, parallel to D1L and D5L (D1E and D5E); coffee trees distancing 77 meters from shade tree trunks, in a full-sun field (PS). The split-split-plots correspond to coffee tree canopy exposure to the sun: branches facing North or South. Shade trees canopy density and occupation was evaluated with a convex densiometer. Photosynthetic rate (P n )and photosynthetic active radiation (PAR) were measured with an Infrared Gas Analyzer (IRGA) on two time-frames, between 7.00 and 9.00 solar hours and between 11.00 and 13.00. Shade tree canopy density and occupation was not homogenous during the change of seasons and shift due to spatial distribution, which also changes PAR levels. Shade trees reduce PAR to more suitable values for coffee tree exploitation, especially on D1L and D5L. During HSD, shading did not affect P n , which was greater in branches facing North. Yet, in LSD, between 11.00 and 13.00, coffee trees shaded with A. falcata showed greater P n than at PS. Coffee trees shaded with C. grandis at D5L and D1E had greater values of P n than PS.Item Sucrose in detoxification of coffee plants whit glyphosate drift(Editora UFLA, 2019-01) Alecrim, Ademilson de Oliveira; Guimarães, Rubens José; Castanheira, Dalyse Toledo; Rezende, Tiago Teruel; Carvalho, Milene Alves de Figueiredo; Voltolini, Giovani BeluttiThe weed control in coffee plants has great importance, as they compete for light, water and nutrients. The chemical control is the most used, emphasizing the glyphosate, however, when applied, drift can occur and consequently cause injuries to coffee. Many farmers use the sucrose application with the objective to reverse the damage caused by the herbicide drift, even without scientific basis to justify such action. The objective of this study was to evaluate the effect of the sucrose application on the detoxification of coffee plants in the implantation phase with glyphosate drift. The experiment was carried out in a greenhouse, using a randomized block design, arranged in a 3 x 3 factorial scheme with 2 additional treatments, using 3 sucrose doses (2, 4 and 8%) with 3 application times (1, 24 and 168 hours after intoxication with 10% of the commercial glyphosate dose) with an additional one in which the plants were not intoxicated and not treated with sucrose and another only with plants intoxicated by glyphosate. After 75 days performing the experiment, growth, physiological and anatomical characteristics were evaluated. The application of sucrose in the reversal of intoxication of growth variables (height, leaf area number of leaves, shoot dry weight and dry weight of the root system) was not efficient. The objective of this study was to evaluate the effect of the sucrose application on the detoxification of coffee plants in the implantation phase with glyphosate drift. For the physiological variables the application of 2% sucrose, one hour after glyphosate intoxication was the most efficient treatment.Item Desenvolvimento de gemas florais, florada, fotossíntese e produtividade de cafeeiros em condições de sombreamento(Empresa Brasileira de Pesquisa Agropecuária - Embrapa, 2008-04) Morais, Heverly; Marur, Celso Jamil; Caramori, Paulo Henrique; Koguishi, Mirian Sei; Gomes, José Carlos; Ribeiro, Ana Maria de ArrudaO objetivo deste trabalho foi avaliar a influência do sombreamento, durante o período de desenvolvimento floral, sobre as gemas florais, florada, fotossíntese e produtividade de cafeeiros. Cafeeiros adultos IAPAR 59 cultivados em Londrina, PR, foram sombreados em diferentes épocas, com malhas de sombrite com 50% de porosidade, e comparados com cafeeiros cultivados a pleno sol. As coberturas foram colocadas sobre as plantas em intervalos mensais, de abril a agosto, e retiradas no início de outubro. A densidade e o período de sombreamento não tiveram influência sobre a quantidade de nós, em cada estádio de desenvolvimento da gema floral, época e intensidade da florada, fotossíntese e produtividade dos cafeeiros, o que indica que a interceptação de até 50% da radiação, incidente no período de abril a agosto, época de desenvolvimento floral, não afeta o potencial produtivo desta cultura.Item Potencial de utilização de características anatômicas e fisiológicas na seleção de progênies de cafeeiro(Editora UFLA, 2016-07) Castanheira, Dalyse Toledo; Rezende, Tiago Teruel; Baliza, Danielle Pereira; Guedes, Janine Magalhães; Carvalho, Samuel Pereira; Guimarães, Rubens José; Viana, Mariana Thereza RodriguesObjetivou-se avaliar o potencial do uso de características anatômicas e fisiológicas, na seleção de progênies de cafeeiro tolerantes ao estresse hídrico. Para as avaliações anatômicas e fisiológicas foram amostradas vinte progênies oriundas de três tipos de grupos de procedências, da população do experimento instalado na UFLA. O delineamento foi inteiramente casualizado, com dois períodos de avaliação. As progênies estudadas apresentam variabilidade genética, tendo sido verificada divergência entre elas. Em geral, a variância genética das progênies é maior no período de seca, indicando que há maior variabilidade entre as progênies, nesse período. Características anatômicas e fisiológicas mostraram-se eficientes como uma tecnologia, para auxiliar a seleção de progênies de cafeeiro.