Examinando por Autor "Sterling Cuéllar, Armando"
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- ÍtemAnálisis del intercambio gaseoso y fluorescencia de la clorofila a de Hevea brasiliensis en respuesta a la infección por Microcyclus ulei en condiciones controladas de infecciónSterling Cuéllar, Armando; Romero Ospina, Manuel FranciscoThe main disease of rubber tree cultivation in Latin America, South American leaf blight (SALB), is caused by the fungus Microcyclus ulei. Most studies have focused on the mechanisms related with the resistance to the pathogen, so that physiological aspects involved in the infection is still unknown. This study aimed to determine the changes in parameters of gas exchange and chlorophyll a fluorescence of two clones of H. brasiliensis to the infection produced by M. ulei under conditions of controlled inoculation with use of general linear models with analysis of variance and measures repeated over time, correlation analysis and principal components. The results showed that the effect of the photosynthesis was proportional to the temporal progress and to the intensity of the disease symptoms. In this regard, the maximum significant reduction (p <0.05) in photosynthetic rates of the clone FX 3864 (susceptible) (88.3%) and of the FX 4098 (moderately resistant) (45.2%) were observed at 8 days after inoculation in leaflets B of 18 days old. Likewise, a significant difference was found in the ability to capture, use and dissipate light energy by part of the photosystem II between the two clones, which was evidenced in the minor photosynthesis of the susceptible clone. In general, the SALB was mainly correlated with the variables A, E, gs, Fv/Fm and NPQ, and was mainly associated with the FX 3864 rubber tree clone that was the most affected physiologically.