Examinando por Autor "Jarma Orozco, Alfredo de Jesús"
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Publicación Acceso abierto Fluorescencia de la clorofila y producción de biomasa de Stevia Rebaudiana Bertoni bajo atmósferas enriquecidas con co2, en Montería - Córdoba(Universidad de Córdoba, 2020) Espitia, Carlos Andres; Jarma Orozco, Alfredo de Jesús; Universidad de CórdobaEn Colombia el consumo de endulzantes con base en Stevia alcanza el 10% del mercado nacional, contra un 4% del mercado mundial (excluido Estados Unidos) y un 1% del mercado de Estados Unidos, de hecho, el conocimiento de la Stevia del consumidor colombiano es muy superior al promedio latinoamericano (excluido Brasil). Las plantas tienen la capacidad de captar el CO2 atmosférico, mediante procesos fotosintéticos metabolizarlo para la obtención de azúcares y otros compuestos que requieren para el normal desarrollo de su ciclo vital. En general, se puede concluir que las plantas, a través de la fotosíntesis, extraen el carbono de la atmósfera (en forma de CO2) y lo convierten en biomasa. El objetivo del presente trabajo fue determinar los efectos de atmosferas enriquecido con CO2 sobre la fisiología de dos clones experimentales de Stevia, bajo la técnica de nutrición carbónica usada en países con presencia de heladas o bajas temperaturas, siendo adaptado a condiciones tropicales, dicho estudio se llevó a cabo en las instalaciones de la Facultad de Ciencias Agrícolas de la Universidad de Córdoba; Se utilizó un diseño completamente al azar con un arreglo factorial desbalanceado (AxBxC+2), se analizó mediante un análisis de varianza permutacional, para mayor precisión. Se evaluaron variables de fluorescencia de la clorofila, masa seca y área foliar. Los resultados indicaron variaciones en la respuestas fisiológicas de las plantas de Stevia sometidas a altas concentraciones de CO2; la Fm´ presento un decaimiento en función del aumento en la concentración y el tiempo de inyección, 800 ppm 2 horas, 1200 ppm a 1 y 2 horas de inyección respectivamente, indicando el mismo comportamiento en la relación Fv´/Fm´ lo cual indica que generar un aumento en la concentración de CO2 por encima de 800 ppm genera una condición de estrés y por ende una disminución en la eficiencia fotosintética de la planta, a excepción de la concentración de 800 ppm la cual no afecto dichas variables.Publicación Acceso abierto Influencia del estrés salino en el crecimiento, intercambio gaseoso y pigmentos fotosintéticos de stevia (Stevia rebaudiana Bert.) bajo condiciones de invernadero en el caribe colombiano(2020-06-09) Castillejo Morales, Ángela María; Jarma Orozco, Alfredo de Jesús;The Stevia rebaudiana (Bertoni) species is an herbaceous plant, belonging to the genus Stevia Cav. characteristic of the American continent, member of the Eupatorieae tribe, family Asteraceae (Flores y Espinosa, 2018). It is a plant widely spread throughout the world since its leaves produce diterpene glycosides (steviosides and rebaudiosides), lowcalorie, non-toxic and high-potency sweeteners that can replace sucrose and other synthetic sweeteners, being 300 times sweeter than sucrose (A. Abbas Momtazi-Borojeni, S.-A. Esmaeili, E. Abdollahi, and AJC pd Sahebkar, 2017). The use of stevia has increased as a consequence of the awareness that the use of sucrose has raised about health. Beyond its value as a sweetener, stevia and its glycosides have therapeutic effects against various diseases such as cancer, diabetes mellitus, hypertension, inflammation, cystic fibrosis, obesity and dental caries. Studies have shown that the steviol glycosides found in stevia are not teratogenic, mutagenic, or carcinogenic and do not cause acute and subacute toxicity (A. Abbas Momtazi-Borojeni, S.-A. Esmaeili, E. Abdollahi, y A. Sahebkar, 2017). In addition to the benefits in human health, the cultivation of stevia implies the generation of jobs favoring the peasant and small producers labor force. In this sense, the University of Córdoba has developed adaptation and management studies in clones and promising stevia lines, which demonstrate the potential for planting in the Colombian Caribbean thanks to its agro-ecological diversity. However, the behavior of these promising new lines in the face of current and future changes, as a consequence of unsustainable anthropic activities such as the salinization of soils, is unknown. With the growth of the stevia market, the need to increase the production area has been generated, however, in the department of Córdoba, salinization problems arise, which affect crop yields, making it necessary To know the aspects applied to the productivity of stevia plants under saline stress conditions. Therefore, the purpose of this research work was to evaluate the response of growth parameters, gas exchange and photosynthetic pigments of Stevia rebaudiana Bert., To different concentrations of salts (0; 0.2; 0.5; 1, 2; 2.0 and 3.0 meq Na / 100g) in two genotypes (C19 and C04) under greenhouse conditions. Chapter II shows the study of the effect of five levels of salinization under greenhouse conditions on the production and distribution of stevia biomass. The relationship between growth and salt stress of the two stevia genotypes studied in the present investigation has a decreasing trend as NaCl doses are increased. The biomass located in the aerial organs is significantly affected with levels of 0.2 meq Na / 100g. Both genotypes showed a 8 tendency to increase in root biomass at the highest NaCl doses (2.0 and 3.0 meq Na / 100g), which could be considered a defense physiological response to osmotic stress. In Chapter III, the gas exchange response is shown in two genotypes of Stevia rebaudiana Bert. under five concentrations of salts. The most relevant results showed a differential behavior in the variables of gas exchange, DPV, internal leaf temperature and Ci / Ca, which could be explained by the effect of gene expression. While stomatal conductance and perspiration values did not report effects of NaCl doses and / or genotypes. The reduction in the rate of CO2 assimilation is associated with increased salinity but is not related to stomatal effects, suggesting an oxidative response of plants to saline stress conditions.