Pigmentos fotosintéticos de Stevia rebaudiana Bert en condiciones diferenciales de luz solar y fertilización nitrogenada en invernadero

Contextualization: The areas planted with stevia have been growing significantly in response to the new trends in consumption of low-calorie and natural foods. The effects of high radiation levels, due to global climate change, have evidenced the need to development new studies about the physiological behavior of the photosynthetic pigments of agricultural species. Knowledge gap: The lack of knowledge of the behavior of stevia crops in the context of current and future environmental changes (mainly, the increases in solar radiation levels) means that farmers and producers do not obtain the expected yields. Purpose: The objective of this study was analyze the effect of different levels of solar radiation and nitrogen fertilization, under greenhouse conditions, on the production of photosynthetic pigment in Stevia rebaudiana Bert. Methodology: The trial was done using as completely randomized design (CRD), employing a 2 x 6 factorial arrangement and 16 replicates per treatment; factor A corresponded to two levels of incident solar radiation (300 and 1500 μmol photons. m-2 s-1 corresponding to 20 % and 100 % radiation respectively) and factor B corresponded to six doses of nitrogen (0, 60, 120, 180, 240 and 300 kg ha-1). Chlorophyll a, b, and total chlorophyll content was evaluated in young and healthy leaves eight months after transplanting. Results and conclusions: The results showed that the contents of chlorophyll a, b and total were significantly affected by solar radiation, but not by the nitrogen supplied. In both radiation environments, the contents of chlorophyll a were higher than the contents of chlorophyll b in all plants evaluated. In the environment of lower solar radiation (300 µmol of photons m-2 s-1), the maximum levels of the photosynthetic pigments were presented. In the environment of 1500 µmol of photons. m-2 s-1, the contents of chlorophyll a, b and total were lower in control plants (0 kg ha-¹). Contextualización: El área de siembra del cultivo de estevia ha venido creciendo de manera significativa, debido a las nuevas tendencias de consumo de alimentos naturales, bajos en calorías. Los efectos de las altas radiaciones, debidas al cambio climático global, han evidenciado la necesidad de desarrollar nuevos estudios sobre el comportamiento fisiológico de los pigmentos fotosintéticos de las especies agrícolas. Vacío de conocimiento: El desconocimiento del comportamiento de los cultivos de estevia frente a los cambios act