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Entre las diferentes acciones encaminadas a mejorar la tecnificación del cultivo de cacao (Theobroma cacao L.) se encuentra la optimización de sus condiciones de crecimiento. Identificar sus requerimientos nutricionales, es una de las estrategias que permite mejorar el material vegetal. Entre los nutrientes esenciales, se seleccionó el potasio como uno de los elementos fundamentales para la regulación de procesos hídricos, enzimáticos, iónicos y de osmorregulación. Así, se buscó profundizar en la optimización de los niveles de potasio para diferentes genotipos de cacao. En este estudio se evaluó el efecto de diferentes concentraciones y fuentes de K+ sobre características morfo-fisiológicas de cinco genotipos de T. cacao. Principalmente se encontraron diferencias en altura, longitud de raíz y biomasa, entre los clones CCN-51, FSA-13 y FEAR-5, siendo los dos primeros los que registraron valores superiores. Igualmente, se encontró una redistribución de la biomasa de la raíz y el vástago en las plantas crecidas con la menor concentración de potasio (0,16g/planta). Particularmente el índice raíz: vástago para el genotipo CCN-51 fue superior. Respecto a los parámetros fisiológicos se encontraron valores altos en conductancia estomática y fluorescencia de la clorofila para todos los genotipos independientemente de los tratamientos evaluados. Además, las variaciones genéticas entre los genotipos muestran respuestas diferenciales para las condiciones nutricionales evaluadas. Finalmente, los resultados sugieren que las plantas de cacao lograron un desarrollo adecuado al ser suplementadas con 0,16 g de K+ /planta en esta etapa de crecimiento, y ambas fuentes, KNO3 y KCl, son adecuadas para el suministro de este nutriente.

Cacao (Theobroma cacao L.) is an important commercial crop and agricultural commodity worldwide; for some Latin American countries, it is an essential part of export products. In Colombia, this crop has promising conditions to extend and strengthen this agriculture sector. However, their productivity is low under current agricultural practices, mainly due to insufficient modernization and inadequate or no management of their nutritional schemes. This publication reviewed the different findings currently in the scientific literature regarding the factors that determine the nutritional status of cacao plants, such as the function and distribution of minerals, nutritional efficiency, soil properties, establishment systems, organic and organic and inorganic sources examined. Additionally, it highlighted the importance of using and expanding diagnostic tools to determine nutritional needs and the design of effective programs according to the particular conditions of each region and the genotypes planted. This conceptual journey highlights the existing theoretical and experimental gap in the identification of the factors that determine the nutritional status of the plantations and their effect on the implementation of the fertilization programs used today. Information together provides elements to adequately address this agronomic practice and the economic impact on farmers and the cacao production chain.

Nutritional phosphate deficiency is a major limitation to plant growth. Here, we monitored fluxes in pathways supporting respiratory metabolism in potato (Solanum tuberosum) cell cultures growing in control or limiting phosphate conditions. Sugar uptake was quantified using [U-14C]sucrose as precursor. Carbohydrate degradation through glycolysis and respiratory pathways was estimated using the catabolism of [U-14C]sucrose to 14CO2. Anaplerotic carbon flux was assessed by labeling with NaH14CO3. The data showed that these metabolic fluxes displayed distinct patterns over culture time. However, phosphate depletion had relatively little impact on the various fluxes. Sucrose uptake was higher during the first six days of culture, followed by a decline, which was steeper in Pi-sufficient cells. Anaplerotic pathway flux was more important at day three and decreased thereafter. In contrast, the flux between sucrose and CO2 was at a maximum in the mid-log phase of the culture, with a peak at Day 6. Metabolization of [U-14C]sucrose into neutral, basic and acidic fractions was also unaffected by phosphate nutrition. Hence, the well-documented changes in central metabolism enzymes activities in response to Pi deficiency do not drastically modify metabolic fluxes, but rather result in the maintenance of the carbon fluxes that support respiration.