Browsing by Author "Albornoz G., Francisco"

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    Evaluación de las propiedades ópticas en hojas de plantas de lechuga (Lactuca sativa L.) para el diagnóstico temprano de déficit de nutrientes
    (2022) Salazar Ruiz, Natalia; Albornoz G., Francisco; Pontificia Universidad Católica de Chile. Facultad de Agronomía e Ingeniería Forestal
    Las propiedades ópticas de las hojas pueden ser utilizadas para el diagnóstico de deficiencias nutricionales, en menos tiempo y a menor costo que las técnicas tradicionales. Los objetivos de esta investigación fueron determinar el efecto de las deficiencias nutricionales en las propiedades ópticas de las hojas en plantas de lechuga (Lactuca sativa L.), comparar la evaluación de propiedades ópticas con la medición de contenido de clorofila para el diagnóstico de deficiencias nutricionales y seleccionar índices de vegetación que permitieran determinar déficits nutricionales de forma temprana. La metodología utilizada se basó en la medición de la reflectancia, transmitancia y absorbancia de las hojas por medio de un espectrofotoradiómetro y el contenido de clorofila con un medidor portátil. Los resultados obtenidos indican que las propiedades ópticas y los índices de vegetación pueden ser utilizados para el diagnóstico temprano de deficiencias nutricionales, sin embargo, se debe considerar su sensibilidad a las condiciones ambientales y la especie y variedad evaluada, por lo que los déficits nutricionales específicos, requieren un mayor refinamiento y análisis de los datos y su interacción con otras variables, es necesario realizar futuras evaluaciones para analizar la interacción entre estas. Palabras clave: Deficiencias nutricionales, propiedades ópticas, clorofila, índices de vegetación.
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    Fog water collection for local greenhouse vegetable production in the Atacama Desert
    (2023) Albornoz G., Francisco; Río López, Camilo del; Carter Gamberini, María Virginia; Escobar Moragas, Rodrigo; Vásquez Gimeno, Lucas Simón
    Agricultural production in the Atacama Desert is restricted by extreme aridity and poor soil quality. Between 18° S and 30° S, low stratocumulus clouds regularly cover the southeastern Pacific Ocean reaching the Coastal Cordillera. Thus, marine fog is constantly present in the coastal areas of the desert. Fog can be harvested using fog collectors. However, limited information is available with regards to the variability of fog presence throughout the year and along the coast of the desert. Combining fog water harvest with hydroponic production under greenhouse facilities presents an alternative for sustainable and local fresh food production. In this article, we analyze the potential of fog water collection in two sites (Alto Patache and Falda Verde) distant by about 1000 km within the Atacama Desert. Additionally, in both locations, the environmental conditions within greenhouse structures, the potential energy requirement for environmental conditioning (including the energy production from photovoltaic panels) and the water requirements of vegetable crops under greenhouse conditions were modeled. The annual average of fog water collection registered was 2.9 and 3.3 L per day per m2 in Alto Patache and Falda Verde, respectively. During the most demanding season for crop evapotranspiration, 2.13 m2 of fog collectors can supply the water required for 1 m2 of greenhouse crops. The energy required for water and air pumps in the hydroponic systems can be supplied with photovoltaic systems including eight PV modules and a battery storage capacity of 9.4 kWh. In conclusion, the present study sheds light on the possibilities of massive water collection from fog to be used in local and sustainable food production in the Atacama Desert.
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    Screening for indole-3-acetic acid synthesis and 1-aminocyclopropane-carboxylate deaminase activity in soil yeasts from Chile uncovers Solicoccozyma aeria as an effective plant growth promoter
    (2023) Carvajal Contardo, Mariajosé; Godoy, Liliana; Gebauer H., Marlene; Catrileo Aros, Daniela; Albornoz G., Francisco
    Background and aims: Plant growth-promoting microorganisms (PGPMs) stimulate plant growth by a series of mechanisms, including atmospheric nitrogen fixation, phosphorus solubilization and the synthesis of plant hormones. Within the group of PGPMs, several species of bacteria and fungi have been extensively studied. However, little information is available with regard to soil yeasts. The present study was conducted to identify yeast strains isolated from different soils in Chile that present plant growth promotion activity. Methods: Twenty-three strains were evaluated either for their capacity to synthesize indole-3-acetic acid or show aminocyclopropane-1-carboxylate deaminase activity. The effect on tomato seedling growth was evaluated in vitro, and two strains were selected for in vivo evaluation of plant growth and root ethylene synthesis. Results: All the strains analyzed presented IAA synthesis within the range between 0.8 and 3.3 ?g IAA mL?1. Solicoccozyma aeria (YCPUC75 and YCPUC79 strains) was the only yeast with ACC deaminase activity. In vitro inoculation of tomato seeds with eight of the evaluated strains resulted in an increase in the root volume and the number of lateral roots. In the second experiment, a 40% reduction in root ethylene synthesis was achieved by adding S. aeria (YCPUC79) to the root zone, which resulted in a 26% increase in plant growth. Conclusions: Solicoccozyma aeria YCPUC79 is an effective plant growth promoter stimulating root growth and reducing root ethylene synthesis.