Efecto de campos electromagnéticos inducidos a baja intensidad sobre procesos morfo-fisiológicos y de productividad de Zea mays L. var Porva, como alternativa tecnológica sostenible para la producción agrícola

Tesis (Doctorado en Ciencias Naturales para el Desarrollo con énfasis en Sistemas de Producción Agrícola) Instituto Tecnológico de Costa Rica. Universidad Nacional de Costa Rica. Universidad Estatal a Distancia de Costa Rica, Doctorado en Ciencias Naturales para el Desarrollo, 2023.Al analizar la problemática del sector primario agrícola, se puede observar que la calidad de las semillas botánicas como material de propagación se convierte en una limitante productiva. Uno de los principales problemas que se registra en la literatura especializada en materia de propagación por semilla botánica es la dormancia seminal, lo que impacta al agricultor en el momento de siembra, puesto que tendrá que utilizar más semillas para la misma superficie o tendrá menor número de plantas por unidad de superficie. En el anterior contexto, este proyecto buscó evaluar el efecto que generan los campos electromagnéticos inducidos sobre las variables de crecimiento, desarrollo y productividad de plantas de Zea mays L. var Porva como alternativa tecnológica sostenible para la producción agrícola de este cultivo. Para ello, las semillas se sometieron, previo a la siembra, a tres intensidades de campo electromagnético (23, 70 y 118 µT) con cuatro tiempos de exposición (1, 3 y 5 horas diarias por 15 días y exposición permanente durante los 15 días), dejando un grupo control sin exposición a campos electromagnéticos. Se analizaron variables relacionadas con el proceso de germinación, entre ellas el porcentaje de germinación, la germinación diaria y acumulada, altura (cm), longitud de la raíz (cm), masa fresca aérea y de la raíz (g), así como masa seca aérea y de las raíces (g). Las variables anteriormente mencionadas se determinaron en dos momentos, exceptúan las relacionadas a la germinación, para determinar indicadores fisiológicos que describen el desarrollo del cultivo (Tasa de Crecimiento Relativo – TCR, Tasa de Asimilación Neta – TAN, Índice de Área Foliar – IAF, Tasa de Crecimiento de Cultivo – TCC, Tasa Absoluta de Crecimiento – TAC, Duración de Área Foliar – DAF y Área Foliar Especifica - AFE). Por otra parte, con la finalidad de caracterizar la producción, se evaluaron las características morfológicas de la mazorca y frutos (peso de la mazorca con amero, peso de tusa, peso de frutos y número de hileras), así mismo se extrajo el almidón del maíz para su caracterización por Microscopia Electrónica de Barrido, análisis cristalográfico por difracción de Rayos X, espectroscopia infrarroja por transformada de Fourier (FTIR) y Viscosidad Aparente. Se realizó la prueba de normalidad de Shapiro-Wilk y de Levene, esta última para establecer la homogeneidad de la varianza y así proceder al ANOVA. Finalmente se realizaron pruebas de rangos múltiples para establecer el comportamiento de las variables en comparación con el control. En todos los casos se empleó el software SPSS. En el anterior contexto experimental se evidencia que el proceso de germinación se vio estimulado por la aplicación de los campos electromagnéticos a intensidad media (70 µT), pero a sus más altos tiempos de exposición (300ˈ y Permanente durante 15 días), presentándose una conducta similar para germinación diaria, dinámica de germinación, longitud de la raíz y altura de la planta, similar a lo ocurrido la síntesis de pigmentos, biomasa fresca y seca, con exposición a 70 µT por 180ˈ, con su consiguiente reflejo en los indicadores fisiológicos evaluados, difiriendo siempre del control. Por otra parte, en materia de rendimiento del cultivo, los análisis estadísticos reflejan un mejor comportamiento de todas las variables analizadas para la exposición a 118 µT por 300ˈ y Permanente durante 15 días, difiriendo significativamente en la mayoría de las variables que componen este. Así mismo, en materia de variables de calidad del almidón extraído del maíz, es de resaltar que esta no se vio afectada al ser comparada con el control para ninguno de las pruebas efectuadas.When analyzing the problems of the primary agricultural sector, it can be observed that the quality of botanical seeds as propagation material becomes a productive constraint. One of the main problems reported in the specialized literature on botanical seed propagation is seed dormancy, which impacts the farmer at the time of planting, since he will have to use more seeds for the same area or will have fewer plants per unit area. In this context, this project sought to evaluate the effect of induced electromagnetic fields on the growth, development, and productivity variables of Zea mays L. var Porva plants as a sustainable technological alternative for the agricultural production of this crop. For this purpose, seeds were subjected, prior to sowing, to three electromagnetic field intensities (23, 70 and 118 µT) with four exposure times (1, 3 and 5 hours daily for 15 days and permanent exposure during the 15 days), leaving a control group without exposure to electromagnetic fields. Variables related to the germination process were analyzed, including germination percentage, daily and cumulative germination, height (cm), root length (cm), aerial and root fresh mass (g), as well as aerial and root dry mass (g). The variables were determined at two moments, except those related to germination, to determine physiological indicators that describe the development of the crop (Relative Growth Rate - RGR, Net Assimilation Rate - NAR, Leaf Area Index - LAI, Crop Growth Rate - CGR, Absolute Growth Rate - AGR, Leaf Area Duration - LAD and Specific Leaf Area - SFA). On the other hand, in order to characterize the production, the morphological characteristics of the ear and fruits were evaluated (weight of the ear with amero, weight of the cassava, weight of fruits and number of rows), likewise the starch of the corn was extracted for its characterization by Scanning Electron Microscopy, crystallographic analysis by X-Ray diffraction, Fourier Transform Infrared Spectroscopy (FTIR) and Apparent Viscosity. The Shapiro-Wilk and Levene normality tests were performed, the latter to establish homogeneity of variance and thus proceed to ANOVA. Finally, multiple range tests were performed to establish the behavior of the variables in comparison with the control. SPSS software was used in all cases. In the above experimental context, it is evident that the germination process was stimulated by the application of electromagnetic fields at medium intensity (70 µT), but at their highest exposure times (300ˈ and Permanent for 15 days), presenting a similar behavior for daily germination, germination dynamics, root length and plant height, similar to what occurred for pigment synthesis, fresh and dry biomass, with exposure to 70 µT for 180ˈ, with its consequent reflection in the physiological indicators evaluated, always differing from the control. On the other hand, in terms of crop yield, the statistical analyses reflect a better performance of all the variables analyzed for exposure to 118 µT by 300ˈ and Permanent for 15 days, differing significantly in most of the variables that compose it. Likewise, in terms of the quality variables of the starch extracted from corn, it should be noted that it was not affected when compared with the control for any of the tests performed

Nuevos registros de Harpacticoideos (Crustacea, Copepoda) en un sistema costero del norte de Colombia

Three species of harpacticoids are herein recorded from the zooplankton of Rodadero beach, Santa Marta, Magdalena, Colombia. Samples were collected from the littoral zone, mainly at inshore areas covered by mangrove vegetation and in an adjacent oyster bank. One of them, Laophonte cornuta Philippi, 1840 is new to the Colombian harpacticoid fauna, the other two species: Distioculus minor (Scott T., 1894) and Microsetella norvegica (Boeck, 1865) are new reports to the Magdalena department. This is the first illustrated record confirming their presence in Colombia and Magdalena, northern Colombia. Comparative morphological comments and illustrations of these species are also provided to document this report.Se registran tres especies de harpacticoides en el zooplancton de playa Rodadero, Santa Marta, Magdalena, norte de Colombia. Se recolectaron muestras en la zona litoral, principalmente en áreas costeras de manglar y en un banco de ostras. Una de ellas, Laophonte cornuta Philippi, 1840 es nueva para la fauna de harpacticoides de Colombia; las otras dos especies: Distioculus minor (Scott T., 1894) y Microsetella norvegica (Boeck 1865) son nuevos reportes para el departamento del Magdalena. Este es el primer registro ilustrado que confirma su presencia en Colombia y Magdalena. Se proporcionan comentarios morfológicos comparativos e ilustraciones de estas especies

Obtaining Composite Materials as an Alternative Use of Pineapple Residual Biomass for the Generation of Polymers Reinforced with Natural Fibers

One of the biggest problems in agricultural crops in general and, given its agronomic characteristics, in the pineapple crop, is the disposal of harvest residues. Currently, residues are removed and deposited in areas adjacent to the crop, becoming a focus of insect pests and diseases. Given the above context, the use of the afore mentioned foliar residues was evaluated as an alternative for obtaining composite materials from the plant's leaf fiber, thus generating added value to this residue. Initially, the leaves were subjected to three treatments to verify the effect on the tensile characteristics of the fibers. The treatments consisted of subjecting the leaves to fermentation at two temperatures (ambient and 30 °C) and in the presence of a NaOH solution [5%]. Subsequently, composite briquettes were made from pineapple fibers in proportions of 20 % and 30 % mixed with glycerol, guar gum, magnesium stearate and starch, evaluating the effect of the concentration of these fibers on the physico-mechanical properties of tension and elongation. Likewise, the effect of the use of a nanoclay in concentrations of 2.5 % and 5 % as reinforcement of the composite materials in a mixture with a fiber percentage of 20 % and 30 % was evaluated. In fermentation, significant differences (P>0.5) were found between the treatments, verifying that the best pretreatment was presented by the fermentation at room temperature with stress values of 373.33 ± 10.67 MPa, followed by the treatment at a temperature of 30 °C with 261.33 ± 23.09 MPa. On the other hand, when evaluating the tension and elongation, significant differences (P>0.5) were found between treatments, reporting values of 0.51 ± 0.03 MPa and 0.18 ± 0.0028 MPa for fiber concentrations of 20 % and 30 %, respectively. The effect of the use of nanoclay evidenced a higher strain in the treatment with 30 % fiber and 5 % nanoreinforcement with a value of 0.15 ± 0.0172 MPa

Use of Electromagnetic Fields as a Technological Alternative for the Production of Biomasa in Zea Mays L. Var Porva and Reduction of the Carbon Footprint of the Crop

In recent years, the use of electromagnetic fields as an enhancer of biological processes in agriculture has emerged as an emerging technology. This is closely related to the carbon footprint, since plants in general and higher plants in particular, through the photosynthesis process, reduce the atmospheric carbon load, converting it into structural carbon of the plant itself. Thus, this research sought to evaluate the effect generated by induced electromagnetic fields (EMF) as a technology for biomass production, with the consequent reduction of the carbon footprint of the crop. Variables related to the germination process were analyzed, including germination percentage, aerial and root fresh mass (g), as well as aerial and root dry mass (g), and photosynthetic pigment contents (Chlorophylls A, B and Total). The aforementioned variables were determined at two points in time, except those related to germination. The above variables, evaluated at two points in time, allowed the calculation of physiological indicators related to CO2 use in the plant (Relative Growth Rate - RGR, Net Assimilation Rate - NAR, Leaf Area Index - FAI, Crop Growth Rate - CGR, Absolute Growth Rate - AGR, Leaf Area Duration - LAD and Specific Leaf Area - SFA). On the other hand, in order to characterize the production, the morphological characteristics of the ear and fruit (weight of the ear with amero, weight of the cassava, weight of the fruit and number of rows) were evaluated. Multiple range tests were carried out to establish the behavior of the variables in comparison with the control, for which SPSS software was used. In the previous experimental context, it was evidenced that the germination process was stimulated by the application of EMF at 70 µT, but at its highest exposure times (300' and Permanent for 15 days. Similar to the above, was presented in pigment synthesis, fresh and dry biomass, with exposure at 70 µT for 180', with its consequent reflection in the physiological indicators evaluated, differing in all cases from the control. On the other hand, in terms of cob composition, the statistical analyses reflect a better performance of all the variables analyzed for exposure to 118 µT by 300' and Permanent for 15 days, differing significantly in most of the variables evaluated

Efecto de campos electromagnéticos inducidos a baja intensidad sobre procesos morfo-fisiológicos y de productividad de Zea mays L. var Porva, como alternativa tecnológica sostenible para la producción agrícola

Suárez Rivero, D. (2023). Efecto de campos electromagnéticos inducidos a baja intensidad sobre procesos morfo-fisiológicos y de productividad de Zea mays L. var Porva, como alternativa tecnológica sostenible para la producción agrícola. [Tesis de Licenciatura]. Tecnológico de Costa Rica, Cartago.Al analizar la problemática del sector primario agrícola, se puede observar que la calidad de las semillas botánicas como material de propagación se convierte en una limitante productiva. Uno de los principales problemas que se registra en la literatura especializada en materia de propagación por semilla botánica es la dormancia seminal, lo que impacta al agricultor en el momento de siembra, puesto que tendrá que utilizar más semillas para la misma superficie o tendrá menor número de plantas por unidad de superficie. En el anterior contexto, este proyecto buscó evaluar el efecto que generan los campos electromagnéticos inducidos sobre las variables de crecimiento, desarrollo y productividad de plantas de Zea mays L. var Porva como alternativa tecnológica sostenible para la producción agrícola de este cultivo. Para ello, las semillas se sometieron, previo a la siembra, a tres intensidades de campo electromagnético (23, 70 y 118 µT) con cuatro tiempos de exposición (1, 3 y 5 horas diarias por 15 días y exposición permanente durante los 15 días), dejando un grupo control sin exposición a campos electromagnéticos. Se analizaron variables relacionadas con el proceso de germinación, entre ellas el porcentaje de germinación, la germinación diaria y acumulada, altura (cm), longitud de la raíz (cm), masa fresca aérea y de la raíz (g), así como masa seca aérea y de las raíces (g). Las variables anteriormente mencionadas se determinaron en dos momentos, exceptúan las relacionadas a la germinación, para determinar indicadores fisiológicos que describen el desarrollo del cultivo (Tasa de Crecimiento Relativo – TCR, Tasa de Asimilación Neta – TAN, Índice de Área Foliar – IAF, Tasa de Crecimiento de Cultivo – TCC, Tasa Absoluta de Crecimiento – TAC, Duración de Área Foliar – DAF y Área Foliar Especifica - AFE). Por otra parte, con la finalidad de caracterizar la producción, se evaluaron las características morfológicas de la mazorca y frutos (peso de la mazorca con amero, peso de tusa, peso de frutos y número de hileras), así mismo se extrajo el almidón del maíz para su caracterización por Microscopia Electrónica de Barrido, análisis cristalográfico por difracción de Rayos X, espectroscopia infrarroja por transformada de Fourier (FTIR) y Viscosidad Aparente. Se realizó la prueba de normalidad de Shapiro-Wilk y de Levene, esta última para establecer la homogeneidad de la varianza y así proceder al ANOVA. Finalmente se realizaron pruebas de rangos múltiples para establecer el comportamiento de las variables en comparación con el control. En todos los casos se empleó el software SPSS. En el anterior contexto experimental se evidencia que el proceso de germinación se vio estimulado por la aplicación de los campos electromagnéticos a intensidad media (70 µT), pero a sus más altos tiempos de exposición (300ˈ y Permanente durante 15 días), presentándose una conducta similar para germinación diaria, dinámica de germinación, longitud de la raíz y altura de la planta, similar a lo ocurrido la síntesis de pigmentos, biomasa fresca y seca, con exposición a 70 µT por 180ˈ, con su consiguiente reflejo en los indicadores fisiológicos evaluados, difiriendo siempre del control. Por otra parte, en materia de rendimiento del cultivo, los análisis estadísticos reflejan un mejor comportamiento de todas las variables analizadas para la exposición a 118 µT por 300ˈ y Permanente durante 15 días, difiriendo significativamente en la mayoría de las variables que componen este. Así mismo, en materia de variables de calidad del almidón extraído del maíz, es de resaltar que esta no se vio afectada al ser comparada con el control para ninguno de las pruebas efectuadas.When analyzing the problems of the primary agricultural sector, it can be observed that the quality of botanical seeds as propagation material becomes a productive constraint. One of the main problems reported in the specialized literature on botanical seed propagation is seed dormancy, which impacts the farmer at the time of planting, since he will have to use more seeds for the same area or will have fewer plants per unit area. In this context, this project sought to evaluate the effect of induced electromagnetic fields on the growth, development, and productivity variables of Zea mays L. var Porva plants as a sustainable technological alternative for the agricultural production of this crop. For this purpose, seeds were subjected, prior to sowing, to three electromagnetic field intensities (23, 70 and 118 µT) with four exposure times (1, 3 and 5 hours daily for 15 days and permanent exposure during the 15 days), leaving a control group without exposure to electromagnetic fields. Variables related to the germination process were analyzed, including germination percentage, daily and cumulative germination, height (cm), root length (cm), aerial and root fresh mass (g), as well as aerial and root dry mass (g). The variables were determined at two moments, except those related to germination, to determine physiological indicators that describe the development of the crop (Relative Growth Rate - RGR, Net Assimilation Rate - NAR, Leaf Area Index - LAI, Crop Growth Rate - CGR, Absolute Growth Rate - AGR, Leaf Area Duration - LAD and Specific Leaf Area - SFA). On the other hand, in order to characterize the production, the morphological characteristics of the ear and fruits were evaluated (weight of the ear with amero, weight of the cassava, weight of fruits and number of rows), likewise the starch of the corn was extracted for its characterization by Scanning Electron Microscopy, crystallographic analysis by X-Ray diffraction, Fourier Transform Infrared Spectroscopy (FTIR) and Apparent Viscosity. The Shapiro-Wilk and Levene normality tests were performed, the latter to establish homogeneity of variance and thus proceed to ANOVA. Finally, multiple range tests were performed to establish the behavior of the variables in comparison with the control. SPSS software was used in all cases. In the above experimental context, it is evident that the germination process was stimulated by the application of electromagnetic fields at medium intensity (70 µT), but at their highest exposure times (300ˈ and Permanent for 15 days), presenting a similar behavior for daily germination, germination dynamics, root length and plant height, similar to what occurred for pigment synthesis, fresh and dry biomass, with exposure to 70 µT for 180ˈ, with its consequent reflection in the physiological indicators evaluated, always differing from the control. On the other hand, in terms of crop yield, the statistical analyses reflect a better performance of all the variables analyzed for exposure to 118 µT by 300ˈ and Permanent for 15 days, differing significantly in most of the variables that compose it. Likewise, in terms of the quality variables of the starch extracted from corn, it should be noted that it was not affected when compared with the control for any of the tests performed.Tecnológico de Costa RicaUniversidad Nacional, Costa RicaUniversidad Estatal a Distancia, Costa RicaDepartamento de FísicaDOCINAD

Evaluation of the effect of two types of fertilizer on the growth, development and productivity of hydroponic green forage Oat (Avena sativa L.) and Ryegrass (Lolium multiflorum Lam.) as a biomass source

Hydroponic Green Forage (HGF) is increasingly being internationally recognized as an alternative to ensure sustainable biomass production per unit area in the shortest possible time and at the highest possible quality. This research thus evaluates the effect of two nutrient solutions (with two dilutions in each case) applied in the HGF production system for Oats and Ryegrass on the parameters of growth, development and productivity of both species. To this end, a handmade greenhouse was built in which two seed sowing trays were installed with a fertigation system for oats and ryegrass species. The experimental design consisted of the assembly of two modules of 24 seed trays in which HGF Oat and Ryegrass were grown using two nutrient solutions (which were applied according to the position of the seed trays inside the module at level 2 and level 4). The tests showed for the two species evaluated that the use of organic solutions significantly promote the conversion and yield variables of fresh mass per unit area - an increase in the relative growth rate, the net assimilation rate, the crop growth rate and the absolute growth rate; all of these as a measure of crop development. Likewise, when the analysis was conducted, it was observed that the most economic assemblies turned out to be those which used the liquid humus as nutrient solution to 1/20 v.v. and 1/40 v.v. This supports the conclusion that the use of organic nutrient solution can yield high quality HGF exceeding the development parameters of those produced using conventional (synthetic) nutrient [email protected]

Potencial antioxidante de los extractos obtenidos del pericarpio y la semilla del fruto de garcinia mangostana l. según el método de extracción

Estudios científicos han demostrado que los métodos de extracción de soluciones de materias primas vegetales, pueden afectar negativamente la capacidad antioxidante de las mismas. Por otra parte, el estudio del uso potencial de los residuos (exocarpio y semilla) garantiza la generación de valor agregado a las cadenas productivas, y con ello una significativa disminución de emisión de estos a vertederos. Esta investigación evaluó el potencial antioxidante del epicarpio y semillas de frutos de Garcinia mangostana L. con el empleo de tres métodos de extracción (Soxhlet, hidrodestilación y arrastre por vapor) usando etanol absoluto como solvente y agua. Se empleó como matriz grasa una muestra de aceite comercial de soya y otra de Butilhidroxitolueno (BHT) que se corresponde a un antioxidante de origen sintético. En el pericarpio de G. mangostana L., los métodos de extracción Soxhlet y arrastre de vapor mostraron valores relevantes, denotando un efecto antioxidante sobre el aceite de soya por reducción del índice de peróxidos. Para la semilla, el método arrastre de vapor muestra valores de manera creciente junto a la concentració[email protected]@[email protected]@[email protected]

The effect of magnetic and electromagnetic fields on the morpho-anatomical characteristics of corn (Zea mays l.) during biomass production

There are several sources of raw material that have been identified worldwide with some potential to be used for the production of biofuels; for this reason hard work has been put into increasing the yields per unit area and increasing the sugar content (as in the case of corn). There are only a small number of studies that have analyzed the morpho-anatomical behaviour of crops modified for biomass production. For this reason, this work studied the morpho-anatomical, developmental and physiochemical changes in Zea mays L. plants when exposed to magnetic and electromagnetic fields with a view to the large-scale production of biomass for the generation of biofuels. Seeds were exposed to different fields for 21 days, with a control group of seeds that were not exposed. Sowing was carried out in 100 cm3 trays using coconut fiber as a substrate. The substrate had been disinfected and moistened prior to use. The sowing trays were placed in a semi-controlled growth chamber at a light intensity of 3,000 lux, with light cycles of 12 hours and at a temperature of 23°C. The variables studied were the growth dynamics of coleoptiles and plants, the complete bromatological analysis and the anatomical structure. The bromatological analysis included the percentage variation of dry matter, crude protein, ether extract, ash content, organic matter, crude fibre, neutral detergent fibre (NDF), acid detergent fibre (ADF) and calcium, lignin and water activity. The anatomical structure was studied to identify relevant histological changes and mainly focused on the arrangement of parenchymatous tissue and the shape of the cells of which it is comprised. In addition, evaluations were conducted regarding the development of the crop based on the following indicators: relative growth rate, net assimilation rate, leaf area index, crop growth rate, absolute growth rate, leaf area duration and specific leaf area. The best results were obtained on plants whose seeds were treated with electromagnetic fields. A significant increase was seen in the majority of the indicators studied. This was most evident in the development of the parenchymal tissue and thus the chlorophyll content, as was clearly seen in the histological sections. It is important to emphasize that the histological technique allowed us to identify areas of the greatest concentrations of chlorophyll (shown by differing shades of green) in plants whose seeds had been subjected to electromagnetic fields. An increase in the chlorophyll level gives us an indirect measure of the high potential these plants offer for producing [email protected]@ucc.edu.c