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Efectos de la aplicación de CSL en plantas hortícolas para mejorar su crecimiento en diferentes condiciones medioambientales


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Título :
Efectos de la aplicación de CSL en plantas hortícolas para mejorar su crecimiento en diferentes condiciones medioambientales
Autor :
Navarro Morillo, Iván  
Tutor:
Garcia-Sanchez, Francisco  
Cámara-Zapata, José-María  
Editor :
Universidad Miguel Hernández
Fecha de publicación:
2024-04-16
URI :
https://hdl.handle.net/11000/34065
Resumen :
La exposición de las plantas a condiciones ambientales adversas ha cobrado una importancia creciente en la agricultura moderna, especialmente en situación de cambio climático. Entre dichas condiciones ambientales estresantes para los cultivos podemos encontrar la radiación ultravioleta (UV) que pue...  Ver más
The exposure of plants to adverse environmental conditions has gained increasing importance in modern agriculture, particularly in this situation of climate change. Among these stressful environmental conditions for crops, we can find ultraviolet (UV) radiation, which can cause sunburn and molecular damage in plants, negatively affecting their photosynthesis and metabolism. Also, soil salinity can interfere with the absorption of water and nutrients, causing osmotic imbalances and ionic toxicity in plants. On the other hand, with the sustained increase in the world population, excessive nitrogen fertilization has been carried out to increase crop productivity without increasing the cultivated space, causing environmental problems. These factors can negatively impact crop development and human health. In this context, research on methods to improve plant resistance and nutrient use efficiency is crucial. Among these methods, the use of plant-derived biostimulants has been studied. One of these biostimulants is corn steep liquor (CSL), a by-product derived from the corn processing industry, which contains many molecules that can act as biostimulants, but its specific effects, as well as the mode and timing of application, have not been thoroughly investigated. In this context, this thesis focuses on evaluating different forms of CSL as a biostimulant, its mode of action, and its impact, both on plants subjected to environmental stress conditions (UV radiation and high salinity), and on the efficiency of nitrogen fertilization. Four experiments were carried out to determine the biostimulant effect and which forms of application are most effective in increasing resilience in crops. The crops selected for the experiments were cucumber and pepper, due to their relevance in agriculture and their known sensitivity to these types of environmental stress. Cucumber, for example, is particularly susceptible to damage caused by UV radiation, while pepper shows notable sensitivity to soil salinity. In the first experiment, it was evaluated whether CSL improved the growth and development of pepper plants under controlled conditions. For this reason, four treatments were carried out with two types of CSL (CSL-H and CSL-B), differentiated by their stabilization method, and applied both foliarly and radicularly. The objective was to determine which method of application and type of CSL was most effective in terms of promoting vegetative growth and development in pepper plants. In the second experiment, it was analyzed whether the application of CSL mitigated the absorption and accumulation of toxic ions and their phytotoxicity in pepper plants grown under saline stress conditions. For this, four treatments were carried out in a growth chamber: irrigation with nutrient solution; irrigation with 100 mM NaCl in the nutrient solution; irrigation with 100 mM NaCl in the nutrient solution and foliar application of CSL at 5 mL L−1 every 7 days; and irrigation with 100 mM NaCl in the nutrient solution and radicular application of CSL at 5 mL L−1 every 7 days. This approach allowed determining the most effective method of CSL application (foliar and/or radicular) to reduce the phytotoxic effects of saline stress in plants. In the third experiment, it was investigated whether the application of the protective producto Archer® Eclipse, whose composition includes CSL, mitigated sunburn damage and its associated effects on cucumber plants grown under conditions that induce sunburn. To this end, two treatments were established: untreated plants (control) and plants sprayed with Archer® Eclipse. The objective was to determine the efficacy of Archer® Eclipse in reducing the symptoms of sunburn and in improving parameters such as biomass, leaf temperature, photosynthesis, and oxidative stress in plants. Plants treated with Archer® Eclipse were compared with untreated ones to evaluate significant differences in resistance to conditions of intense solar radiation and high temperatures. In the fourth experiment, it was assessed whether the application of CSL mitigated the effects of nitrogen reduction in pepper plants grown at different concentrations of nitrogen fertilization. For this, four treatments were established that varied in the amount of nitrogen provided (100% N, 75% N, 50% N, and 25% N) and the type of CSL application (without CSL, foliar CSL, and radicular CSL) to determine the most effective form of CSL application in terms of reducing the negative effects of nitrogen limitation in plants. The treatments were designed to investigate how CSL application could improve nitrogen use efficiency (NUtE and NUE), increasing nitrogen assimilation (increase in enzymatic activities) and the concentration of amino acids and proteins under conditions of reduced nitrogen supply. From these experiments, the most relevant conclusions were as follows: I. First experiment: The results obtained showed that the application of CSL products (both CSL-B and CSL-H) in pepper plants resulted in a significant increase in vegetative growth compared to control plants. This increase in growth was due to: (i) the rich composition of CSL products, which includes free amino acids, humic and fulvic acids, and nutrients such as organic nitrogen, potassium, and phosphorus, and (ii) the stimulation of physiological and biochemical processes in plants, including carbon metabolism, water use efficiency, and hormonal synthesis. In addition, it was observed that the application of CSL through the roots was more effective than foliar application. CSL at low doses (5 mL L−1) not only increased plant biomass but also improved the absorption and concentration of essential nutrients in the leaves. II. Second experiment: The results obtained showed that CSL, especially radicular application, significantly improved the growth of pepper plants subjected to high salinity. It was observed that radicular application of CSL maintained photochemical activity and stimulated photosynthetic efficiency, which, along with a higher foliar concentration of K+ and a reduction of stomatal closure under saline stress, allowed a high rate of net photosynthesis and reduced ROS generation, thus counteracting the phytotoxic effect of Na+ ions. III. Third experiment: The results obtained showed that treatment with Archer® Eclipse in cucumber plants under high light and temperature stress conditions resulted in a significant increase in plant growth and biomass. In addition, it was observed that treatment with Archer® Eclipse did not negatively affect the mechanisms of gas exchange regulation in plants. On the other hand, untreated plants showed an increase in their antioxidant response, indicating more intense stress compared to treated plants. These findings suggest that Archer® Eclipse offers effective protection against conditions that induce sunburn in cucumber plants. IV. Fourth experiment: The results obtained showed that reductions up to 50% and 25% in nitrogen concentration (N-50% and N-25%) caused a notable decrease in biomass and leaf area of the plants. However, the application of CSL, especially radicular, showed a significant capacity to mitigate these negative effects. CSL improved nitrogen assimilation, increased its use efficiency, and increased the synthesis of amino acids and proteins. Unlike foliar application, which had a limited impact, radicular application of CSL proved to be an effective strategy for improving the growth and health of pepper plants under nitrogen deficiency conditions
Notas:
Programa de Doctorado en Recursos y Tecnologías Agrarias, Agroambientales y Alimentarias
Palabras clave/Materias:
Cultivos hortícolas
Bioestimulantes
Estrés en los cultivos
Licor de maceración de maíz (CSL)
Radiación UV
Salinidad
Tipo de documento :
info:eu-repo/semantics/doctoralThesis
Derechos de acceso:
info:eu-repo/semantics/openAccess
Attribution-NonCommercial-NoDerivatives 4.0 Internacional
Aparece en las colecciones:
Tesis doctorales - Ciencias e Ingenierías



Creative Commons La licencia se describe como: Atribución-NonComercial-NoDerivada 4.0 Internacional.