Efecto de aplicaciones de calcio, magnesio y ácido giberélico sobre la firmeza de baya de uva de mesa en etapas de desarrollo, postcosecha y ensayo in-vitro
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Fecha
2017
Profesor/a Guía
Facultad/escuela
Idioma
es
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Universidad Andrés Bello
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Licencia CC
Licencia CC
Resumen
La exportación de fruta fresca es una de las principales fuentes de ingresos económicas de Chile, donde la uva de mesa es la especie más importante. Una vez cosechados, los racimos de uva deben llegar a sus mercados de destino, implicando un largo tiempo de almacenamiento. Por lo tanto, los parámetros de calidad de los frutos disminuyen, y la firmeza de la baya es uno de los caracteres más afectados, resultando en una reducción de las ganancias para los productores. La firmeza es un parámetro que varía a lo largo del desarrollo de la baya de uva, mostrando una menor firmeza en la cosecha que en las etapas inmaduras. Aplicaciones exógenas de iones minerales y hormonas vegetales son utilizadas para mejorar la firmeza en la cosecha. En el presente trabajo, se propuso comprender los mecanismos fisiológicos y bioquímicos asociados con la firmeza durante el desarrollo de la uva de mesa cv. Thompson Seedless cultivadas in-vitro. El sistema de cultivo in-vitro simula la vía endógena de absorción de nutrientes para estudiar los efectos de los iones calcio (Ca+2) y magnesio (Mg+2) junto con el ácido giberélico (GA3) y su posible relación con la firmeza de las bayas. Además, se realizaron evaluaciones en bayas de uva en el campo durante las etapas de desarrollo y postcosecha utilizando los mismos tratamientos. Los resultados de los ensayos in-vitro indicaron un aumento en la firmeza de las bayas tratadas con calcio. Sin embargo, las bayas bajo tratamientos con magnesio mostraron un aumento en el contenido de ácidos urónicos y en la cantidad de azúcares neutros de la pared celular. Además, se observó un aumento en la actividad poligalacturonasa (PG) y β-galactosidasa (β-gal). Adicionalmente, bayas de campo bajo tratamientos con magnesio y ácido giberélico mostraron un aumento en peso, diámetro y firmeza. Además, estas bayas mostraron una disminución en la actividad de las enzimas PG y β-gal. Estos resultados sugieren que el calcio y el magnesio interactúan con la pared celular y podrían estar involucrados en la dinámica del remodelamiento de ésta.
Fresh fruit export is one of the main sources of economic income in Chile, where table grape is the most important species. Once harvested, grape clusters must reach their target markets, resulting in long storage times. Therefore, the quality parameters of the fruits decrease, and the firmness of the berry is one of the most affected traits, resulting in a reduction of the profits for the producers. Firmness is a parameter that oscillates throughout the development of the grape berry, showing a lower firmness at the harvest than at the immature stages. Exogenous applications of mineral ions and plant hormones are used to improve firmness at the harvest. In the present work, it was proposed to understand the physiological and biochemical mechanisms associated with firmness during the development of table grape cv. Thompson Seedless cultured in-vitro. The in-vitro culture system simulates the endogenous nutrient uptake pathway to study the effects of calcium (Ca+2) and magnesium (Mg+2) ions along with gibberellic acid (GA3) and its possible relationship with the firmness of the berry. In addition, evaluations were made in grape berries in the field during the developmental and post-harvest stages using the same treatments. The results of the in-vitro assays indicated an increase in the firmness of the calcium treated berries. However, berries under treatments using magnesium showed an increase in the content of uronic acids and the amount of neutral sugars of the cell wall. Furthermore, an increase in the activity of polygalacturonase (PG) and β-galactosidase (β-gal) was observed. Additionally, field berries under treatments using magnesium and gibberellic acid showed an increase in weight, diameter and firmness. Also, these berries showed a decrease in the activity of the enzymes PG and β-gal. These results suggest that calcium and magnesium interact with the cell wall and may be involved in the dynamics of cell wall remodeling.
Fresh fruit export is one of the main sources of economic income in Chile, where table grape is the most important species. Once harvested, grape clusters must reach their target markets, resulting in long storage times. Therefore, the quality parameters of the fruits decrease, and the firmness of the berry is one of the most affected traits, resulting in a reduction of the profits for the producers. Firmness is a parameter that oscillates throughout the development of the grape berry, showing a lower firmness at the harvest than at the immature stages. Exogenous applications of mineral ions and plant hormones are used to improve firmness at the harvest. In the present work, it was proposed to understand the physiological and biochemical mechanisms associated with firmness during the development of table grape cv. Thompson Seedless cultured in-vitro. The in-vitro culture system simulates the endogenous nutrient uptake pathway to study the effects of calcium (Ca+2) and magnesium (Mg+2) ions along with gibberellic acid (GA3) and its possible relationship with the firmness of the berry. In addition, evaluations were made in grape berries in the field during the developmental and post-harvest stages using the same treatments. The results of the in-vitro assays indicated an increase in the firmness of the calcium treated berries. However, berries under treatments using magnesium showed an increase in the content of uronic acids and the amount of neutral sugars of the cell wall. Furthermore, an increase in the activity of polygalacturonase (PG) and β-galactosidase (β-gal) was observed. Additionally, field berries under treatments using magnesium and gibberellic acid showed an increase in weight, diameter and firmness. Also, these berries showed a decrease in the activity of the enzymes PG and β-gal. These results suggest that calcium and magnesium interact with the cell wall and may be involved in the dynamics of cell wall remodeling.
Notas
Tesis (Magíster en Biotecnología)
Palabras clave
Uva de Mesa, Calidad, Mejoramiento