Propagación sexual y descripción morfoanatomica del proceso germinativo del ñirre (Nothofagus antarctica).
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Date
2024
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Universidad de Concepción
Abstract
Nothofagus antarctica, comúnmente conocido como ñirre, es la especie con mayor amplitud ecológica en Chile, abarcando una franja geográfica de aproximadamente 2.300 km. Esta especie, monoica y caducifolia se adapta a una amplia variedad de biotipos extremos, alcanzando alturas que van desde los 60 cm hasta los 25 m; además, es reservorio de productos forestales no madereros, con aplicaciones en usos ornamentales, comestibles y medicinales, además de ofrecer diversos servicios medioambientales. A pesar de su versatilidad, presenta una baja capacidad de dispersión, y su propagación es predominantemente asexual. El objetivo es evaluar el efecto de distintos tratamientos en la germinación de semillas de N. antarctica y describir los cambios morfoanatomicos durante el proceso germinativo. Para ello, se realizaron dos experimentos de germinación, en los cuales se evaluaron tanto el porcentaje de germinación como la velocidad de germinación. El primer experimento consistió en escarificación con ácido sulfúrico entre 0 y 20 minutos, junto con una estratificación fría entre 30 y 100 días. En el segundo experimento, se lavaron las semillas con agua a temperaturas de 25 °C y 50 °C, y se aplicó ácido giberélico (AG3) a distintas concentraciones. Los resultados mostraron que no hubo diferencias significativas en los porcentajes de germinación; sin embargo, se observó que un mayor tiempo de exposición al frío incrementó el índice de velocidad de germinación, mientras que el lavado de semillas con agua a 50 °C ralentizó la velocidad de germinación. Además, el crecimiento de las semillas fue asincrónico y mediante microscopia electrónica de barrido se identificaron diversas estructuras y características anatómicas relevantes para el proceso germinativo.
Nothofagus antarctica, commonly known as ñirre, is the species with the greatest ecological amplitude in Chile, covering a geographic range of approximately 2,300 km. This species, monoecious and deciduous, adapts to a wide variety of extreme biotypes, reaching heights ranging from 60 cm to 25 m; it is also a reservoir of non-timber forest products, with applications in ornamental, edible and medicinal uses, in addition to offering various environmental services. Despite its versatility, it has a low dispersal capacity, and its propagation is predominantly asexual. The objective of this research is to identify an effective method for the sexual propagation of N. antarctica seeds, as well as to describe the morphoanatomical changes that occur during the germination process. For this purpose, two germination experiments were carried out, in which both germination percentage and germination speed were evaluated. The first experiment consisted of scarification with sulfuric acid between 0 and 20 minutes, together with cold stratification between 30 and 100 days. In the second experiment, seeds were washed with water at temperatures of 25 °C and 50 °C, and gibberellic acid (AG3) was applied at different concentrations. The results showed that there were no significant differences in germination percentages; however, it was observed that longer exposure to cold increased the germination speed index, while washing seeds with water at 50 °C slowed the germination speed. In addition, seed growth was asynchronous, and scanning electron microscopy identified various structures and anatomical characteristics relevant to the germination process.
Nothofagus antarctica, commonly known as ñirre, is the species with the greatest ecological amplitude in Chile, covering a geographic range of approximately 2,300 km. This species, monoecious and deciduous, adapts to a wide variety of extreme biotypes, reaching heights ranging from 60 cm to 25 m; it is also a reservoir of non-timber forest products, with applications in ornamental, edible and medicinal uses, in addition to offering various environmental services. Despite its versatility, it has a low dispersal capacity, and its propagation is predominantly asexual. The objective of this research is to identify an effective method for the sexual propagation of N. antarctica seeds, as well as to describe the morphoanatomical changes that occur during the germination process. For this purpose, two germination experiments were carried out, in which both germination percentage and germination speed were evaluated. The first experiment consisted of scarification with sulfuric acid between 0 and 20 minutes, together with cold stratification between 30 and 100 days. In the second experiment, seeds were washed with water at temperatures of 25 °C and 50 °C, and gibberellic acid (AG3) was applied at different concentrations. The results showed that there were no significant differences in germination percentages; however, it was observed that longer exposure to cold increased the germination speed index, while washing seeds with water at 50 °C slowed the germination speed. In addition, seed growth was asynchronous, and scanning electron microscopy identified various structures and anatomical characteristics relevant to the germination process.
Description
Tesis presentada para optar al título de Ingeniero/a Agrónomo/a.
Keywords
Nothofagus, Germinación, Propagación de las plantas