Respuestas fotosintéticas a la sequía en plantas de bofedal en Los Andes de Chile Central: Nativas vs. Exóticas.
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Date
2024
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Universidad de Concepción
Abstract
Uno de los factores ambientales más restrictivos para las plantas es la sequía, la cual se define como un periodo de tiempo anormalmente seco y prolongado que puede provocar un grave desequilibrio hidrológico. Las plantas pueden diferir en su capacidad de resistir condiciones de sequía. Dentro de las respuestas a la sequía se encuentra el cierre estomático, el cual podría reducir algunos procesos vitales, tales como la fotosíntesis. Por ello, parámetros como la tasa fotosintética, conductancia estomática y la eficiencia fotoquímica máxima de fotosistema II permitirían evaluar los efectos de la sequía en las plantas.
La vegetación que crece en condiciones de abundante agua se puede clasificar como azonal. Dentro de este tipo de vegetación se encuentran los bofedales, los cuales se desarrollan cerca de los límites hidrológicos y altitudinales para la vida vegetal. Los bofedales altoandinos en Chile Central se encuentran expuestos a condiciones ambientales adversas tales como las bajas temperaturas. Estas condiciones podrían ser una barrera para las invasiones de plantas. Sin embargo, el aumento de temperaturas asociado al cambio climático podría explicar el establecimiento de plantas introducidas en ambientes de alta montaña.
Las especies vegetales exóticas invasoras serían exitosas en ambientes caracterizados por una alta disponibilidad de los recursos. En condiciones de sequía, se ha descrito que especies de plantas invasoras presentan un menor crecimiento en comparación a especies nativas. Dado que el éxito de las especies de plantas invasoras es dependiente de una alta disponibilidad de recursos, se espera que las especies exóticas invasoras en bofedales altoandinos de Chile central sean menos resistentes a la sequía en comparación a especies vegetales nativas de estos ecosistemas.
El objetivo del presente estudio fue determinar la resistencia a condiciones de sequía de plantas nativas y exóticas de un bofedal altoandino de Chile central. Para evaluar esto, se determinó la tasa fotosintética máxima, conductancia estomática y la eficiencia fotoquímica máxima del fotosistema II en plantas sometidas a un tratamiento de sequía. Posteriormente, los resultados de cada variable fisiológica fueron comparados de acuerdo a su origen y se concluyó que no existían diferencias en plantas de origen nativo y exótico de un bofedal en los andes de Chile central.
One of the most restrictive environmental factors for plants is drought, which is defined as an abnormally dry and prolonged period of time that can cause a serious hydrological imbalance. Plants may differ in their ability to withstand drought conditions. Among the responses to drought is stomatal closure, which could reduce some vital processes, such as photosynthesis. Therefore, parameters such as photosynthetic rate, stomatal conductance and maximum photochemical efficiency of photosystem II would allow the evaluation of the effects of drought on plants. Vegetation that grows in conditions of abundant water can be classified as azonal. Within this type of vegetation are the bofedales, which develop near the hydrological and altitudinal limits for plant life. The high Andean bofedales in Central Chile are exposed to adverse environmental conditions such as low temperatures. These conditions could be a barrier to plant invasions. However, the increase in temperatures associated with climate change could explain the establishment of introduced plants in high mountain environments. Invasive exotic plant species would be successful in environments characterized by high resource availability. In drought conditions, invasive plant species have been described to have lower growth compared to native species. Since the success of invasive plant species is dependent on high resource availability, it is expected that invasive exotic species in high Andean bofedales of central Chile are less resistant to drought compared to native plant species of these ecosystems. The objective of the present study was to determine the resistance to drought conditions of native and exotic plants of a high Andean bofedale in central Chile. To evaluate this, the maximum photosynthetic rate, stomatal conductance and maximum photochemical efficiency of photosystem II were determined in plants subjected to a drought treatment. Subsequently, the results of each physiological variable were compared according to their origin and it was concluded that there were no differences in plants of native and exotic origin from a bofedale in the Andes of central Chile.
One of the most restrictive environmental factors for plants is drought, which is defined as an abnormally dry and prolonged period of time that can cause a serious hydrological imbalance. Plants may differ in their ability to withstand drought conditions. Among the responses to drought is stomatal closure, which could reduce some vital processes, such as photosynthesis. Therefore, parameters such as photosynthetic rate, stomatal conductance and maximum photochemical efficiency of photosystem II would allow the evaluation of the effects of drought on plants. Vegetation that grows in conditions of abundant water can be classified as azonal. Within this type of vegetation are the bofedales, which develop near the hydrological and altitudinal limits for plant life. The high Andean bofedales in Central Chile are exposed to adverse environmental conditions such as low temperatures. These conditions could be a barrier to plant invasions. However, the increase in temperatures associated with climate change could explain the establishment of introduced plants in high mountain environments. Invasive exotic plant species would be successful in environments characterized by high resource availability. In drought conditions, invasive plant species have been described to have lower growth compared to native species. Since the success of invasive plant species is dependent on high resource availability, it is expected that invasive exotic species in high Andean bofedales of central Chile are less resistant to drought compared to native plant species of these ecosystems. The objective of the present study was to determine the resistance to drought conditions of native and exotic plants of a high Andean bofedale in central Chile. To evaluate this, the maximum photosynthetic rate, stomatal conductance and maximum photochemical efficiency of photosystem II were determined in plants subjected to a drought treatment. Subsequently, the results of each physiological variable were compared according to their origin and it was concluded that there were no differences in plants of native and exotic origin from a bofedale in the Andes of central Chile.
Description
Tesis presentada para optar al título profesional de Bióloga
Keywords
Fotosíntesis, Humedales América del Sur, Plantas endémicas, Plantas exóticas