Tolerance at heat shock in Deschampsia antarctica Desv.: physiologic and metabolomic analysis
Throughout its evolutionary history, the Antarctic biota has always faced low temperatures with surviving the extreme conditions of the Antarctic continent. Deschampsia antarctica Dev. it is one of the most successful colonizers on the continent, morphologically and physiologically adapted to the An...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2020 |
| País: | Chile |
| OAI Identifier: | oai:repositorio.anid.cl:10533/42522 |
| Acceso en línea: | https://hdl.handle.net/10533/42522 |
| Access Level: | acceso abierto |
| Palabra clave: | Ciencias Naturales Ciencias de la Tierra y del Medio Ambiente Bioquímica |
| Sumario: | Throughout its evolutionary history, the Antarctic biota has always faced low temperatures with surviving the extreme conditions of the Antarctic continent. Deschampsia antarctica Dev. it is one of the most successful colonizers on the continent, morphologically and physiologically adapted to the Antarctic climate. However, climate change is advancing at a faster rate in Antarctica than the rest of the planet, registering heat waves with maximums of 18.4 ° C and 20.8 ° C during the summer of 2020, being recorded as the hottest in its history. These abnormal temperatures for the continent can be considered as a thermal shock for Antarctic plants. However, these warmer temperatures have benefited the expansion and size of the populations of D. antarctica in the Antarctic Peninsula. This work evaluates the tolerance to heat shock of D. antarctica cultivated in vitro from a physiological and metabolomic point of view. For this purpose, the lethal temperature 50 (LT50) of the plants in vitro was determined, and two thermal shock conditions of 23 ° C and 35 ° C, and treatment equivalent to LT50, were evaluated in plants exposed daily for 2 hours for seven days. Additionally, post-treatment recovery periods at 35 ° C and LT50 were applied to determine the recovery capacity of D. antarctica. In each treatment, we evaluate the physiological response of the plants by analyzing aerial growth, photosynthetic performance, the integrity of photosynthetic pigments and redox balance. At the same time, the defensive responses of the plants were evaluated by the enzymatic and non-enzymatic antioxidant action, the profile of phenolic compounds and soluble sugars. The results showed that D. antarctica cultivated in vitro tolerates a thermal shock of up to 35 ° C, maintaining its normal physiological, photosynthetic efficiency, chlorophyll content, and redox balance. However, the tolerance mechanisms in D. antarctica are closely related to the severity of heat shock; at 23 ° C, there is a more significant role of carotenoids and antioxidant enzymes such as POD and APX. While at 35 ° C, it exhibits a more significant induction of secondary metabolism, increasing compounds of phenylpropanoid and flavonoid nature, in the same way, the accumulation of soluble sugars D-galactose and sucrose increases. |
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