Cambios bioquímicos en Araucaria angustifolia (Araucariaceae) durante el almacenamiento cigótico embrionario.
Fecha
Autores
Garcia, Cristhyane
Medeiros Coelho, Cileide Maria
Maraschin, Marcelo
Farias Soares, Francine Lunardi
Guerra, Miguel Pedro
Wilhelm Filho, Danilo
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Universidad de Costa Rica
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Descripción
Especies reactivas del oxígeno (ROS) están presentes en todos los organismos aeróbicos, pero los procesos de deterioro de semillas pueden aumentar su producción. El estrés oxidativo causado por el aumento de ROS endógeno puede causar un daño irreparable a las células, que conduce a la pérdida de viabilidad de la semilla. Teniendo en cuenta que la enzima superóxido dismutasa (SOD) compone el primer mecanismo de defensa antioxidante enzimática, este estudio tuvo por objetivo evaluar los embriones cigóticos de semillas recalcitrantes de Araucaria angustifolia durante el almacenamiento los cambios en la actividad de SOD. Además, algunas alteraciones importantes derivadas de estrés oxidativo, como la peroxidación lipídica y los cambios en las proteínas y la integridad del DNA también se evaluaron. Aproximadamente 7 000 semillas fueron cosechadas de una población en el sur de Brasil y almacenadas durante 180 días en el laboratorio (L), refrigeración (R) y congelamiento (F). El análisis de la peroxidación de lípidos a través de los niveles de TBARS, actividad de la SOD, perfil proteico por separación electroforética e integridad del DNA genómico se realizaron a los 0, 60, 120 y 180 días de almacenamiento. Los resultados revelaron un aumento de la peroxidación lipídica y de la actividad de la SOD, especialmente durante el almacenamiento en L, una condición en la que hubo una extensa degradación de las proteínas. Algunas proteínas (45, 32 y 31 kDa) se expresaron sólo en embriones almacenados en condiciones R y F. No se observaron daños en la integridad del DNA nuclear para el período de almacenamiento de semillas en condiciones R y F. Las muestras F mantienen las características bioquímicas analizadas durante todo el período de almacenamiento, con la excepción del perfil de proteínas. Sin embargo, tales cambios son limitantes para el mantenimiento de la viabilidad de la semilla. En conclusión, el almacenamiento en refrigeración puede ser indicado para retrasar las alteraciones metabólicas que se producen cuando las semillas están expuestas a condiciones de ambiente natural después de la cosecha, que extiende el período de conservación de las semillas de A. angustifolia.
Reactive oxygen species (ROS) are present in all aerobic organisms, but the seed deterioration processes can increase its production. Oxidative stress caused by higher endogenous ROS may cause irreparable damage to cells, leading to the loss of seed viability. Considering that the enzyme superoxide dismutase (SOD) composes the first enzymatic antioxidant defense mechanism, this study aimed to evaluate zygotic embryos of Araucaria angustifolia recalcitrant seeds during storage regarding changes in SOD activity. Besides, some of the major alterations resulting from oxidative stress, e.g., lipid peroxidation and changes in proteins and DNA integrity were also measured. Approximately, 7 000 seeds were harvested from a population in Southern Brazil and stored for 180 days under laboratory (L, laboratory temperature), refrigeration (R, 5 ± 1 °C) and freezing (F, -18 ± 1 °C) conditions. The analysis of lipid peroxidation through TBARS levels, SOD activity, protein profile by electrophoretic separation, and integrity of genomic DNA were performed at 0, 60, 120, and 180 days of storage. The results revealed an increase in lipid peroxidation and SOD activity, especially during the L storage, a condition in which there was an extensive degradation of proteins. Some proteins (i.e., 45, 32, and 31 kDa) were expressed only in embryos stored under R and F conditions. No damage was observed in the nuclear DNA integrity for the evaluated period of seed storage at R and F conditions. The F samples maintained the biochemical traits of interest throughout the storage period, with the exception of the protein profile. However, such changes are limiting for the maintenance of seed viability. In conclusion, R storage can be indicated to delay the metabolic feature alterations that occur when seeds are exposed to conditions of natural ambient after harvest, extending the conservation period of A. angustifolia seeds.
Reactive oxygen species (ROS) are present in all aerobic organisms, but the seed deterioration processes can increase its production. Oxidative stress caused by higher endogenous ROS may cause irreparable damage to cells, leading to the loss of seed viability. Considering that the enzyme superoxide dismutase (SOD) composes the first enzymatic antioxidant defense mechanism, this study aimed to evaluate zygotic embryos of Araucaria angustifolia recalcitrant seeds during storage regarding changes in SOD activity. Besides, some of the major alterations resulting from oxidative stress, e.g., lipid peroxidation and changes in proteins and DNA integrity were also measured. Approximately, 7 000 seeds were harvested from a population in Southern Brazil and stored for 180 days under laboratory (L, laboratory temperature), refrigeration (R, 5 ± 1 °C) and freezing (F, -18 ± 1 °C) conditions. The analysis of lipid peroxidation through TBARS levels, SOD activity, protein profile by electrophoretic separation, and integrity of genomic DNA were performed at 0, 60, 120, and 180 days of storage. The results revealed an increase in lipid peroxidation and SOD activity, especially during the L storage, a condition in which there was an extensive degradation of proteins. Some proteins (i.e., 45, 32, and 31 kDa) were expressed only in embryos stored under R and F conditions. No damage was observed in the nuclear DNA integrity for the evaluated period of seed storage at R and F conditions. The F samples maintained the biochemical traits of interest throughout the storage period, with the exception of the protein profile. However, such changes are limiting for the maintenance of seed viability. In conclusion, R storage can be indicated to delay the metabolic feature alterations that occur when seeds are exposed to conditions of natural ambient after harvest, extending the conservation period of A. angustifolia seeds.
Palabras clave
Piño Brasileño, semillas recalcitrantes, deterioro de las semillas, estrés oxidativo, superóxido dismutasa, Brazilian pine, recalcitrant seeds, seed deterioration, oxidative stress, superoxide dismutase