Accelerated aging in Colobanthus quitensis seeds: understanding stress responses in an extremophile species.

Abstract

Main conclusion: Accelerated aging effectively evaluates Colobanthus quitensis seed quality, revealing that deterioration reduces germination performance and total sugars, while increasing indole-3-acetic acid levels, indicating physiological decline. Seed deterioration affects all species and presents a major challenge for the management of germplasm banks. Colobanthus quitensis is one of the two extremophile vascular species native to Antarctica and is recognized for its biotechnological potential in environmental stress studies and as a bioindicator of climate change. However, the manifestation of physiological deterioration in the seeds of this species remains unknown. This study aimed to analyze the physiological changes occurring in C. quitensis seeds during the deterioration process. To achieve this, the accelerated aging method was applied to evaluate variations in germination and various biochemical indicators between aged and non-aged seeds. The results showed that the germination percentage, mean germination time, time required to reach 50% germination, and germination speed coefficient significantly decreased with seed deterioration. However, once the seed coat is broken, germination may be enhanced. Additionally, total sugar content decreased significantly with aging, while indole-3-acetic acid content increased. In conclusion, accelerated aging leads to a reduction in germination indices, and both total sugar and indole-3-acetic acid contents may serve as markers of physiological deterioration in C. quitensis and other species characterized by small seeds, seed dormancy, and hard seed coats.