Biochemical changes stimulated by accelerated aging in safflower seeds (Carthamus tinctorius L.)

Seed vigor tests are used to estimate their quality. One of the most commonly used is the accelerated aging test (AA). The aim of the present study was to study the biochemical changes caused in the seeds and to determine their germination status after the AA. Six safflower genotypes were tested at 43 °C and 45 °C for 0, 48, 72, 96 and 120 h, and germination percentage (GP), mean germination time (MGT) and normal seedling percentage (NSP) were evaluated to determine the aging reactions of the genotypes. During the AA at 45 °C, the seeds quickly lost their germination ability after 48 h; after 120 h, the seeds lost their viability, remaining, however, still viable at 43 °C. Two genotypes that aged more (Linas and Olas) and less (Bayer-6 and Bayer-12) were chosen to examine the biochemical changes during the AA at 43 °C. Eleven biochemical analysis were performed to understand physiological changes associated with the test. Total caratone, xanthophyll, phenolics, flavonoid, soluble protein, soluble sugars, oil and malondialdehyde contents were lower after 120 h, compared to 0 h. Reducing sugars and free fatty acids contents increased in the least and most aging genotypes. However, the total tocopherol content increased in the least aging genotypes and decreased in the most aging genotypes after 120 h, compared to 0 h. The results showed that the AA at 43 °C was suitable to study the aging process in the safflower seeds. Besides, understanding the chemical changes was useful to elucidate the physiological basis of seed aging.