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. [ABSTRACT FROM AUTHOR]

Testes de vigor de sementes são usados para estimar sua qualidade. Um dos mais utilizados é o teste de envelhecimento acelerado (EA). O objetivo do presente estudo foi estudar as alterações bioquímicas provocadas nas sementes e determinar seu status de germinação após o EA. Seis genótipos de cártamo foram testados a 43 °C e 45 °C por 0, 48, 72, 96 e 120 h, e a porcentagem de germinação (PG), o tempo médio de germinação (TMG) e a porcentagem normal de plântulas (PNP) foram avaliados para determinar as reações de envelhecimento dos genótipos. Durante o EA a 45 °C, as sementes perderam rapidamente a capacidade de germinação após 48 h; após 120 h, as sementes perderam a viabilidade, mantendo-se, porém, ainda viáveis a 43 °C. Dois genótipos que envelheceram mais (Linas e Olas) e menos (Bayer-6 e Bayer-12) foram escolhidos para examinar as alterações bioquímicas durante o EA a 43 °C. Onze análises bioquímicas foram realizadas para entender as alterações fisiológicas associadas ao teste. Os teores totais de caratona, xantofila, fenólicos, flavonoides, proteínas solúveis, açúcares solúveis, óleo e malondialdeído foram menores após 120 h, em comparação a 0 h. O teor de açúcares redutores e de ácidos graxos livres aumentou nos genótipos menos e mais envelhecidos. No entanto, o teor total de tocoferol aumentou nos genótipos com menor envelhecimento e diminuiu nos genótipos com maior envelhecimento após 120 h, em comparação a 0 h. Os resultados mostraram que o EA a 43 °C foi adequado para estudar o processo de envelhecimento nas sementes de cártamo. Além disso, compreender as alterações químicas foi útil para elucidar a base fisiológica de envelhecimento das sementes. [ABSTRACT FROM AUTHOR]

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