Study the Germination Characteristics of Black Seed (Nigella sativa L.) under Drought Stress Condition in Different Salicylic Acid Levels

Salicylic acid is one of the phenol groups that play an important role in abiotic stress tolerance. This study evaluated germination characteristics of black seed (Nigella sativa L.) under six levels of priming with salicylic acid (0, 0.1, 0.5, 1, 2 and 4 mM) and five levels of water potential (0, -5, -10, -15 and -20 bar) using a 5×6 factorial experiment based on a completely randomized design with three replications. The results showed that the simple and interaction effects of water potential and salicylic acid were significant on germination percentage, radicle and plumule lengths, radicle and plumule weights, radicle/plumule dry weight ratio and consumed endosperm weight. With decreasing water potential, germination percentage, germination rate, radicle and plumule lengths, radicle and plumule weights and consumed endosperm weight of black seed were decreased and 50% germination time and mean germination time were increased. The highest and the lowest amounts of germination percentage were obtained in control and -20 bar by 81 and 15 percentage, respectively. Maximum amount of germination percentage, radicle and plumule lengths, radicle and plumule weights and consumed endosperm weight were achieved in 1 mM salicylic acid concentration. Also, the minimum of 50% germination time and mean germination time were observed in 1 mM salicylic acid concentration. In control, pretreatment with salicylic acid didn't increase the germination characteristics of black seed, but in stress conditions it improved these traits. Therefore, it seems that pretreatment of black seed with salicylic acid could be improved germination characteristics in drought conditions and increase black seed drought resistance to water stress at germination stage