Seed priming mitigates high salinity impact on germination of bread wheat (Triticum aestivum L.) by improving carbohydrate and protein mobilization

Salinity is increasingly considered as a major environmental issue, which threatens agricultural production by decreasing yield traits of crops. Seed priming is a useful and cost-effective technique to alleviate the negative effects of salinity and to enable a fast and uniform germination. In this context, we quantified the effects of priming with gibberellic acid (GP), calcium chloride (CP), and mannitol (MP) on seed germination of three bread wheat cultivars and investigated their response when grown at high salinity conditions (200 mM NaCl). Salt exposure strongly repressed seed imbibition and germination potential and extended germination time, whereas priming enhanced uniformity and seed vigor. Seed preconditioning alleviated the germination disruption caused by salt stress to varying degrees. Priming mitigating effect was agent-dependent with regard to water status (CP and MP), ionic imbalance (CP), and seed reserve mobilization (GP). Na+ accumulation in seedling tissues significantly impaired carbohydrate and protein mobilization by inhibiting amylase and proteases activities but had lesser effects on primed seeds. CP attenuated ionic imbalance by limiting sodium accumulation. Gibberellic acid was the most effective priming treatment for promoting the germination of wheat seeds under salt stress. Moreover, genotypic differences in wheat response to salinity stress were observed between varieties used in this study. Ardito, the oldest variety, seems to tolerate better salinity in priming-free conditions; Aubusson resulted the most salt-sensitive cultivar but showed a high germination recovery under priming conditions; Bologna showed an intermediate behavior.

Automated summary

Salinity is a major environmental issue that negatively affects agricultural production. Seed priming with gibberellic acid, calcium chloride, and mannitol can alleviate the adverse effects of salinity and promote seed germination in bread wheat cultivars. Priming treatments had varying effects on water status, ionic balance, and seed reserve mobilization. Sodium accumulation impaired carbohydrate and protein mobilization in seedlings, but had lesser effects on primed seeds. Calcium chloride was effective at limiting sodium accumulation and gibberellic acid was the most effective priming treatment for promoting germination under salt stress. Genotypic differences in wheat response to salinity stress were also observed, with Ardito showing better tolerance and Aubusson showing high germination recovery under priming conditions.