Hormonal Priming to Increase Germination of Stevia rebaudiana Bertoni Seeds in Saline Environments

Abstract

Hormonal priming has recently emerged as a powerful strategy to increase seed germination and early seedling growth, especially in challenging abiotic stress environments. This study explored the impact of gibberellic acid (GA) and salicylic acid (SA) priming on the germination performance of Stevia rebaudiana seeds under saline conditions. Stevia seeds were either hydroprimed with distilled water (control) or primed with varying concentrations of GA (0.1 and 0.2%) and SA (0.25 and 0.5 mM) and then exposed to salt stress (0 and 80 mM NaCl). The results demonstrated that GA and SA priming significantly enhanced germination rates, reduced mean germination time, and improved the salt tolerance index compared to untreated seeds. Primed seeds showed notable improvements in seedling vigor, including greater shoot and root lengths under salinity stress. The best results were achieved with 0.1% GA and 0.5 mM SA, effectively alleviating the detrimental impact of high salinity on germination. The primed seeds also exhibited reduced electrolyte leakage, signifying improved membrane stability under salt stress. In conclusion, this study presents robust evidence that GA and SA priming is an effective approach for enhancing the germination, salt tolerance index, and early growth of Stevia under saline conditions, offering a practical solution to improve crop establishment in salinity-affected regions.