Overcoming seed dormancy and improving germination of Convolvulus persicus, an endangered coastal plant in north of Iran

Convolvulus persicus L. is an endemic endangered species distributed in the coastal regions of the Caspian Sea and the Black Sea that displays limited germination, potentially impacting its ability to regenerate. To gain an understanding of the dormancy status and germination needs of C. persicus, seed characteristics, seed coat permeability and different dormancy-breaking treatments were assessed. The results revealed that C. persicus seed coats are water-impermeable and that both cold and warm stratification were effective in breaking dormancy. Furthermore, GA3 pretreatment with combination of either cold or warm stratification proved successful in releasing dormancy. However, the highest germination percentage and rate as well as seed vigour was achieved by mechanical scarification followed by H2SO4 application and warm stratification. Warm stratification was recognized to be more favourable for overcoming seed dormancy and promoting seedling survival than cold stratification. Notably, the influence of population type on germination capacity was found to be negligible. These findings may facilitate the conservation and collection management of this threatened plant species, which is currently underrepresented in ex situ conservation efforts.