The Effect of Salt Type and Concentration on the Germination of the Sea Asparagus Sarcocornia neei (Lag.)

Seed germination represents a critical bottleneck for the establishment of halophytic crops under saline conditions. In Sarcocornia neei, a promising biosaline species, previous germination studies have focused almost exclusively on sodium chloride, despite the prevalence of sulfate-dominated salinity in many salt-affected environments. In this study, we evaluated the effects of salt type (NaCl vs. Na2SO4) and salinity level (0, 25, 50, 75 and 100% of sea water salinity) on seed germination of three natural populations from ecologically contrasting environments under controlled conditions. Germination percentage, rate and period and post-stress recovery were quantified. Seed germination responses were strongly site-dependent and differed markedly between salt types. Seeds from the inland saline population exhibited a euhalophytic germination pattern with low germination in distilled water and enhanced germination at moderate NaCl and Na2SO4 concentrations. In contrast, seeds from coastal populations showed the classical decline in germination with increasing salinity but displayed a high capacity for post-stress recovery, particularly under sulfate salinity. These results demonstrate that S. neei harbors substantial intraspecific variation in germination responses to both salt type and concentration, reflecting adaptation to local ionic environments. Our findings underscore the relevance of considering population-level variation when selecting plant material for biosaline agriculture and ecological restoration.