Effect of salinity on seed germination, growth and ion content in dimorphic seeds of Salicornia europaea L. (Chenopodiaceae)

The halophyte Salicornia europaea L. is a widely distributed salt-tolerant plant species that produces numerous dimorphic seeds. We studied germination and recovery in dimorphic seeds of Central Asian S. europaea under various salinity conditions. We also tested the effects of various salts on Na(+) and K(+) accumulation during plant development from germination to anthesis under greenhouse conditions. We found good germination (close to control) of large seeds under NaCl between 0.5 and 2%, Na(2)SO(4) and 2NaCl + KCl + CaCl between 0.5 and 3%, and 2Na(2)SO(4) + K(2)SO(4) + MgSO(4) between 0.5 and 5%. For the small seeds, we found stimulating effects of chloride salts (both pure and mixed) under 0.5–1% concentrations, and sulfate salts under 0.5–3%. Both types of seeds showed high germination recovery potential. Salt tolerance limits of the two seed types during germination and at the later stages of development were very similar (4–5%). During plant growth the optimal concentrations of mixed chloride and sulfate salts ranged from 0.5 to 2%. The mechanisms of salt tolerance in the two seed types of S. europaea appear to differ, but complement each other, improving overall adaptation of this species to high salinity.