Effects of different salts and mannitol on seed imbibition, germination and ion content of Crithmum maritimum L. (Apiaceae)

Saline habitats contain various salt types that differently affect seed germination and subsequent seedling establishment. Most studies on the germination process have been carried out using NaCl, which may limit the accuracy of the conclusions drawn, especially regarding the plant behaviour under field conditions. We compare here the impact of iso-osmotic solutions of four salts (NaCl, Na2SO4, MgCl2 and MgSO4) and mannitol on seed imbibition, germination, germination recovery, viability and seedling ion relations of the halophyte Crithmum maritimum L. Seed imbibition percentage declined as osmotic potentials decreased. MgCl2 and NaCl were the most and less adverse salt on the germination, respectively. As for seed germination and viability, K+, Ca2+, NO3- and PO43- contents within seedlings appeared to be salt-diminished. This was associated with higher ion (K+ and Ca2+) leakage. In conclusion, both osmotic and toxic salt components impaired seed germination. This may be related to the effects of different salts on ion content, seed imbibition, and nutrient leakage through membranes.