Interaction between Salinity and Original Habitat during Germination of the Annual Seashore Halophyte Cakile Maritima

Abstract

The impact of salinity (0–400 mM NaCl) on the germination of four Tunisian accessions (Tabarka, Mahdia, Sfax, and Jerba) of the halophyte Cakile maritima was assessed. Moderate salinity (50–150 mM NaCl) slightly inhibited the germination of Sfax, Mahdia, and Jerba seeds, since more than 75% of the sown seeds germinated. Salt adverse impact was more pronounced in Tabarka seeds, which showed significantly less germination capacity, even under salt‐free conditions (40%). Although increasing salinity drastically inhibited the germination in Tabarka, Sfax was the most tolerant accession, especially at 200–300 mM sodium chloride (NaCl). Assessing germination kinetics using a mathematical model indicated that high salinity impaired and delayed the germination process. Such an effect resulted from the combination of osmotic and toxic components, especially at the greatest concentrations (300–400 mM NaCl). These findings point out that the successful establishment of this halophyte at the earliest ontogeny stages is both accession‐ and salt‐dependent.

Keywords:

• Cakile maritima
• germination
• halophyte
• salinity
• variability

ACKNOWLEDGMENTS

Mohamed Ali Ghars is indebted to the French Ministry of Foreign Affairs (French Embassy, Tunis) for an AUF fellowship. The constructive contribution of Professor Claude Grignon (Biochimie et Physiologie moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, Ecole Nationale Supérieure d'Agronomie/Institut National de la Recherche Agronomique, Montpellier, France) is gratefully acknowledged.