Comparative effects of NaCl and sea salt on seed germination of arthrocnemum indicum

Arthrocnemum indicum is a stem succulent perennial halophyte from the family Chenopodiaceae. Experiments on seed germination were carried out using NaCl and sea salt (0, 20, 40, 60, 80 and 100 dS m/sup -1) at alternating temperature regimes (10:20 deg.C, 15:25 deg. C, 20:30 deg. C and 25:35 deg. C) at photo period of 12 h dark: 12 h light and in 24 h dark. Seed germination of A. indicum was substantially delayed and/or prevented with an increase in NaCl and sea salt concentrations. Only few seeds germinated above 20 dS m/sup -1/. Sodium chloride and sea salt differ in their effect on seed germination at all temperature regimes. NaCl prevented more seeds from germination in comparison to sea salt. Optimal germination was obtained in non saline control at lower temperature regime whereas warmer temperatures in our experiment inhibited more seeds from germination. Seed germination was not affected either by photo period or dark conditions in non saline control at all temperature regimes. At low NaCl treatments there were significant differences between light and dark germinated seeds at 15:25 deg. C and 20:30 deg. C. Seed germination in sea salt was similar in both light and dark conditions except at 20 dS m/sup -1/ at 15:25 deg. C. Highest recovery was obtained at cooler temperature regime of 10:20 deg. C while lowest at warmer temperature regime of 25:35 deg. C. Most of the un-germinated seeds were found dead in both salt treatments and their mortality increased with an increase in temperature. (author)