COMPARATIVE EFFECTS OF NACL AND SEA SALT ON SEED GERMINATION OF TWO HALOPHYTIC GRASSES UNDER VARIOUS LIGHT AND TEMPERATURE REGIMES

Effect of several concentrations of NaCl or sea salt was studied on seeds germination of two halophytic grasses-an annual (Eragrostis ciliaris) and a perennial (Dichanthium annulatum) in controlled growth chambers maintained at 10:20, 15:25, 20:30 and 25:35 degrees C (12 h dark:light) and 24 h dark photoperiods. Sea salt and NaCl both inhibited seed germination but NaCl prevented more seed from germination. Optimal germination was obtained at temperature regime of 25:35 degrees C for both grasses. Seeds of D. annulatum had similar germination both in light and dark at cooler temperatures in distilled water while addition of salinity in dark inhibited more seed germination compared to light treated seeds. No seeds of E. ciliaris germinated in dark and this positive photoblastic response was associated with temperature irrespective of salinity treatment. All seeds recovered from salts stress when returned to distilled water. Most of the un-germinated seeds were dormant and viable at the end of experiment indicating that they could form a viable seed bank to ensure the continuity of the population in saline habitat.