Effect of calcium and light on the germination of Urochondra setulosa under different salts.

Urochondra setulosa (Trin.) C.E. Hubbard is a coastal halophytic grass thriving on the coastal dunes along the Pakistani seashore. This grass could be useful in coastal sand dune stabilization using seawater irrigation. The purpose of this investigation was to test the hypothesis that Ca(2+) (0.0, 2.5, 5.0, 10.0 and 50.0 mmol/L) alleviates the adverse effects of KCl, MgSO(4), NaCl and Na(2)SO(4) at 0, 200, 400, 600, 800 and 1000 mmol/L on the germination of Urochondra setulosa. Seed germination was inhibited with increase in salt concentration with few seeds germinated at and above 400 mmol/L concentration. No seed germinated in any of the KCl treatments. Inclusion of CaCl(2) substantially alleviated the inhibitory effects of all salts. Germination was higher under photoperiod in comparison to those seeds germinated under complete darkness. Among the CaCl(2) concentrations used, 10 mmol/L was most effective in alleviating salinity effects and allowing few seeds to germinate at 1000 mmol/L KCl, MgSO(4), NaCl and Na(2)SO(4) solution.