Abstract: Under osmotic stress induced by PEG-6000 (20%), when the roots of wheat（Triticum aestivum L. cv 4185）were treated with low concentration of exogenous Ca2+ at 10-6-10-3 mol·L-1, there were no significant difference in growth of coleoptiles and roots, but the growth was inhibited by exogenous Ca2+ at 10-2 mol·L-1. The treatments for roots with EGTA (1, 5,10 mmol·L-1), LaCl3 (0.5, 1 mmol·L-1) and Verapamil (250, 500 μmol·L-1) inhibited the growth of coleoptiles and roots, which were closely related to the increase of peroxidase (POD) activity. These results showed that under osmotic stress, the wheat was more sensitive to deficiency of Ca2+. The higher exogenous Ca2+ concentration, lower extracellular Ca2+ concentration and blocking Ca2+ transfer would suppress the growth of wheat coleoptiles and roots.

Key words: Wheat, Root, Coleoptile, Drought, Calcium, Osmotic stress