The role of calcium ions in freezing injuries of winter oilseed rape leaves. Effects of calcium channel blockers and mimesis by calcium ionophore

Calcium ionophore A23187 allowing for a calcium ion influx from an apoplast to a cytoplasm, mimicked symptoms of the frost-induced injuries in winter oilseed rape leaves, as estimated by the conductivity method. Both calcium ionophore and freezing treatment induced degradation of phosphatidylcholine. On the other hand lanthanum and gadolinum ions as well as verapamil, the inhibitors of calcium ion channels, decreased the degree of the frost-induced injuries. Lanthanum ions prevented the frost-induced degradation of PC. It is proposed that freezing alters the functioning of calcium ion channels which results in calcium ion influx into a cytosol. This in turn may lead to a degradation of cell membranes.