Studies on Alkaline Band Formation in Chara corallina: Ameliorating Effect of Ca2+ on Inhibition Induced by Osmotic Shock

Abstract

Although the decrease in cell turgor by application of sorbitol to the external medium did not inhibit the alkaline band formation in Chara corallina, recovery of normal turgor severely inhibited it. Alkaline-loading analysis suggested that the inhibition of alkaline band formation was caused by inhibition of HCO3- influx but not that of OH- efflux. In the presence of 10 mM CaCl2, the capacity of alkaline band formation was maintained during osmotic treatment. Cells could not form alkaline bands, when plasmolysis was induced by application of sorbitol at a higher concentration. Addition of 10 mM CaCl2 could ameliorate the inhibition caused by plasmolyis.