Benzylaminopurine‐induced coupling between calmodulin and Ca‐ATPase in wheat root microsomal membranes

The properties of the Ca‐ATPase prepared from roots of wheat seedlings treated with benzylaminopurine were studied. The affinity of the ATPase towards Ca 2+ , plant or erythrocyte calmodulin increased after the hormonal treatment. It seems that in the membrane calmodulin‐bonding sites were induced by benzylaminopurine, contributing to an increased affinity of the ATPase. The lower Ca‐content of the hormone‐treated plants suggests that in vivo the Ca‐ATPase is involved in a Ca‐extrusion process.