Effect of cadmium on H+ATPase activity of plasma membrane vesicles isolated from roots of different S-supplied maize (Zea mays L.) plants

The plasma membrane of root cells constitutes the major membrane barrier between cytoplasm and soil environment and is the first functional site of contact of the root with any ion, so this may have a number of consequences for heavy metal toxicity. In fact, plasma membrane contains potential metal-sensitive enzyme systems, like H(+)ATPase. It is well known the role of sulphide in plant responses to Cd and it gives the rationale for studying the interactions between sulphur availability and Cd-exposure. In this work we report on the alteration of non-protein thiols levels and on plasma membrane H(+)ATPase activity, by measuring changes in its phosphohydrolytic activity and H+ pumping capacity, in Cd exposed and differently S-supplied maize roots. (c) 2005 Elsevier Ireland Ltd All rights reserved.