Hi, Cristina, you can use H+-ATPase inhibitors like erythrosin B, diethyl stilbestrol, and vanadate DCCD, As well as protonophores (carbonylcyanide-m-chlorophenylhydrazone and 2,4-dinitrophenol). However, please, consider that there are many different sites of proton gradients in root cells, and proton gradients are different in different cell layers, different root zones etc. You should also consider patetrns of H+-ATpase expression: it located mainly in the outer cell layers.

So, try to choose lowest concentration to avoid not-specific effect and consider sites of proton gradient formation.

Good luck! .

If you wish to more directly inhibit the ATPase itself, then I agree with Taras that vanadate is a good choice. A protonophore like CCCP will collapse the proton gradient, affecting the proton gradient created by the H+-ATPase, but not necessarily the action of the ATPase itself. With two inhibitors influencing two slight different aspects of plasma membrane transport activity, you have tools which can provide some more precise mechanistic information on which to base your conclusions.

Thank you very much for your suggestions. I am planning to use sodium orthovanadate 0.5mM. Does that make any sense?