“…The resulting 'proton-motive force' is the sum of an electrical (A$) and of a concentration-dependent (ApH) component. In chloroplasts, ATP hydrolysis [2,4] is coupled to an inward transport of H' (ApH) but a concomitant change of the membrane potential (A*) has not yet been evidenced, contrary to what has been observed in other similar systems, mitochondria or bacterial chromotophores.…”