A transplasmamembrane electron transport system in maize roots.

Ferricyanide is actively reduced by intact maize (Zea mays L., var XL 342) roots. This reduction is salt and temperature dependent, is stimulated by fusicoccin, and is accompanied by decrease of external pH. In anaerobic conditions, ferricyanide partially restores fusicoccin-induced proton extrusion. A salt-, temperature-, and pH-dependent cyanide-insensitive NADH-ferricyanide oxidoreductase activity can be demonstrated in microsomes isolated from the same plant tissue. This evidence supports the hypothesis, as proposed by Craig and Crane (1982 Plant Physiol 67: S-558, S-835), that the ferricyanide reduction is carried out by a transmembrane NADH dehydrogenase.