Is there a metabolic link between H⁺excretion and ferric reduction by roots of Fe‐deficient plants?—a viewpoint

A metabolic pathway is proposed which connects the two main ‘Fe‐efficiency’ reactions of dicotyledonous plants, proton excretion, and ferric chelate reduction. The pathway goes as follows: proton excretion is coupled to citrate anion accumulation; citrate is isomerized to isocitrate; isocitrate reduces NADP; NADPH donates electrons directly or indirectly to the ‘Turbo’ reductase system in the plasma membrane of the root epidermal cells.