The Accumulation and the Release of Divalent Cations Across Mitochondrial Membranes

Accumulated divalent cations and phosphate (P 1 ) in isolated bean mitochondria are released by conditions which inhibit respiration, including anaerobiosis and KCN, or by conditions which divert conserved energy from divalent cation uptake. These include ATP synthesis, K T transport in the presence of valinomycin, and the presence of the uncouplers, 2,4‐dinitrophenol and oleic acid. The results indicate that plant mitochondria are not permanent deposit sites for divalent cation and P 1 salts but, rather, function as temporary sequestering sites for these ions. It is suggested that mitochondria may play a role in the control of the movement as well as a regulation of the concentrations of these ions within the cell.