Kinetics of iron absorption by excised rice roots

Abstract

Studies on the rate of iron absorption by excised rice roots from solutions of different concentrations of FeSO₄ showed the presence of two patterns, one in the low (0.005–0.5 mM) and the other in the high (1–30 mM) concentration range. The presence of CaSO₄ or MnSO₄ at 0.5 mM enhanced Fe⁺⁺ absorption in the low concentration range, while CaSO₄ at 10 mM inhibited Fe absorption in the high concentration range in a competitive manner. Fe⁺⁺ absorption at both low and high concentrations was sensitive to metabolic inhibitors. The isotherm for Fe⁺⁺ absorption at O° exhibited an initial absorption shoulder in both low and high concentrations and was suggestive of a latent ion-transport capacity for Fe⁺⁺ in rice roots.