Potassium induced suppression of magnesium uptake and translocation is limited in oat (Avena sativa L.)

The main cause of magnesium (Mg 2+ ) deficiency in plants is its competition with potassium (K + ). Besides uptake antagonism, previous studies also suggested that high [K + ] inhibits root‐shoot translocation of Mg 2+ . In this study on oat, root elemental analysis revealed an evident but, with further increasing K + /Mg 2+ ratio, limited suppression of Mg 2+ uptake. In contrast, shoot [Mg 2+ ] showed little or no reduction. This indicated a translocation synergism, as the suppression of the root [Mg 2+ ] by K + was counterbalanced. Oat thus provides new insights and raises new questions about the interactions of K + /Mg 2+ , in particular on the role of specific Mg 2+ transporters. A better understanding of this interaction may help to counter the worldwide Mg deficiency more effectively.