Occurrence of interactions between individual Sr2+- and Ca2+-effects on maize root and shoot growth and Sr2+, Ca2+ and Mg2+ contents, and membrane potential: Consequences on predicting Sr2+-impact

Most of the time the individual effects of Sr2+ and Ca2+ were not additive, as these two ions clearly interacted with each other to jointly affect the plant physiology. In spite of these interactions, both [Sr2+]ext or [Sr2+]ext/[Ca2+]ext ratio values seemed to enable a correct prediction of the Sr2+-effects on the plant. However using the [Sr2+]ext/[Ca2+]ext ratio improved significantly the adequacy of prediction compared to the use of [Sr2+]ext alone, as it increased up to 25% the proportion of variability accounted for by the model.