The model predicts effects of varying the expression of transporter genes (individually or in combination) which have yet to be investigated in experiments. For example, our findings indicate that simultaneously overexpressing plasma membrane and tonoplast Naþ/Hþ antiporter genes would lead to improvements in both ionic and osmotic stress tolerance. The results demonstrate the importance of simultaneously modelling the transport of Naþ across both the tonoplast and plasma membrane, a task not undertaken previously.