Figure 1. Exogenous phosphate and nitrate inhibit root colonization by Rhizophagus irregularis.

Plants inoculated with Rhizophagus irregularis were watered with the basic nutrient solution, additionally supplemented with the indicated nutrient concentrations. The first column to the left in each graph corresponds to the concentration in the basic nutrient solution, except for KH₂PO₄ (see Table S2); the other columns represent elevated nutrient levels as indicated. Columns represent the average of four replicate plants with standard deviations.