Figure 3. Dynamics of fungal root colonization and plant growth under different nutritional conditions.

Plants inoculated or not with R. irregularis were supplied with water (blue), basic nutrient solution (red), 5 mM KH₂PO₄ (green), or with a combination of 5 mM KH₂PO₄ and basic nutrient solution (purple). Samples were harvested at the indicated time points to determine root colonization (a), shoot fresh weight (b,c), and mycorrhizal growth response (MGR; (d)). MGR is defined as the ratio of the shoot weight of mycorrhizal versus non-mycorrhizal control plants. Values are the mean of three biological replicates. Error bars represent standard deviations.