Figure 1.

Root elongation in response to CaCl₂, MgCl₂, and AlCl₃ in the rooting medium. [CaCl₂] + [MgCl₂] = 1 mm and pH = 4.6. RRL_C is the root length in Al solutions relative to Al-free solutions with similar CaCl₂ and MgCl₂. The data were compiled from six experiments, with each point on the graph based on one to six values. Each of these values was based on the measured lengths of 10 roots, as described in Methods.