Fig. 8.

Al concentrations (left column) along a buckwheat adventitious root, and Al contents of the 5 mm root segment cylinders (right column, root cylinders I–V, see Fig. 1) at different distances from the root tip as determined by LA-ICP-MS. The plants were treated with 75 μM AlCl₃ for 24 h in simplified nutrient solution (500 μM CaCl₂, 100 μM K₂SO₄, 8 μM H₃BO₃, pH 4.3). Root tip tissue layers were defined by dividing the root diameter into nine even regions. Data were calibrated by ablation of an agarose–pectin mixture with the same carbon and water contents as buckwheat root tips and defined Al concentrations. The Al signal intensity was normalized using the ¹³C signal intensity and calculated as the mean over the ablated path length of 10 μm and 1 s ablation time. Bars represent means of six ablated cross-section diameters of six different root tips per 5 mm segment. Different letters denote significant statistical differences between root zones/root cylinders (Tukey test P <0.05).