Figure 6.

¹⁰⁸Cd uptake by roots grown in a split-root system. Plants were precultured as described in Figure 1 for 5 weeks, and then the root system of each plant was divided into two approximately equal parts, each of which was transferred to a different container in complete nutrient solution. The plant was left undisturbed for 1 week, and then the roots were immersed in either complete (+NO₃⁻) or NO₃⁻-free (−NO₃⁻) nutrient solution containing either 20 μm CdCl₂ or 20 μm ¹⁰⁸CdCl₂ for 1 h, as indicated. A, Schematic representation of the split-root experimental protocol. B, GUS staining of the roots of pNRT1.1::NRT1.1-GUS transgenic plants. C, ¹⁰⁸Cd uptake rates by Col-0, chl1.5, and nrt1.1-1 roots. The bars represent the sd (n = 5 biological replicates). Asterisks indicate significant differences compared with Col-0 plants (***P < 0.001; two-tailed Student’s t test). FW, Fresh weight.