Pathways of cadmium fluxes in the root of the halophyte Suaeda salsa

Halophyte plants offer a greater potential for phytoremediation research for reducing the levels of toxic metals from saline soils than salt sensitive plants. Using the scanning ion-selective electrode technique, we analyzed the pattern and rate of Cd 2+ fluxes at different regions of the root apex of Suaeda salsa. The Cd 2+ influx in the rhizosphere was greatest near the root tip (within 150 μm of the tip). The results indicated that Cd 2+ influx into roots was significantly suppressed by the pre-treatment or in the presence of two kinds of Ca 2+ channel blockers; LaCl 3 and verapamil. The Cd 2+ influx was also reduced by N-ethylmaleimide, a thiol blocker. Cd content determination and labeling of Cd using fluorescent dye support our conclusion. The results of this study provide a more stable theoretical basis for the phytoremediation of Cd contamination in saline soils of coastal zones. ► We analyzed the pattern and rate of Cd 2+ fluxes at the root apex of Suaeda salsa. ► Cd 2+ influx was greatest near the root tip (within 150 μm of the tip). ► Cd 2+ influx into roots was significantly suppressed by the Ca 2+ channel blockers. ► Cd 2+ influx was reduced by N-ethylmaleimide, a thiol blocker. ► Cd content determination and labeling using fluorescent dye support our conclusion.