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 150μm 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.