Phytoextraction of Soil Cadmium by Vetiveria zizanioides Dead Shoots.

Abstract

Vetiveria zizanioides, as a perennial herb with high biomass, provides a feasible method for the phytoextraction of cadmium (Cd). In this study, two levels of Cd exposure (18 and 200 mg·kg^-1) were performed to investigate Cd accumulation in Vetiveria zizanioides. The results showed that Cd content in dead shoots reached 1412.35 mg·kg^-1, 5.79 folds higher than that in roots. Cd stress promoted Fe mobility in the soil and increased Fe accumulation in plant. The correlation between Fe and Cd revealed that the competition between Fe and Cd inhibited the metabolic absorption of Cd in Vetiveria zizanioides. Cd stress accelerated shoot senescence and increased stomatal density, suggesting that Cd flowed into dead shoots was mainly motivated through its vessel transport. This study offers a theoretical basis for phytoextraction of high Cd-contaminated soils.