Effect of mineral nutrients on the uptake of Cr(VI) by maize plants

To determine the potential of maize plants for phytoextraction of chromium (Cr), and the effect that some mineral nutrients have on this process, the uptake of this metal was analyzed in vitro. 12-day-old plants were incubated in nutrient solutions with 200 or 250 mu M potassium chromate and 3 mM supplements of nitrate, phosphate or sulfate. The greatest accumulation of Cr after 48 hours was in plants that were supplemented with nitrate (800 and 350 mg kg(-1) DW for roots and stems, respectively) with bioaccumulation factors of 18 and 7 in the roots and in the foliage, respectively. Moreover, the translocation factor from root to leaves was 0.4 when nitrate was supplemented; thus, the addition of this nutrient is recommended when the crop is to be used for phytoextraction of Cr. Considering the results obtained, the high biomass produced by this crop and the extensive knowledge of agricultural practices for this plant, we believe that maize has the potential to be considered in the phytoextraction of Cr, based on preliminary assays of soil conditions.