Uptake and translocation of arsenate and arsenite in sorghum plants (Sorghum biocolor)

ENVR 47

Nazmul Haque, mnhaque@utep.edu1, Jorge L. Gardea-Torresdey, jgardea@utep.edu2, Alejandro Martinez, amartinez29@utep.edu2, and Ntebogeng S. Mokgalaka, nsmokgalaka@utep.edu2. (1) Environmental Science and Engineering, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, (2) Department of Chemistry, University of Texas at El Paso, 500 W University Avenue, El Paso, TX 79968
In this research, the uptake of As(V) (as arsenate) and As(III) (as arsenite) by sorghum plants (Sorghum Biocolor) was studied. In addition, the effects of arsenic on plant growth and nutrient uptake were also investigated. The plants were grown in hydroponics media containing different concentrations of As(III) (0.5 and 1 mg/L) and As(V) (1, 5 and 10 mg/L). As(V) concentrations of up to 10 mg/L had no effects on the morphology and growth of the plants, whereas 90% of the plants grown in 5 mg/L As(III) did not survive. This clearly demonstrates that the uptake of As was influenced by its concentration in the growth medium and the speciation of this toxic metalloid. The uptake of As(V) (2,400, 810 and 300 mg/kg for roots, stems and leaves, respectively) was 30 times more than As(III) which is more toxic than As(V). The roots and shoots elongation of plants grown in 1 mg/L As(III) were significantly smaller than the elongation of plants grown in 1 mg/L As(V). Plants grown in As(III) absorbed micro and macro nutrients to a lesser extent as compared to those grown in the As(V) media. The significant amount of As concentrated in the plants indicate that sorghum biocolor, a very environmental friendly and available plant, could be a potential hyperaccumulator of As for application in phytoremediation of As-contaminated soil and water.