Abstract
Long term use of NPK fertilizer in the soil could caused chromium (Cr) accumulation in root, stem, and leaf of plant. Toxicity of Cr was depended on species and concentration of Cr. Cr(III) and Cr(VI) were more stable than Cr(II), Cr(IV), and Cr(V) in the environment and both could caused reduction in plant biomass. Cr(III) and Cr(VI) could also triggered formation of H2O2. The aims of this research were (i) to study the growth of Sorghum bicolor (L.) which contaminated with Cr(III) and Cr(VI), (ii) to know the distribution and bioaccumulation of Cr(VI) in sorghum, and (iii) to study the biotransformation process of Cr(III). It were hypothesized that growth of sorghum would be different among sorghum contaminated with Cr(III) and Cr(VI). Accumulated Cr(VI) would different in root, stem and leaf. Accumulated Cr(VI) in every varieties would different because of the different growth characteristics. Instead of reduction from Cr(VI) to Cr(III), Cr(III) could be transformed into Cr(VI). The research was set in a green house for 30 days using randomized factorial design with 3 factors, i.e. variety of sorghum (Badik and UPCA), species of Cr (Cr(III) and Cr(VI)), and concentration of Cr (0, 1.8, 4.5, and 13.6 mg kg-1). Measured parameters were biomass of sorghum, concentrations of Cr in root, stem and leaf, and in the medium, and concentration of H2O2. It can be concluded that species and concentration of Cr reduced biomass of root, stem, and leaf both of Badik and UPCA. Highest concentration of Cr(VI) was found in the root. Badik accumulated Cr higher than UPCA. Cr(III) was oxidized into Cr(VI) both of Badik and UPCA because of H2O2 action.
