Institutional Repository | Satya Wacana Christian University: Distribusi dan Biokumulasi Krom Heksavalen pada Tanaman Sorgum (Sorghum bicolor (L.) Moench)

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.
Key words: Cr, sorghum, biomass, accumulation, oxidation