Abstract
Chromium (Cr) is the seve th ost a u da t etal i the earth’s rust a d a important contaminant in environment. On Cr stress, ROS (reactive oxygen species) is produced in many plants, generating oxidative stress leading to cells damage. In response to oxidative stress, plants have developed defense system to scavenge the ROS by enzymatic and non-enzymatic antioxidants. The aim of study to analyzed antioxidative responses of Sorghum bicolor in Indonesia under Cr(III) and Cr(VI) stresses. Experiments used FCRD (factorial completely randomized designs) with three factors (Cr forms, Cr concentrations, and cultivars of Sorghum bicolor). On Cr(VI) stress, ascorbic acid concentration of S. bicolor cv. Badik and SOD (superoksida dismutase) activities increased, APX (ascorbate peroxidase) activities increased in low concentration (1,8 mg/kg) but decreased in high concentration (4,5 mg/kg), and carotenoid concentrations decreased. On Cr(III) stress, SOD activity and antioxidant reducing power of S. bicolor cv. Badik and APX activity of S. bicolor cv. UPCA increased, but APX activity of S. bicolor cv. Badik decreased. Cr(VI) stress induced antioxidative responses of S. bicolor higher than Cr(III) stress. Both cultivar of S. bicolor has similar antioxidative responses under Cr(VI) dan Cr(III) stresses. Overall, antioxidative enzymes stronger than antioxidant compounds in the detoxification of Cr toxicity. The interaction of treatment factors on antioxidative enzymes and antioxidant compounds exert significant influence.
