CHROMIUM HEAVY METAL PHYTOTOXICITY INDUCED PHYSIOLOGICAL AND BIOCHEMICAL CHANGES IN SORGHUM SEEDLINGS GROWN UNDER IN VITRO

Chromium is a heavy metal; this element is considered as an environmental hazard. Toxicity effects of chromium on growth and development of plants including inhibition of germination process decrease of growth and biomass of plant. The present study was focused to examine the effects on physiological and biochemical parameter of the Sorghum under chromium (Cr) treatment. The shoot and root lengths of Sorghum seedlings decreased gradually with increasing the Chromium concentrations (0, 25, 50, 75and 100 mg/l) in MS medium. The growth rate was declined to 15.3 % and 18.8 % in root and shoot length respectively compared to control. The seedling biomass varied from 88% to 94.64% in tissues compared to the control at 100 mg/Cr. Both SOD and CAT activities were increased up to 100 mg/Cr concentration. POD activity was increased up to 75mg/l and thereafter it was declined with further increase the Cr concentration. Total soluble protein content was increased significantly with increasing the concentrations of Cr in MS medium, compare to the control. The present results suggested that Sorghum is a novel Cr hyperaccumulator and able to tolerate with Chromium induced toxicity by activation of antioxidative defense mechanisms.