Assessment of arsenic induced physiological and lipid peroxidation response in two indica rice cultivars

Abstract

Aim: To investigate the potential of sodium arsenite to induce physiological as well as oxidative stress at its low level exposure in tolerant and sensitive indica rice cultivars. Methodology: Rice seeds were surface sterilized using 0.1% HgCl2 for 15 min, followed by washing with distilled water. Twelve days after germination, the seedlings in one tray was kept aside as control and other trays were exposed to 50, 100, 150 and 200 μM of sodium arsenite. After treatment for 24 and 48hr, leaves were harvested and washed with distilled water to estimate the level of lipid peroxidation as well as physiological stress parameters. Results: The oxidative damage increased with corresponding increase in the sodium arsenite concentration in both the succeptible IR-64 and tolerant Nonabokra cultivars, the effect being more prononced in IR-64 than Nonabokra. The status of lipid peroxidation was assessed through quantification of its secondary product malondialdehyde by TBARS assay (P≤0.05). Significant increase in lipid peroxidation levels were observed in all the arsenic exposed groups of rice plants. Interpretation: The detrimental effect of arsenic was reflected as more chlorophyll loss, decrease in water content and significant reduction in the length of root as well as shoot of rice plants. Besides, significant elevated levels of LPO indicated drastic cellular damage in all the arsenic exposed groups of rice plants. Key words: Chlorophyll loss, Indica rice, Lipid peroxidation, Sodium arsenite, Water content