Silicon mediates arsenic tolerance in rice (Oryza sativa L.) through lowering of arsenic uptake and improved antioxidant defence system

► Si addition significantly reduces As accumulation in rice. ► Si ameliorated As induced oxidative stress in both the cultivars. ► Si addition enhanced the level of antioxidant enzymes and their isozymes in rice during As(III) stress. ► Si addition reduced As phytotoxicity more significantly in tolerant rice than sensitive rice.