Comparative evaluation of cadmium toxicity effects on growth, photosynthetic and oxidative stress parameters in various genotypes of Indica rice (Oryza Sativa L.) seedlings

In hydroponics, experiments were performed to examine plant growth, oxidative stress parameters, and level of photosynthetic pigments in nine rice (Oryza sativa L.) genotypes collected from different locations in India, grown under 50 ^M and 100 ^M cadmium nitrate application. In all the rice genotypes, with an increase in Cd concentration in the growth medium, root and shoot growth as well as levels of Chl a, Chl b and carotenoids declined significantly compared to untreated seedlings. A significant elevation in the levels of H₂O₂ and lipid peroxidation was observed in the seedlings due to Cd treatment. The upland varieties of rice Sobhagi, Vandana and IDR-763 showed better growth performance, lesser H₂O₂ production and lesser oxidative damage due to Cd, compared to inland varieties. Results suggest that the rice cultivars Sobhagi, Vandana and IDR-763 appeared to be fairly tolerant to high Cd levels.