Boron application mitigates Cd toxicity in leaves of rice by subcellular distribution, cell wall adsorption and...

Cadmium (Cd) is a hazardous heavy metal and some of its negative effects include inhibition of rice growth, while also accumulates in the rice grains. Boron (B) has been implicated in mitigating Cd toxicity. Nevertheless, a few studies have been performed up to now to evaluate whether B could encourage Cd tolerance in rice by regulating Cd adsorption on cell walls (CW) in leaves of rice. The current experiment used different concentrations of B (0, 20, and 30 µM) along with 50 µM Cd to rice seedlings. The results indicate that single treatment of Cd significantly inhibited root and shoot growth and caused leaf chlorosis. However, B application at 20, and 30 µM reduced Cd concentrations in the roots by 66% and 77%, and in shoots by 72% and 83%, respectively, and increased plant development. Boron supply at 30 µM increased Cd in leaf CW fraction by 79% and decreased Cd by 64% in the organelle fraction. Moreover, B addition regulated the antioxidant system and decreased malonaldehyde contents (45%) in rice leaves. The present study demonstrates that B reduces Cd translocation and facilitates Cd adsorption on CW and regulates an efficient antioxidant system in rice leaves.