Effects of silicon on the growth, nutrient uptake and cadmium accumulation of tomato seedlings

Tomato plant (Solanum lycopersium Mill.) is among the highly cultivated vegetable crops worldwide. With the increase in cadmium (Cd)-polluted area, the risk of tomato safe production has increased. Therefore,ahydroponic experiment was conducted to study the effects of silicon (Si) on the growth, nutrient uptake and Cd accumulation of tomato seedlings. Tomato seedlings were grown in Yamazaki's nutrient solutionwith fourdifferent Cd levels (0.5, 1, 2 and 3 mg/L) along with four Si treatment levels (0, 1, 2 and 3 mmol/L). The results showed that the addition of Si improved the growth and activities of antioxidant enzymes (SOD and CAT) as well as the nutrient uptake (Ca, Mg, Fe, Mn and Zn) of tomato seedlings under different Cd exposure levels compared to Cd treatment alone. The addition of Si decreased the Cd content in the roots and shoots of tomato seedlings, and the Cd content in the roots and shoots was lowest when the Si concentration was 3 mmol/L. In conclusion, the negative effect of Cd on the growth of tomato seedlings was alleviated by Si-induced increases in biomass, activities of antioxidant enzymes and nutrient uptake and inhibition of Cd uptake.