EFFECT OF ZINC ON CADMIUM TOXICITY IN WINTER WHEAT

Abstract

This nutrient solution experiment investigated the effects of zinc (Zn) and cadmium (Cd) on winter wheat growth and enzymatic activity. Twelve nutrient solution treatments were prepared of four zinc levels (0, 0.5, 5 and 50 mg L⁻¹) and three cadmium levels (0, 5 and 50 mg L⁻¹). Cadmium concentrations ≥5 mg L⁻¹ decreased plant growth, superoxide dismutase activity, and leaf and stem zinc concentrations, but increased plant cadmium concentrations, proline content, and peroxidase and catalase activities. Root activity and zinc concentration were highest in the 5 mg L⁻¹ treatment and lowest in the 50 mg L⁻¹ treatment. Zinc concentrations ≥5 mg L⁻¹ inhibited plant growth, but increased proline content and cadmium concentration in stems and leaves. Low levels of zinc (0.5 mg L⁻¹) increased cadmium-induced toxicity in wheat plants but high levels of zinc (50 mg L⁻¹) reduced. In conclusion, these results indicated that the addition of zinc alleviated cadmium toxicity if the zinc/cadmium ratio was >10/1. Additional study needs to be done to quantify zinc content before zinc is supplied to alleviate cadmium toxicity.

Keywords:

• zinc
• cadmium-induced toxicity
• growth inhibition
• oxidative stress
• winter wheat

ACKNOWLEDGMENTS

We thank the New-Century Excellent Talent Program of the Education Ministry of China (NCET-06-0866) and National Natural Sciences Foundation of China (40971179, 31071863) for their support of the study.