Effect of cadmium toxicity on micronutrient concentration, uptake and partitioning in seven rice cultivars

Abstract

Heavy metal uptake, translocation and partitioning differ greatly among plant cultivars and plant parts. A pot experiment was conducted to determine the effect of cadmium (Cd) levels (0, 45 and 90 mg kg⁻¹ soil) on dry matter yield, and concentration, uptake and translocation of Cd, Fe, Zn, Mn and Cu in seven rice cultivars. Application of 45 mg Cd kg⁻¹ soil decreased root and shoot dry weight. On average, shoot and root Cd concentrations and uptake increased in all cultivars, but micronutrients uptake decreased following the application of 45 mg Cd kg⁻¹. No significant differences were observed between 45 and 90 mg kg⁻¹ Cd levels. On average, Cd treatments resulted in a decrease in Zn, Fe and Mn concentrations in shoots and Zn, Cu and Mn concentrations in roots. Differences were observed in Cd and micronutrient concentrations and uptake among rice cultivars. Translocation factor, defined as the shoot/root concentration ratio indicated that Cu and Fe contents in roots were higher than in shoots. The Mn concentration was much higher in shoots. Zinc concentrations were almost similar in the two organs of rice at 0 and 45 mg Cd kg⁻¹. A higher Cd level, however, led to a decrease in the Zn concentration in shoots.

Keywords:

• cadmium toxicity
• micronutrients uptake and translocation
• rice growth

Acknowledgement

The authors thank the Department of Soil Science, Shiraz University, Iran for providing facilities to undertake this study.