Effect of Cadmium on Uptake and Translocation of Three Microelements in Cotton

Abstract

A hydroponic experiment was conducted in a greenhouse to study the effect of cadmium (Cd) on uptake, accumulation, and distribution of three microelements [zinc (Zn), copper (Cu), and iron (Fe)] in cotton during ontogenesis and their difference among genotypes, using 3 genotypes with different Cd tolerances: Zhongmian 16, Zhongmian 16-2 (relatively tolerant-genotypes); and Simian 3 (relatively sensitive-genotype) and treated with 4 Cd concentrations (0, 0.1, 1, and 10 µM). Cadmium concentration in various organs was in the order: root > petiole > xylem > fruiting branch, leaf > phloem in vegetative organs; and in the order: seed coat, seed nut > boll shell > fiber in reproductive organs, respectively. There were no significant differences in Zn, Cu, and Fe concentrations of functional leaves and petioles between 0, 0.1, and 1 µM Cd treatments, while a significant increase with highly significant genotypic difference was observed in 10 µM Cd treatment, when compared with the control. A significant reduction in aboveground vegetative organs and increase in roots were observed for Zn concentration of cotton plants exposed to 1 or 10 µM Cd. The reduction or increase in Zn concentration by Cd differs significantly among the 3 genotypes. One and 10 µM Cd lowered Zn, Cu, and Fe concentrations in aboveground vegetative organs, while increasing concentrations in root, implying that the translocation of these elements from roots to shoots was prevented by Cd treatments. Cadmium treatment did not affect Zn, Cu, and Fe concentration in seed coat, seed, and fiber, while it decreased concentrations in boll shell for all genotypes.

Keywords:

• Cadmium (Cd)
• Cotton (Gossypium hirsutum L.)
• Interaction
• Microelement
• Translocation
• Uptake

Acknowledgments

We are deeply indebted to The British Council for its support to this project (SHA/992/310).