The effects of cadmium and zinc interactions on the concentration of cadmium and zinc in pot marigold (Calendula officinalis L.)

摘要

Experiments were conducted on pot marigold (Calendula officinalis L.) plants grown under glasshouse conditions to study interactions between Cd and Zn and the effects of these on the respective concentrations of these metals in plant tissues (leaves and petals). A factorial experiment with two factors (Cd and Zn) at five concentrations (0, 1, 5, 10, 15 mg kg-1) was carried out. Cadmium was applied as CdSO4·8/3H2O and Zn as ZnSO4·7H2O. Increasing Cd and Zn additions to the soil resulted in an increase in the concentration of Cd and Zn in plant tissues, as well as in the amounts of Cd and Zn extracted by diethylene triamine penta-acetic acid–triethanol amine (DTPA–TEA). Significant inhibitory effects of Zn on Cd concentration in the leaves occurred at levels above 5 mg Zn kg-1 soil. Zinc concentrations in the leaves decreased, while those in the petals increased with increasing rates of applied Cd. Cd application increased the Cd/Zn ratio and Zn application reduced the Cd/Zn ratio of plant tissue. DTPA–TEA-extractable Cd and Zn significantly correlated with the Cd and Zn concentrations within the leaves and petals, indicating that such determinations could be used to predict Cd and Zn concentrations in the plant tissues of pot marigold.