Relationship between Zn and Cd in soil and plant

Abstract

The relationship between Zn and Cd uptake by plants is somewhat controversial according to the lack of information about this subject. The objective of this study was to increase our scientific understanding of soil about plant factors controlling Zn and Cd bioavailability and uptake. This experiment was carried out in the winter season of 2019. It aimed to solve the mystery of the Zn and Cd relationship in soil and plant uptake. Five plant species were under observation (carrot – Daucus carota, radish – Raphanus sativus, wheat – Triticum aestivum L., lettuce – Lactuca sativa and bean – Vicia faba). Plants were planted in plastic pots containing 2 kg sandy loam soil with duplicate and exposure to six Zn:Cd ratios (1:0.5, 1:1, 2:1, 3:1, 4:1 and 5:1) with increasing elements molar ratio of Zn to Cd in soil. After 45 days, plants were harvested. Zn and Cd were determined in roots and shoots. Results showed, that at low molar ratios of Zn:Cd in soil, the relationship between these metals in soil is almost synergistic and both elements are accumulated easily in plant tissues, but at high molar ratios, the relationship between these metals is almost antagonistic where Cd be more competitive to Zn uptake by plants. It was concluded that the 2:1 Zn:Cd ratio in the soil is the border between synergistic and antagonistic relationships.