The effects of Ethylene Diamine Tetraacetic Acid (EDTA) on uptake of zinc (Zn2+) and copper (Cu2+) by hydroponically grown mint leaf (Mentha piperita L.)

Abstract

This study was carried out to assess the effects of EDTA on zinc and copper uptake in the hydroponically grown mint leaf (Mentha piperita L) as well as their translocation factors in both chelated and unchelated treatments. In the present work, effects of EDTA on Zn²⁺ and Cu²⁺ uptake by mint leaf (Mentha piperita L.) seedlings replanted in hydroponic solutions in a greenhouse were investigated. Two months old seedlings, were exposed to various doses of Zn²⁺ and Cu²⁺ (0, 0.0025, 0.005, 0.0075, and 0.025 mg/L) and constant concentration of EDTA (0.0025M).  For unchelated treatments, the effects of increasing concentrations of Zn²⁺ and Cu²⁺ in the solution increases the uptake by the plants relative to control.  Zn²⁺ contents in the shoots showed more accumulation than in the roots (p<0.05) and also Cu²⁺ content in the shoots was higher than in roots. Hence, for the chelated treatments i.e. addition of 0.0025M EDTA to the solutions of Zn²⁺ and Cu²⁺ inhibits their uptake in both shoot and root of the plant at (0.0025, 0.005, 0.0075 mg/L) when compared to the unchelated treatment of same concentration. But at 0.025 mg/L, chelation does not have much effect on the Zn²⁺ and Cu²⁺ uptakes in both shoot and root of the plant (p>0.05) as the uptake in both chelated and unchelated treatments was almost constant. Hence, chelation inhibits translocation of Zn²⁺ and Cu²⁺ to the shoots of the plant at highest concentration of zinc and copper in the solution.

Keywords: Ethylene diamine tetraacetic acid, chelation, mint leaf, hydroponic, greenhouse.