Phytoremedial Potential of Tagetes Erecta Under Mycorrhizal Inoculation in Heavy Metal Polluted Soil

Abstract

Investigation of the growth of Tagetes erecta under different levels of contamination of Copper (Cu) and Lead (Pb) in the soil and effects of mycorrhizal species (Glomus mosseae) on Cu and Pb to identify hyperaccumulator plants in tropical environment that could be used in remediation of heavy metal from contaminated soils. It was a greenhouse experiment consisted of factorial combination of two heavy metal (Cu and Pb) treatments which were replicated three times in Complete Ramdomized Design (CRD) with two mycorrhizal (Glomus mosseae and non-mycorrhizal) treatments. Metal solutions of Cu and Pb at the concentrations of Cu are 0, 125, 250, 500, 1000 mg kg^-1 and concentrations of Pb are 0, 25, 50, 75, 100 mg kg^-1 were prepared using CuCl₂ and PbCl₂ soluble compounds respectively. Soil mycorrhizal inocula of Glomus mosseae was applied at the rate of 20 g per pot. Five seeds of Tagetes erecta were planted per pot and were thinned to two stands per pot at two weeks after planting. Pre- and post- soil tests were carried out to determine soil physical and chemical properties, using standard methods. At 12 Weeks After Planting (WAP), Tagetes erecta was harvested and analyzed for Copper and Lead uptake using Atomic Absorption Spectrophotometer. The data collected were analyzed using descriptive and inferential statistics. The results showed that Arbuscular Mycorrhizal Fungi enhanced the number of leaves, height and stem girth of Tagetes erecta in high concentration (1000 mg kg^-1) of Cu contaminated soil. Glomus mosseae inoculation did not enhance the growth parameters of Tagetes erecta irrespective of the levels of Pb contamination Glomus mosseae inoculation significantly (p≤0.05) increased Cu uptake of Tagetes erecta at 500 mg kg^-1 of Cu concentration of a polluted soil. In contaminated soil, containing 50 mg kg^-1 Pb Glomus mosseae significantly (p≤0.05) increased Pb uptake in Tagetes erecta.