EFFECT OF MYCORRHIZAL INOCULATION ON THE GROWTH AND PHYTOEXTRACTION OF HEAVY METALS BY MAIZE GROWN IN OIL CONTAMINATED SOIL

Abstract

Pot experiments were conducted to investigate the effect of AM (Glomus mosseae) fungi inoculation (M) on the growth of maize and phytoextraction of selected heavy metals from a soil contaminated with crude oil (C). Four soil treatments, each with three replicates i.e., C+ M+ , M+ , C+ and control (without oil and inoculum) were conducted. Half of the pots with the soil treatments were planted with singly sown (SS) and the other half with densely sown i.e., four maize seedlings (DS). Various plant growth attributes were measured at weekly intervals Cu2+, Ni2+, Pb2+ and Cd2+ in the soil, root and shoot of maize plants were determined separately. Inoculation by AM promoted the vegetative growth attributes in both treatments viz., C+ M+ and M+ . AM inoculation also promoted the hyperextraction of heavy metals from C+ M+ soils, but inhibited by soils treated with M+ . High planting density i.e., DS also promoted phytoextraction of heavy metals from uncontaminated (M+ ) soils, but had minimal effect on phytoextraction from oil contaminated soils (C+ ). Planting density complemented the promotive effect of AM inoculation on phytoextraction of heavy metals from C+ soils. The hyperextraction of selected metals from soil is more favored by planting density in C+ soils, whereas AM inoculation tends to exclude heavy metals from potted plants. However, in case of C+ M+ soils, AM inoculation promotes the hyperextraction of metals more than planting density. While the combination of the two phenomena act synergistically to promote metal hyperextraction from C+ M+ as well as M+ soils.