BIOREMEDIATION OF HEAVY METAL STRESS BY RHIZOBIUM CHICKPEA SYMBIOSIS

Abstract

A pot experiment was conducted in Soil Bacterology Section, Ayub Agricultural Research Institute, Faisalabad, Pakistan to study the role of Rhizobium in heavy metal remediation in two consecutive years (2013-14 and 2014-15). Growth and yield of chickpea, under metal contaminated soil, was evaluated. At the time of pot filling copper was applied as CuSo4 .5H2 O @ 50, 100,150 and 200 mg kg-1 soil in all the treatment. In these treatments, chickpea seed was inoculated with peat based Rhizobium inoculums. Fertilizers @ 30-60 kg NP ha-1 were applied at sowing. The trial was laid out according to CRD having four repeats. The results revealed that post-harvest soil carried lower Cu contents compared to pre-sowing soil even without inoculation. However, Rhizobium inoculation decreased the Cu contents upto 73-98%. Significant increase in grain yield (16.8 g pot-1) was observed by Rhizobium inoculation at Cu concentration of 50 mg kg-1. The physical parameters of the plants like root/shoot length, biomass, dry weight, nodular mass and number of nodules plant-1 were also increased significantly at all Cu levels combined with Rhizobium inoculation. It is concluded that rhizobial inoculation exerted positive effect on growth of crop in metal infected soil.