Phytostabilization of cadmium contaminated soils by Lupinus uncinatus Schldl.

Abstract

Phytoremediation offers the benefits of being in situ, low cost and environmentally sustainable. Lupinus species is starting to generate interest for phytoremediation of soils showing intermediate metal pollution. The aim of this study was to explore the accumulating behavior and tolerance of Lupinus uncinatus Schldl. towards increasing Cd concentrations in soil. For this purpose the effects of different Cd treatments on plant growth, survival, metal tolerance, Cd accumulation and distribution in various plant organs were investigated. An 18 week pot trial was performed under greenhouse conditions. Cd was added as CdCl2.2.1/2H2O at the rate of 0, 3, 6 and 9 mg Cd/kg soil at three different occasions (after 4th, 12th and 15th week of plant growth) with four replicates. The Cd treatments applied, thus, were 9, 18 and 27 mg/kg. Cd inhibited plant height and number of leaves and induced a significant change in dry matter yield of roots, stems and leaves. Metal tolerance indices of 88, 82 and 49% were obtained for 9, 18 and 27 mg Cd/kg treatments. The maximal shoot Cd concentration (stem+leaves) of 540 mg Cd/kg dry matter was found at 27 mg Cd/kg treatment. The poor translocation of Cd from roots to shoot was evident from shoot:root ratios <1. The present work is the first report about the growth performance of L. uncinatus under Cd stress, its degree of tolerance and pattern of Cd accumulation in response to varying Cd treatments in soil suggesting the use of L. uncinatus for phytostabilization and revegetation of Cd polluted soils.