Teucrium as a Novel Discovered Hyperaccumulator for the Phytoextraction of Ni-contaminated Soils

Abstract

The success of phytoextraction, a promising new method that uses green plants to detoxify metals, depends upon the identification of suitable plant species that hyperaccumulate heavy metals in their above ground parts. In this study, the roots and above ground parts of the Teucrium polium plants grown in serpentine and non-serpentine soils as well as soil samples were analyzed for their Ni and Co concentrations. The Ni concentrations between 9,678 and 14,110 mg kg(-1) in above ground parts of Teucrium polium plants grown in serpentine soils were found together with the translocation factors between 2.23 and 3.23, and enrichment coefficients between 5.9 and 9.2. The cobalt concentrations in the same samples were found to be in the ranges of 3.1 and 6.4 mg kg(-1) together with the translocation factors 2.8 and 15, and with enrichment coefficients of 0.01 and 0.03. The Ni/Co-ratios in the ammonium chloride and ammonium acetate extracts of the soils were found to be higher than 4 and 10 fold for the serpentine soils, respectively, while the values were below or about 1-fold for both the extracts of the non-serpentine soils. The ratios of Ni/Co concentrations in the roots and aboveground parts of Teucrium polium grown in the serpentine soil were significantly higher (up to 12,857-times) than the ratios for Teucrium polium grown in the non-serpentine soils (up to 8.1-times). These values are highly important and the original results. Consequently, Teucrium polium, a new hyperaccumulator plant for nickel, has been discovered and suggested for phytoextraction of Ni in contaminated soils.