PHYTOEXTRACTION POTENTIAL OF LEAD BY THREE PLANT SPECIES (TARAXACUM OFFICINALE, ARABIDOPSIS THALIANA, AND HELIANTHUS ANNUUS) WITH AN ECOLOGICALLY FRIENDLY ORGANIC AMENDMENT

Abstract

This work aimed to examine the ability for phytoaccumulation of Pb in roots and shoots parts of three plant species Taraxacum officinale (TO), Arabidopsis thaliana (AT), and Helianthus annuus (HA) grown in pots containing agricultural soil (AS) contaminated with lead and a combination of AS + organic amendment (kitchen compost). In addition, the bioaccumulation and translocation factors were also evaluated. The high contamination with heavy metals in the soils of the Mantaro Valley, Peru, and the few reported studies using organic amendments with three species led to evaluating the ability of three plant species: Taraxacum officinale (TO – the dandelion), Arabidopsis thaliana (AT – the thale cress), and Helianthus annuus (HA – the sunflower) for phytoaccumulation of Pb in their roots and shoots. Plants seeds were grown in pots containing agricultural soil (substrate A) with lead (764 mg kg-1) and agricultural soil + organic amendment (substrate B – 681 mg kg-1). The treatments were arranged in a randomized design 3 x 2 factorial, with three replicates. Pb contents in plants were increased after Pb exposure. TO (69.28 ± 2.58 mg kg-1; 59.21 ± 1.23 mg kg-1) and AT (47.81 ± 2.18 mg kg-1; 17.29 ± 0.84 mg kg-1) were the species with the highest Pb content in the roots, and HA (53.17 ± 1.15 mg kg-1; 37.72 ± 2.76 mg kg-1) in the shoots for both substrates (A; B). The highest bioaccumulation factor (BF) was registered rather in root than shoot, with values smaller than one for both substrates. The AT species obtained a higher translocation factor (TF) of 2.91, followed by TO (1.65) for substrate A. For substrate B, TO showed a value of 1.57, followed by AT (0.76). The three species showed their ability for remediation of Pb from contaminated soils.