Phytoremediation Potentials and Effects of Lead on Growth of Pteris vittata L. and Pityrogramma calomelanos L. (Pteridaceae: Fern)

Phytoremediation, tolerance and bio-accumulation potentials of lead in the roots and shoots of Pteris vittata and Pityrogramma calomelanos were investigated to ascertain the effects of lead on thee species’ growth and development. Within the experiment, 5 kg of air dried and sieved soil was put inside six plastic pots labelled CT, A, B, C, D and E, each with different concentrations (0, 200, 400, 600, 800 and 1,000 ppm) of lead (II) trioxonitrate (v) salt. The shoots and roots of the plants were air dried, grounded and analysed for lead quantities using x-ray fluorescence before and after the treatments. One-month old healthy fernlets of each species were transplanted into each of the pots, in six replicates. Growth parameters such as leaflet area, number of leaflets and frond height were recorded weekly, for 12 weeks. Quantitative data were analysed for significant difference using analysis of variance for each of the plant species and means were evaluated with Duncan's multiple range test for frond height, leaflet number, leaflet area, roots and shoots biomass. Negative effects (decrease) on the growth parameters were observed in both species. Pteris vittata accumulated more lead in all the treatments, in both shoots and roots, compared with Pityrogramma calomelanos. The highest bio-accumulation factor in Pteris vittata shoot was 2.944 and 0.635 in Pityrogramma calomelanos.Transfer factor of Pteris vittata was 1.742, while for Pityrogramma calomelanos was 0.859 in all the treatments. It could be concluded that Pteris vittata is a better bio-accumulator, tolerated more lead and therefore could be used in remediating lead-contaminated soils, better than Pityrogramma calomelanos