Effect of aminopolycarboxylic acids on germination and phytoremediation capacity of Echinochloa crus galii (L.) Beave in lead contaminated soil

Pot experiment was carried out to investigate the effects of two aminopolycarboxylic acids: EDTA and DTPA on morphological characters of Echinochloa crus galii (L.) Beave (germination, biomass, root and shoot lengths). The bioconcentration factor (BCF), چ translocation factor (TF) and tolerance index (TI) were also calculated to determine the Lead phytoextraction efficiency. The soil samples spiked with 0. 71 gli-1 Pb (PbNO3) and seeds of the plant were buried evenly throughout the pots. Aminopolycarboxylic acids were added to the soil after sowing. The treatments comprised the following dosages EDTA (1. 5, 5, 10 mmolkg-1) and DTPA (1. 5, 5, 10 mmolkg-1) and control pots (C: uncontaminated soil) were not treated with EDTA and DTPA. After two weeks, germination rate and percentage, biomass, root and shoot lengths of the plants were measured from the soil surface to the terminal bud after 60 days. Plants species were harvested and preliminarily dissected in root and shoot to recognize the concentration of Pb in plant tissues. According to the results, EDTA and DTPA application had significant (p <0. 05) effects on morphological characters and accumulation of Pb in the plant. Data showed that maximum germination, root and shoot length and biomass was achieved by control treatment, but the maximum bioconcentration factors (BCF) and translocation factor (TF) were observed for 5EDTA and 10DTPA treatments respectively. The effects of EDTA and DTPA on TI (Tolerance Index) showed that the index decreased with increasing doses of both aminopolycarboxylic acids. The results indicated that E. crus galii can tolerate Pb concentration, and EDTA and DTPA had potential to promote the uptake of Pb for the species, but with respect to inhibitory effects of EDTA and DTPA on plant growth and their environmental leaching risks to the ground waters, low dose should be used.