Comparison of Lead Tolerance and Accumulation Characteristics of Fourteen Herbaceous Plants

Abstract

To compare lead (Pb) tolerance and accumulation characteristics, 14 herbaceous plants were treated with different concentrations of lead (0 mg?kg-1, 500 mg?kg-1, 1000 mg?kg-1, 1500 mg?kg-1, 2000 mg?kg-1) through an indoor pot experiment. Results indicated that the shoot dry weights (DWs), tolerance index (TI) and root tolerance index (RTI) of 14 herbaceous plants decreased with the increase of lead concentration. After comprehensive evaluation, Campsis grandiflora, Polygonum lapathifolium, Lolium perenne, and Poa annua were confirmed as tolerant plants to be cultivated in lead-zinc mining area. Moreover, shoots of the Rudbeckia hirta could effectively absorb the lead (I I) with the bioconcentration factor (BCF) of 2.29. The translocation factor (TF) of 6 herbaceous plants were larger than 1.0. They are: Polygonum lapathifolium (3.04) > Medicago sativa (2.49) > Rudbeckia hirta (1.72) > Talinum paniculatum (1.44) > Capsicum annuum cv. 276 (1.36) > Trifolium repens (1.21. Finally, after integration the BCF, TF and repair potential indices, we found that Rudbeckia hirta had a good restoration potential and its lead cumulation in the shoot was the highest (2.576 mg per plant) when the concentration was up to 1000 mg?kg-1. Therefore, Rudbeckia hirta could be identified as a pioneer species of Pbhyperaccumulator.

Keywords

• environment