Phytoextraction is adsorbing the heavy metals using tolerant and accumulating plants, and then
transferring, storing at the overground parts. Studying the adsorption characterization of different plants
and screening high uptake plants is the key of this technology. According to the rules of U.S. department
of energy, the high uptake plants screened should have the following characterizations: 1) Have high
accumulating efficiency under the low contaminants concentration; 2) Accumulate high concentrations of
the contaminants; 3) Accumulate many different kinds of heavy metals; 4) Grow fast and with large
biomass; 5) Have pest and disease resistance ability [44].