Hyperaccumulation capacity and resistance physiology of <italic>Microsorum pteropus</italic>, an aquatic fern to cadmium

Abstract

Hyperaccumulators play very important role in phytoremediation of environment polluted by exceed heavy metals, since they could hyperaccumulate heavy metals in their tissues and tolerant high concentrations of heavy metals. The present study reported an aquatic fern— Microsorum pteropus , which might has the potential to be a hyperaccumulator for cadmium (Cd) in water environment. We set two group exposure experiments with different Cd concentrations, low dose groups (0, 0.1, 1, 5, 10, 20 mg/L) and high dose groups (0, 20, 40, 60, 80, 100 mg/L). After seven days Cd-exposure, we found that the order of Cd accumulation concentrations in the tissues was adventitious root>leaf>petiole>rhizome, and that the bioconcentration factors (BCF) could reach as high as 920.21 in adventitious root under 0.1 mg/L Cd-exposure. The remove efficiency of the plant to Cd varied from 39.12% to 53.99% in different Cd-exposure concentrations after seven days culture. At 60 mg/L Cd exposure level, the Cd accumulation concentrations in the adventitious root and leaf tissues were (3738.39±348.03), (10652.53±2477.74) mg/kg, respectively. Meanwhile, chlorophyll concentrations, malondialdehyde (MDA) concentrations, peroxidase (POD) activity, superoxide dismutase (SOD) activity and chlorophyll fluorescence parameters showed no significant change between Cd treatments and the control. These results mean that Microsorum pteropus have significant hyperaccumulation capacity and remarkable resistance to Cd, which might suggest that this aquatic fern could service as a hyperaccumulator for the phytoremediation of Cd-polluted water environment.