Abstract
The fern gametophytes are free-living unlike those of a seed plant, meaning that the gametophytes have to adapt to the external environment. In this work, we characterized the heavy metal tolerance and accumulation in the gametophytes of Athyrium yokoscense, because the sporophyte is known as a metal hyperaccumulator.
First, we examined the effects of Pb2+, Cd2+, Cu2+, Zn2+ and H2AsO4- on fern spore germination. The germination of Athyrium spores was highly tolerant to these metals among several fern species, although Pteris vittata spores showed intensive tolerance to H2AsO4-. Athyrium gametophytes were also found to accumulate lead up to 23,337 mg/kg dw when the gametophytes were cultured in the presence of 10 μM Pb2+ Furthermore, it was shown that the lead was accumulated in the rhizoid, as determined by histologic staining method with rhodizonate. At present, we are further analyzing the localization of lead using TEM.
