Distribution pattern of rare earth elements in fern: implication for intake of fresh silicate particles by plants.

All the lanthanide elements (REE) in fern (Matteuccia) and in soil were determined with inductively coupled plasma mass spectrometer (ICP-MS) in order to discuss REE behavior in fern. The fern sample was divided into three parts: root, stem, and leaf; the soil of the same site was also sampled and the soil sample was divided into two parts: HCl and HNO3 soluble part (soil[HCl]) and HF soluble part (soil[HF]). REE in each part was determined by ICP-MS after solvent extraction separation. The overall variation of the REE pattern of the root does not resemble that of the whole soil, but that of the HF soluble part. A tetrad effect variation (W-type) was found in the REE patterns of root, stem and leaf; more conspicuous tetrad effect variation was observed in HREE region than in LREE region, and was so in stem and leaf than in root. Negative anomalies of Ce were observed in the REE patterns of root, stem and leaf, with bigger anomalies in stem and leaf than in root. The results of this study suggest that REE in fern has come from silicates of soil and has once been in dissolved state.