Clethra barbinervis, a deciduous broad-leaved tree in Japan, has been well known as a specific species which accumulates Cd, Co, Ni and Zn in its leaves. However, a few studies on metal accumulation in the other organs than leaves have been reported. In this study, we investigated the element concentrations in various organs and the characteristics of metal uptake and accumulation of this trees taken from different geological environments.

The samples of the plants were collected from two sites with different bedrocks (Takenowa: serpentine, Kamiyoshida: crystalline schist) in Aichi prefecture. Five mature trees were selected, and various organs were collected from each tree. Three soil samples were collected from surface horizon in both sites. The element concentrations were determined using ICP-AES after wet digestion with HNO₃ for plant samples and extraction with 0.1 M HCl for soil samples.

The results showed that Ni concentrations in all organs were higher in Takenowa than Kamiyoshida. This trend reflects the Ni concentrations of soils. Conversely, Co concentrations in leaves, flower bud, berry, bark, xylem were higher in Kamiyoshida than Takenowa nevertheless the concentration in soils was higher in Takenowa. This means that the uptake mechanisms might be different between Ni and Co in C. barbinervis.