Abstract
To clarify the mechanism of Cd accumulation of Athyrium yokoscense (Ay), which is a metal hyper-tolerator/accumulator fern in Japan, the Cd distribution was compared to some plants. Here, we report a result from the ICP-AES analysis of Ay and Tobacco (Nt) plantlets cultured in two different basal medium, 1/4MS and 0.5 mM CaCl2, both of which containing 0.1 μM of Cd for 24 hours. The entire Cd accumulation (ECA) of 1/4MS-grown Ay was greater than that of Ca-grown Ay. Although about 90 % of the accumulation was in roots in 1/4MS-grown Ay, a decrease in ECA with a stable transport of Cd from roots to shoots induced a significant decrease in the relative distribution ratio (RDR) of roots in Ca-grown Ay. On the other hand, ECA of 1/4MS-grown Nt was similar to that of Ca-grown Nt. However, the large parts of Cd was accumulated in shoots, resulting the large RDR, in 1/4MS-grown Nt, while both the absolute accumulation and the RDR in shoots decreased in Ca-grown Nt. In relation to these results, the accumulation of the other elements also indicated a typical changes. Results suggest a difference of mechanism related to the Cd absorption in Ay and Nt.
