137Cs Distribution in eleutherococcus sciadophylloides and the factor of high 137Cs concentration in the leaf after the fukushima daiichi nuclear power plant accident

Abstract

Eleutherococcus sciadophylloides is a popular edible wild plant among Japanese citizens, though its leaves are known to have relatively high 137Cs concentrations among the edible wild plants. Studies to investigate detailed 137Cs distributions of each tree part, such as leaves, stems, main roots and lateral roots, were scarce. In this study, we aim to investigate why the high 137Cs concentrations are in the leaves of E. sciadophylloides by measurements of proportions of 137 Cs content of each tree part and statistical analyses. Small sized samples of E. sciadophylloides were collected in spring and autumn in 2016 and 2017 in Fukushima Prefecture. The proportions of 137Cs content of each tree part were calculated by the 137Cs concentrations and the weights. Approximately 50％ of the total 137Cs content was located in the leaves in spring. The proportions of 137Cs content in the roots were relatively high compared with that in the stems in both seasons. The linear regression models indicated high positive correlations between the 137Cs concentrations in the lateral root and that in both inner bark of the stems and the main roots. It is suggested that 137Cs was translocated to the stems or the main roots through the inner bark. It is possible that the phenomenon which is the high 137 Cs concentrations in the leaves of E. sciadophylloides is caused by translocations related to seasons through the inner bark from the roots in addition to its features of shallow roots suggested by previous studies.