Due to mining processes, the soil of our study site at A mine contained high
concentrations of heavy-metals, which would be detrimental to plants. However, Miscanthus sinensis was found as dominant species there and known to be growing at many old mine sites in Japan. The purpose of our research is to elucidate the heavy-metal tolerance mechanism of M. sinensis in A mine, considering the effects of root endophytic fungi.
The metals concentrations in each plant tissue were measured by ICP-OES and it suggested that M. sinensis accumulated zinc (Zn) and lead (Pb) in the underground part and dead parts (root barks and dead leaves). Organic and phenolic acids extracted from adventitious roots were analyzed by GC/MS and HPLC-DAD, respectively, and succinic and chlorogenic acids were detected as mainly detoxifying compounds in adventitious roots.
Root endophytic fungi, dark-septate endophytes (DSE), which are known to enhance heavy-metal tolerance in plants, showed highest appearance rate (72%). Talaromyces sp. showed low appearance rate (22%), but this fungus showed high production of Zn-chelating compounds, which might detoxify Zn accumulated in adventitious roots. It is necessary to clarify whether or not DSE and Talaromyces sp. could enhance heavy-metal tolerance in M. sinensis, via inoculation test.