Specific arbuscular mycorrhizal fungal–plant interactions determine radionuclide and metal transfer into Plantago lanceolata

Abstract

Societal Impact Statement Industrial activity has left a legacy of pollution by radionuclides and heavy metals. The exposure of terrestrial environments to increased levels of ionising radiation and toxic elements is of concern, not only because of the immediate effects to biota but also because of the potential risk of mobilisation into higher levels of a food chain. Here, we present a study that extends our knowledge of how arbuscular mycorrhizal fungi contribute to the mobilisation of non‐essential elements in environments such as former mine sites, and provides a perspective that will be of interest for the management and remediation of such sites. Summary Accumulation and transfer of long‐lived radionuclides and toxic metals in terrestrial environments is of major concern because of potential mobilisation into food chains. In this study, we aimed to compare the role of four different arbuscular mycorrhizal fungal (AMF) cultures on the transfer of non‐essential elements into Plantago lanceolata from a naturally contaminated soil source. Soil from an abandoned uranium (238U) mine was collected as a natural source of 238U, thorium (232Th), arsenic (As) and lead (Pb). P. lanceolata was inoculated with four AMF cultures (Rhizophagus irregularis DAOM181602, Acaulospora longula BEG8, Scutellospora calospora BEG245 and Funneliformis mosseae BEG12) to compare the uptake and transfer from root to shoot. Inductively coupled plasma (ICP) mass spectroscopy and ICP‐absorption emission spectroscopy analyses provided quantification of total elemental concentrations in soil and plant tissues. Two of the AMF cultures, A. longula and F. mosseae, had contrasting roles in toxic element partitioning in plant tissue of P. lanceolata. F. mosseae increased the accumulation of 238U, 232Th, Pb, As and Cu in shoots whereas A. longula induced increased partitioning of 232Th, Ca, Fe and Zn in roots. The inoculation treatments and the differential accumulation of these elements had no significant effect on plant biomass. The use of different AMF cultures in enhancing phytoremediation of contaminated environments requires a wider understanding of the contribution of different AMF cultures to non‐essential element acquisition as well as to plant nutrition.

Keywords

• arbuscular mycorrhizal fungi
• arsenic
• lead
• Plantago lanceolata
• radionuclides
• thorium