Europium(III) as luminescence probe for radionuclide interactions with plant cells

Abstract
The understanding of the interaction of radionuclides (RNs) with plant cells serves as basis to explore their transfer in the environment and their uptake into the food chain. Europium(III) is used as an analog for the hazardous actinides Am(III) and Cm(III). Our study describes the interaction of Eu(III) with tobacco (Nicotiana tabacum) BY-2 cells on the cellular and molecular level. Cellular level experiments included the determination of the cell viability, the cell growth, and the homeostasis of macro- and microelements in the presence of Eu(III) as well as its bioassociation by the plant cells. Whereas molecular level investigations are focused on the Eu(III) speciation in media and cells applying different complementary luminescence spectroscopic techniques (UV-excitation and direct excitation). Different Eu(III) species could be distinguished in the media after separating the cells and on the BY-2 cells. The characteristic sum spectrum of the cell-bound Eu(III) depicts a very strong intensity of the hypersensitive 5D0  7F2 transition. The cellular and molecular level investigations with BY-2 cells will be compared with results obtained with Daucus carota [1] and Brassica napus cells [2]. The spectroscopic results indicated differences in the Eu(III) speciation on BY-2 cells on one side compared with D. carota and B. napus cells on the other side.

References
[1] J. Jessat; et al. A comprehensive study on the interaction of Eu(III) and U(VI) with plant cells (Daucus carota) in suspension. J. Hazard. Mater. 439; 2023; 129520.
[2] J. Jessat; et al. Bioassociation of U(VI) and Eu(III) by plant (Brassica napus) suspension cell cultures – A spectroscopic investigation. Environ. Sci. Technol. 55; 2021; 6718 – 6728.