INHIBITORY EFFECT OF CALCIUM ON CAESIUM ABSORPTION IN PLANT ROOTS.

Radiocaesium is released into the environment by accidents in nuclear facilities. One of the major issues related with this is the assessment and reduction of internal exposure of crops grown in contaminated soil. To solve this, we developed a method of inhibiting Cs absorption by plant roots. In the presence of potassium concentrations >100 μM, Cs absorption occurs mainly via voltage-insensitive cation channels (VICC). Since the transport activity of VICC was inhibited by calcium at millimolar concentrations, we hypothesised that Ca would effectively inhibit Cs absorption. We grew Arabidopsis and rice plants in the presence of Cs and Ca in the nanomolar and millimolar range and measured Cs concentrations in the plants using inductively coupled plasma mass spectrometry. The results showed that the Cs concentration in both plants decreased with increasing Ca concentration in the medium. This suggests that Ca has an inhibitory effect on Cs absorption.