Abstract
Water-cultured rice plants were exposed to 89Sr or 137Cs through roots for five days at their various growth stages and continued to grow until harvest. The harvested grains were radiochemically analysed and the concentration factors were calculated.
The maximum uptake of 137Cs in the grains was found at the booting stage, while that of 89Sr was at the flowering stage. The Cs uptake was 400 times higher at the booting stage, and 30 times higher at the flowering stage than those with Sr.
The growth stage dependency of the uptake of Sr and Cs was the most important factor for a selective enrichment of Cs in rice grains.
The specific affinity of Cs to cell sap and that of Sr for membrane substances of rice grains probably caused a selective redistribution inside the plant body.
