Translocation and some forms of germanium in rice plants

Germanium(Ge) exhibited a strong inhibition on the growth of rice plants and necrotic spots appeared on leaf bladea which had absorbed 5 ppm Ge via their roots for 4 days. The translocating form of Ge in the exudate was found to be 68GeO2 which was the form given to the roots. Nearly equal radioactivities of the 68Ge in the shoots were extracted from the water-extractable, 0.25 N HCl-extractable and residual fractions. The radioactivities in the water extractable fraction were fractionated into 2 peaks by a molecular sieving effect using a Sephadex G-25 column. Some of the 68Ge in the higher molecular fraction was found to be associated with proteins. On the other hand, the 68Ge in the smaller molecular fraction was proved to be an unchanged form of the 68GeO2 which had been given to the roots.