LAUSR

This study aimed to evaluate the effect of rice plant root activity on the chemical form of stable iodine (I) in a cultivated soil solution. Concentrations of I-, IO3- and organic-I were analyzed 4 days after exposure I- or IO3- solutions to each of the cultivated soil surface. When exposed to I-, its concentration in the cultivated soil was approximately the same as that in the non-planted soil. When the rhizosphere was exposed to IO3-, the I- concentration in the soil increased under cultivation conditions. IO3- remained undetected in the soil solution. The organic-I concentration in the cultivated soil solution was higher than that in the non-cultivated soil. Concentrations of organic-I increased under IO3- addition compared to I- addition. A weak positive correlation was observed between the TTC-reducing activity of plant roots, and the total and organic-I concentrations in the soil solution. It was suggested that the amount of organic I formed from IO3- was determined by the reducing activity of the roots.