EFFECT OF RICE PLANT ROOT TTC-REDUCING ACTIVITY ON THE CHEMICAL FORM OF IODINE IN CULTIVATED SOIL SOLUTIONS

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.