It is based on the observation of increased content of iodine and selenium in roots of plants treated foliarly with:
Na2SeO4and Na2SeO4+ KIO3(for selenium content in roots) or KIO3 and Na2SeO4+ KIO3(for iodine content in roots) in relation to other combinations with foliar application in the control sub-block. The causes as well as mechanisms underlying this effect are still unclear and require further studies