In lettuce from the sub-blocks with the nutrient medium containing 1.0 mg I dm−3, 0.5 mg Se + 1.0 mg I dm−3 and 1.5 mg Se + 1.0 mg I dm−3, foliar application of KIO3 and Na2SeO4+ KIO3decreased the level of Ca, Mg and Fe in roots, when compared to respective plants from the control sub-blocktion was statistically significant