Iodine biofortification of cabbage plants cultivating in hydroponic system

Iodine is an essential trace element in the human diet being involved in the synthesis of thyroid hormones. Iodine deficiency affects ca. 2.2 billion people worldwide, therefore it is an important challenge to find a plant-based source of iodine, which would provide the recommended dietary allowance. In this work iodine biofortification of cabbage was studied cultivating plants in hydroponic system containing iodine in concentration of 0.01-1.0 mg/L as potassium iodide or potassium iodate. During the experiment plant physiological properties, biomass production, concentration changes of iodine- as well selected essential elements were investigated. In addition, chemical form of the accumulated iodine in root samples was also determined. Results showed that iodine addition had no effect on the photosynthetic efficiency and chlorophyll content. Biomass production was stimulated by the iodide treatment in all dosages, while applying iodate this phenomenon was observed only in low concentrations, above 0.5 mg /L the yield was reduced. Increasing iodine concentrations in the nutrient solutions resulted in higher iodine content in all plant parts, the presence of iodide caused 2-7 times higher accumulation compared with the iodate treatment and it was established that in cabbage roots reductive reactions are dominant, iodate was converted to iodide.