Iodine biofortification of Eschscholzia californica Cham. and its effect on the mineral composition of plants

One of the greatest challenges facing global health policy is the burden of chronic non-communicable diseases caused by nutrient deficiencies. Plants' biofortification has been proposed as a method of introducing essential nutrients into the human diet. An increased level of one element can affect the content of others in the plant and, thus, the health-promoting properties of plant materials.

The study aimed to determine the effect of biofortification with mineral (KI) and organic forms of iodine: 5-iodosalicylic acid (5-ISA) and 3,5-diiodosalicylic acid (3,5-diISA) on the mineral composition of Eschscholzia californica plants grown in a hydroponic system. The following combinations were tested: (1) Control; (2) KI; (3) 5-ISA; (4) 3,5-diISA.

To determine the content of macro- and microelements (P, K, Ca, Mg, S, Al, Ba, B, Be, Bi, Co, Cr, Cu, Fe, Li, Mn, Mo, Na, Ni, Zn) using an ICP-OES spectrometer, plant samples were digested in HNO₃.

Control plants had the highest macronutrient accumulation. Particularly significant decreases were observed for K and Mg. The use of 5-ISA and 3,5-diISA resulted in a greater decrease in macronutrient content than KI, especially for P, K, and Mg. The concentrations of Be, Cr, and Fe did not differ significantly from those of the control group. The lowest concentrations of B, Ba, Li, Na, Al, Bi, Co, and Cu were observed after the use of mineral iodine. The content of most micronutrients was higher after the use of 5-ISA than after the use of 3,5-diISA. For Ni, all enrichment treatments increased the concentration of this element in the series 3,5-diISA > 5-ISA > KI, whereas KI and 5-ISA increased Zn concentration. The use of 5-ISA increased Al levels in the plant compared to the control group.