Eschscholzia californica Cham. (California poppy, Papaveraceae) is a plant native to North America. Although it is primarily an ornamental plant, it also has potential applications in herbal medicine. Extracts of E. californica are used for its sedative and sleep-inducing properties. One way to increase the pro-health and nutritional value of plants, as well as accelerating their growth, is enriched fertilization. This practice is known as biofortification. Of particular interest is the iodine enrichment of crops, which serves to introduce this element into the human diet. It is an alternative to the iodisation of table salt, the excessive use of which poses risks to human health. E. californica plants were grown hydroponically in a greenhouse. The plants were watered with a standard nutrient solution enriched with the following: 1) potassium iodide (KI), 2) 5-iodosalicylic acid (5I-SA), and 3) 3,5-diiodosalicylic acid (3,5-diISA). The control group was watered with a nutrient solution that did not contain iodine compounds. The concentrations of vitamins and sugars in plants from the experimental groups were compared to those in the control one. Cultivation with KI and 5I-SA resulted in higher mean fresh shoot weights. Plants fertilized with KI and 3,5-diISA showed an increase in the mean total sugar concentration. Importantly, increases in the mean concentrations of vitamins B2 and B7 were noted in the KI group, whereas an increase in vitamin B1 was observed in the 5I-SA and 3,5-diISA combinations. These results demonstrate that iodine compounds can have a beneficial effect on nutritional and health-promoting properties of E. californica plants as well as on accelerating its growth.

„This research was funded in whole by the National Science Centre, Poland (grant no. UMO-2024/53/B/NZ9/00614), “Determination of the effect of biofortification in iodine and selenium and the application of salicylic acid on the health-promoting quality of selected herbal plant species including post-harvest processing”.