Marking by introducing iodine into lettuce [Lactuca sativa] grown in hydroponics to certify the provenance

• Published in: Journal of Science and High Technology in Agriculture (Japan) Vol. 19; no. 3; pp. 137 - 140
• Main Authors: Bai, G.(Saga Univ. (Japan). Faculty of Agriculture), Nakahara, T, Murase, H, Ueno, D, Akao, S, Someya, T, Inoue, K
• Format: Journal Article
• Language: Japanese
• Published: Japanese Society of Agricultural, Biological and Environmental Engineers and Scientists 01.09.2007
• Subjects: CULTIVO HIDROPONICO; CULTURE HYDROPONIQUE; HYDROPONICS; IODE; IODINE; LACTUCA SATIVA; lettuce; marking system; traceability; YODO
• ISSN: 1880-2028; 1880-3563
• DOI: 10.2525/shita.19.137

It was studied whether iodine could be used as a marker element to certify the provenance of vegetables grown hydroponically. Two species of lettuce (Lactuca sativa L., cv: Red-fire and Rakuten) were cultivated in nutrient solution containing potassium iodate (KIO3) or iodide (KI) at 4 levels of iodine concentrations (0.05, 0.10, 0.20 and 0.50 mg/l) for 24 days. Lettuce grown under all treatments with potassium iodate (KIO3) and iodide (KI) showed favorable growth similar to the control. In both treatments of potassium iodate (KIO3) and iodide (KI), concentrations of iodine in the tops of lettuce were linearly increased in proportion to the increase of concentration in nutrient solution. In addition, the amount of iodine contained in 470g of treated lettuce (amount recommended by the Ministry of Health and Welfare of Japan for daily consumption by adults) in treatments with a concentration range of 0.05-0.20 mg/l were obviously lower than the Acceptable Daily Intake (ADI: 3.00 mg) and were remarkably higher than the natural abundance (about 0.22 mg/kg DW). These results suggest that iodine could be used as a marker element to certify the provenance of lettuce grown hydroponically when lettuce is cultivated using a nutrient solution within a suitable concentration range.