Dynamic absorption of iodine-125 in Chinese cabbage (Brassica chinesis L.)
青菜(Brassica chinesis L.)对碘动态吸收的同位素示踪

Iodine has been long known as an indispensable element in the synthesis of thyroid hormones. Severe iodine deficiency in diet leads to iodine deficiency disorders in humans. Here we propose a new method of iodine supply by cultivating iodized crops. We studied the dynamic absorption pattern of 125I by Chinese cabbage (Brassica chinesis L.) from liquid media, using the isotope tracer method. The results showed that 125I is absorbed quickly by roots and generally transported to shoots. The iodine accumulation capacity in different tissue types ranks as root>stem>leaf. More 125I was absorbed during the day than during the night in stems, but opposite in the leaves. Analysis on leaves from different nodes reveals a differential absorption pattern that 125I accumulates more in the upper leaves than in the lower leaves. These results suggest that active and passive 125I absorption mechanisms may coexist in liquid cultivated Chinese cabbage. After 120 hours, most of 125I in the liquid media was absorbed by Chinese cabbage and some was lost through volatilization. This study provides initial scientific basis for cultivating organic iodized crops as an alternative to iodized salt to reduce iodine deficiency.