Dynamic characterization of iodine uptake in vegetable plants

Hydroponics experiment was carried out to investigate iodine(iodide or iodate)uptake in celery and Chinese cabbage.Iodine uptake in both plants increased rapidly within a short time treatment(60 min)and then decreased gradually.With low iodine concentration(0-0.50 mg/L)treatments,characteristics reminiscent of Michaelis-Menten kinetics was observed via relationship of concentration of iodate or iodate and the the iodine uptake rate.Iodate uptake was inhibited by oxidative phosphorylation inhibitor 2,4-dinitrophenol when the plants were treated with less than 0.50 mg/L iodate,whereas no significant inhibit was observed and the iodine uptake rate was linearly correlated to the iodine concentration when iodate concentration was above 0.50 mg/L,which suggested that plant can actively uptake iodate when under low concentration.As compared to Chinese cabbage,celery showed a greater iodine uptake.The iodine content in the vegetable edible parts increased in the first week then decreased as the iodine was added only once at the beginning,whereas the iodine content of edible parts of vegetable increased constantly when continuously supplied with iodine.When treated with low iodine concentration(0.50 mg/L),iodine uptake in both plants were reduced by chlorine,but no significant effect of chlorine on iodine uptake in the plants treated with high iodine concentration.The iodine accumulation coefficient in both plant was decreased when the iodine concentration in the media increased.The iodine distribution in both plants was rootleafstem.