inter-taxa differences in iodine uptake by plants: implications for food quality and contamination

Although iodine is not essential for plants, they take it up readily and, in foodchains, are significant sources of iodine for organisms with an essential requirement for it. During several nuclear accidents radioiodine has been an important component of releases of radioactivity and has caused serious contamination of foodchains. Differences in iodine uptake by different plant taxa are, therefore, important to nutritional and radioecological studies. Using techniques we have developed for a range of other elements, we analyzed inter-taxa differences in radioiodine uptake by 103 plant species and between varieties of two species, and analyzed them using a recent, phylogenetically-informed, taxonomy. The results show that there are significant differences in uptake above and below the species level. There are significant differences between Monocots and Eudicots in iodine uptake, and, in particular, hierarchical ANOVA revealed significant differences between Genera within Families. These analyses of the taxonomic origin of differences in plant uptake of iodine can help the prediction of crop contamination with radioiodine and the management of stable iodine in crops for nutritional purposes.