A method to assess taxonomic variation in shoot caesium concentration among flowering plants

A method was developed to obtain relative shoot caesium (Cs) concentration data from the literature and assess the influence of plant taxonomy on these values. A residual maximum likelihood (REML) analysis was performed on data from 14 published studies, after these data were log-transformed to adjust for between-study differences in means and variances. There were two orders of magnitude difference between the lowest and highest relative shoot Cs concentration of the 136 taxa. Hierarchical nested analysis of variance revealed more than 40% of the variation in relative shoot Cs concentration was at the level of family or above. Dicotyledons (Magnoliopsida) had three-fold higher mean relative shoot Cs concentrations than monocotyledons (Liliopsida) whilst differences were also observed at lower taxonomic levels. The Caryophyllidae had the highest mean relative shoot Cs concentration among superorders; this group of plants contains many halophyte taxa and crop derivatives (e.g. beets, quinoas, buckwheats and amaranths). This method could inform soil-to-plant Cs transfer models and identify taxa with high Cs accumulation patterns that may have phytoremediation potential. The method reported could be used to study the accumulation of other elements in plants.