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 thes e values. A residual maximum likelihood (REML) analysis was performed on da ta from 14 published studies, after these data were log-transformed to adju st for between-study differences in means and variances. There were two ord ers of magnitude difference between the lowest and highest relative shoot C s concentration of the 136 taxa. Hierarchical nested analysis of variance r evealed more than 40% of the variation in relative shoot Cs concentration w as at the level of family or above. Dicotyledons (Magnoliopsida) had three- fold higher mean relative shoot Cs concentrations than monocotyledons (Lili opsida) whilst differences were also observed at lower taxonomic levels. Th e Caryophyllidae had the highest mean relative shoot Cs concentration among superorders; this group of plants contains many halophyte taxa and crop de rivatives (e.g. beets, quinoas, buckwheats and amaranths). This method coul d inform soil-to-plant Ca transfer models and identify taxa with high Cs ac cumulation patterns that may have phytoremediation potential. The method re ported could be used to study the accumulation of other elements in plants. (C) 1999 Elsevier Science Ltd. All rights reserved.