An investigation of cellular distribution of manganese in hyperaccumlator plant Phytolacca acinosa Roxb. using SRXRF analysis

Phytolacca acinosa Roxb. (P. acinosa) is a recently discovered mangane se hyperaccumulator plant from southern China. It is a good candidate for phytor emediation of manganese(Mn) polluted soil for its high biomass and fast growth. Knowledge of the tissue localization and identification of heavy metals can prov ide essential information on metal toxicity and bioaccumulation mechanisms. Sync hrotron radiation X-ray fluorescence spectroscopy (SRXRF) microprobe was used in this study to investigate the cellular distributions of Mn and other elements i n root, stem, leaf, petiole and midrib of P. acinosa. The highest Mn content was found in the vascular tissues of root, stem, petiole and midrib. Cortex in root played a key role in Mn absorption and Mn was limited in the vascular bundle du ring the process of transportation in stem. Moreover, Mn content in leaf epiderm is was higher than that in mesophyll, which suggested that the sequestration of Mn in leaf epidermis might be one of the detoxification mechanisms of P. acinosa . The significance of other elemental (such as P, S, K, Ca, Fe, Zn and Cu) distr ibution patterns and the correlation with Mn were also discussed.