Uptake and translocation of cesium-133 in napiergrass (Pennisetum purpureum Schum.) under hydroponic conditions

The present study reports the potential remediation of cesium (Cs) using napiergrass, which produces the largest biomass among the herbaceous plants in hydroponic culture containing stable Cs (Cs-133) at concentrations of 50, 150, 300, 1000, and 3000 μM using cesium chloride (CsCl), with 0 μM Cs as a control concentration. Plant height was significantly decreased in higher Cs-treated conditions (300, 1000, and 3000 μM Cs) at 7 weeks after treatment (WAT), but tiller numbers tended to increase compared with the control plant. No significant difference was observed in the aboveground dry matter weight in all Cs treatments throughout the study period. Cs content in the roots, leaf blades, and leaf sheaths clearly increased with increasing Cs concentration in the solutions. Cs content in the aboveground parts (leaf blades and leaf sheaths) was consistently higher than in the roots at concentration of 3000 μM. Total Cs contents in the aboveground parts were 6305 and 26,365 mg kg−1 at 7 WAT in 1000- and 3000-μM Cs treatments, respectively. Mean values of transfer factors (TFs) in the aboveground parts were 50 μM=0.78, 150 μM=1.02, 300 μM=0.86, 1000 μM=0.68, and 3000 μM=0.94, respectively at 7 WAT. Due to its high Cs content and high TF in the aboveground parts, napiergrass may be a candidate plant with high potential for phytoremediation of Cs from Cs-137-contaminated soil.

► We examine the potential of remediation of Cs using napiergrass.
► Napiergrass accumulates high concentrations of Cs in its aboveground large biomass.
► No significant difference is observed in shoot biomass in all Cs treatments.
► Strong positive correlations are found between shoot dry weight and Cs content.
► Napiergrass may be a candidate plant with high potential for phytoremediation.