Arsenic accumulation analysis
Shoot and root samples from plants grown on media containing 20 µM AsIII for 3-weeks were harvested separately. The samples were washed with 10 mM sodium-EDTA to remove excess As adsorbed on surface and then rinsed twice with DI water. The samples were then dried at 70oC for 48 hours. Dried samples were weighed, roughly crushed, and digested using concentrated nitric acid (15.8N) and 30% hydrogen peroxide (H2O2) on a heat block digester at 115oC for 45 minutes. Digested samples were then diluted and analyzed for arsenic using ICP-MS (ICPMS-2030, Shimadzu Corporation, Nakagyo-ku, Kyoto, Japan). Translocation factor from root to shoot was calculated using this formula: TF = As concentration in shoot/ As concentration in root