Different chemical forms of Pb and its distribution in different tissues of radish. Lm-200, Rm-200, Sm-200, and LRm-200 were leaves(L), roots(R), skins (S), and lateral roots(LR) of NAU-XLM treated with 200 mg/L Pb(NO3)2; Lm-500, Rm-500, Sm-500, and LRm-500 were leaves, roots, skins, and lateral roots of the NAU-XLM treated with 500 mg/L Pb(NO3)2; Lt-200, Rt-200, St-200, and LRt-200 were leaves, roots, skins, and lateral roots of the NAU-XHT treated with 200 mg/L Pb(NO3)2; Lt-500, Rt-500, St-500, and LRt-500 were leaves, roots, skins, and lateral roots of NAU-XHT treated with 500 mg/L Pb(NO3)2. Residue represents Pb concentration in residue; F-ethanol represents ethanol-extractable form, inorganic Pb including nitrate/nitrite, chloride; F-dH2O extracting water-soluble Pb of organic acid and Pb(PO4)2; F-HAC represents HAC- extractable form, undissolved lead phosphate including PbHPO4 and Pb3(PO4)2; F-NaCl extracting pectates, protein integrated Pb; F-HCl represents HCl- extractable form, extracting lead oxalic. All abbreviations ending with “m” refer to NAU-XLM and “t” to NAU-XHT, “R” to root and “LR' to lateral root, “S” to skin and “L” to leaf.