Fig. 3

Total non-protein thiols (NPTs) in the roots. a Rice plants were exposed for a 10-day period to increasing Zn external concentrations (from 0.1 to 10 μM), in the absence (white bars) or presence (grey bars) of 0.1 μM Cd²⁺. b Rice plants were exposed for a 10-day period to different Cd concentrations (from 0 to 1 μM) in the presence of 1 μM Zn²⁺. NPT levels are expressed as GSH equivalents. Bars and error bars are means and SE of three experiments run in triplicate (n = 9). Different letters indicate significant differences between treatments (P < 0.05). Asterisks indicate significant differences between plants exposed or not to 0.1 μM Cd²⁺ (P ≤ 0.001). DW, dry weight