Figure 8. cAMP pathway might be involved in H₂S-alleviated Cd toxicity.

Fresh weight of 10 roots (A), TBARS accumulation (B), GR1 (C), Cu,Zn-SOD (D), APX1 (E), and GPX (F) gene expression in alfalfa seedling roots upon Cd stress. Seedlings were pretreated with or without 100 µM NaHS, 50 µM 8-Br-cAMP (8Br), 2 mM PAG, 200 µM alloxan (All), 500 µM IBMX, 1 mM DDA alone, or the combination of treatments for 6 h, and then exposed to 200 µM CdCl₂ for 72 h (A), 24 h (B) and 12 h (C–F). The expression levels of corresponding genes analyzed by real-time RT-PCR are presented as values relative to the control, normalized against expression of two internal reference genes in each sample. Values are means ± SD of three independent experiments with three replicates for each. Bars denoted by the same letter did not differ significantly at P<0.05 according to Duncan's multiple range test.