Figure 4. Relative fold induction of gene expression in Arabidopsis root tissue treated with gold.

Plants were grown hydroponically for six weeks then the medium was replaced with 25 or 50/L gold, as K(AuCl₄) for 6 h, and then RNA extracted from roots for qPCR analysis. The data were normalized to the Arabidopsis ACTIN2 gene and relative fold induction calculated using the ΔΔCt method [36]. Results are the mean from four biological replicates ± SD, * denotes significantly (p<0.05) more upregulated than untreated samples.