Figure 4

Hierarchical cluster analyses within gene groups uniquely induced by rhizotoxic ion treatments ( I ₉₀ ). Gene groups for Al ion (A), NaCl (B), Cd ion (C) and Cu ion (D) were selected by comparative microarray analysis (Figure 3) and were separately analyzed with a cluster program (see Methods) using the ratio of fold change (FC of other stressor/FC of particular stressor). The ratios of fold change of genes are indicated by color in each panel. Relatively specific clusters are enlarged and the names of genes are indicated for each treatment. Pearson's correlation coefficients were shown in each panel. The enlarged clusters are specific to the stressor than other sub-groups (see Additional file 5).