Figure 6.

Expression profiles of Populus DREB genes across different tissues. Heat map showing hierarchical clustering of 75 PtrDREB genes across various tissues analyzed. The Affymetrix microarray data were obtained from NCBI Gene Expression Omnibus (GEO) database under the series accession number GSE16422. ML: mature leaf; YL: young leaf; R: root; I: internodes; N: nodes. Color scale represents log2 expression values, green represents low level, and red indicates high level of transcript abundances.