Fig. 4

A Expression thermography of PAP, ACP and SPX genes in phosphorus response genes; B Thermograms of key genes for organic acid synthesis and metabolism; C Thermograms of PHT gene expression. The color bar indicates the expression levels [represented as log2(RPKM means)]; red indicates high expression level, blue indicates low expression level, and white indicates RPKM = 0; D Expression analysis of differentially expressed genes in PHTs gene family of the Chinese fir roots under different phosphorus concentrations (high Pi supply - HP, Pi deficiency - LP and Pi starvation -NP) for 3 and 30 days. The experiments were repeated three times on three biological replicates of each treatment (n = 3). Values are means ± SD. Bars followed by different letter(s) indicate significant difference at P < 0.01