Steady-state transcript accumulation for cdc2, Act2 and three kinase genes throughout the surveyed organs (indicated at the bottom of the figure). After determination of RTqPCR primers efficiency and generation of standard curves, RTqPCR analysis was performed for cdc2, Act2, and for two poplar MPKs as well as for one poplar MKK. Twelve nanograms of cDNA were used in each RTqPCR reaction. Results are expressed in number of specific transcripts per ng of total RNA. Values represent the mean of six independent reactions (two repeats for each of three independent samples). Cts were determined using single fluorescent readings that were taken after each cycle.