Figure 5.

Analysis of tissue-specific expression of PIN, AUX/LAX, and ABCB transcripts. Presence or absence of transcripts of genes coding for putative auxin transport proteins in the cortex, secondary phloem, cambial zone (i.e., initials and mother/daughter cells), and mature secondary xylem of Populus tremula × alba as determined by RT-PCR. Consensus of four biological replicates is shown, where GRAY = PRESENT, WHITE = ABSENT, and CROSS-HATCHED = VARIABLE among biological replicates. Samples were taken from the base of 6-month-old trees during active growth, approximately 100 internodes down from the top of the tree at a diameter of about 2 cm.