Expression of CLE209 and CLE210 in planta in xylem, phloem, root and differentiating pine tracheary element cultured cells. A. and B. Quantitative PCR analysis of CLE209 (dark grey bars) and CLE210 (light grey bars). A. Expression levels of CLE209 and CLE210 in xylem, phloem and root cells. B. Timecourse of expression levels of CLE209 and CLE210 in the in vitro-cultured P.radiata tracheary element differentiation system. Error bars represent standard deviations among three biological replicates. Student’s t-test analysis of the data revealed that all expression differences were significant to a 95% confidence interval except for the CLE209/CLE210 expression (xylem samples), for Day 4/Day 8 and Day 6/Day 10 (CLE209 expression in the tracheary element differentiation experiments) and for Day 8/Day 10 (CLE210 expression in the tracheary element differentiation experiments).