<p><b>(A), (A’)</b><i>TCSn</i>:<i>VENUS-H2B</i> expression in untreated roots; transmitted light and VENUS emission (A)) and VENUS emission only (A’)); white arrow head in A’: metaxylem, gray arrow head in A’: QC; seven independent transgenic lines were examined and exhibit a similar expression pattern. <b>(B)</b> Quantification of <i>TCSn</i>:<i>VENUS-H2B</i> expression by the mean gray value of the region marked by red box in C); mean gray value normalized to the PBS control; significance was determined using the two-tailed Student’s t test, ** = p<0.001. <b>(C)</b> Representative pictures of <i>TCSn</i>:<i>VENUS-H2B</i> expression in root meristems upon 24 h of cytokinin treatment according to the captions; PBS without hormone was used as control; three independent transgenic lines were examined; the experiment was performed three times; n = 8–31 per treatment. <b>(D)</b> Magnification of the stem cell niche and root cap of roots upon treatments indicated by the captions; expression in the cortex/ endodermis initials, the DSCs, the QC layer adjacent to the root cap and the epidermis initials (PBS: 0/21 roots, 1 μM 6-BA: 1/9 roots, 10 μM 6-BA 8/18 roots, 1 μM t-Z 2/9 roots, 10 μM t-Z 5/8 roots); the root cap border is marked with a white frame; for a better comparison between samples, roots were cleared before microscopy (C), D), E)); scale bars 100 μm.</p
