DR5::GUS reporter gene expression in
leaf primordia exposed to 2,4-D. First rosette leaf
primordia were incubated in culture medium containing 1
μm 2,4-D for 5 h, followed by
histochemical detection of GUS activity. Age in DAG: A, 2; B, 3; C, 4.
Scale bars = 50 μm in A and B, 100 μm in C. DIC
optics.