Figure 2.

a, Stem segment of control aspen with a typical pale-yellow color; b to e, stem segments of transgenic aspen with mottled reddish-brown coloration; f, stem segment of transgenic plant S13 with a reddish-brown coloration throughout; g to l, stem cross-sections of transgenic plants with irregularly colored areas that were intensified to dark red with Wiesner reagent; m to o, serial stem cross-sections of a transgenic plant showing the red-brown color (m) that was intensified into a dark-red color after the Wiesner reaction (n) and the disappearance of the red-brown color after NaBH₄ reduction with a negative response to a prolonged Wiesner reaction (o).