Histochemical analysis of lignin in stem. Cross sections of stems at the first internode of developmentally equivalent plants were dissected when the flag leaf was 4 cm below the spike. (A,D) wildtype, (B,E) amiR-cad1, and (C,F) amiR-comt4. Wiesner reagents stain lignified tissue in a concentration-indicative manner; heavily lignified tissue stains dark red, while areas with less lignin stain orange-yellow (A,B,C). The Mäule reagent stains S lignin; a shift from red to brown-yellow is representative of a decrease in S lignin (D,E,F).