The amiR-cad1 transgene results in a brown midrib phenotype. For each line, a leaf was removed from the second node and imaged using darkfield microscopy. (A) empty vector control, (B) amiR-cad1-1, and (C) amiR-cad1-8. The brown pigmentation of the leaf midrib of transgenic CAD-downregulated plants was consistently observed in new leaves over time. The midrib of the empty vector control appeared green and no difference in pigmentation was observed. COMT-downregulated transgenics looked similar to control.