Figure 4. Effects of cinnamic acid on cinnamate 4-hydroxylase (C4H) oxidase activity of soybean roots untreated (C) or treated with 1.0 mM cinnamic acid (CA), 0.1 mM piperonylic acid (PIP) and 1.0 mM cinnamic acid plus 0.1 mM piperonylic acid (CA + PIP).
Values (n = 4 ± SE) marked with different letters are significantly different (P ≤ 0.05, Scott-Knott test).