Proanthocyanidin contents in Bracken and Setaria grown in the pastures.

(A) Condensed tannins were solubilized by acid butanolysis as described by Pang et al. [44]. Epicatechin was used as a standard to calculate the monomeric units of the proanthocyanidins. “Control” and “UV” are samples from the greenhouse. Numbers are indicating the elevation of field-grown plants in m a.s.l. The graph shows the mean ± SEM of at least three independent biological replicates. The letters a, b and c indicate the level of significant differences (p ≤ 0.05) towards each other. Significance was calculated by ANOVA followed by Tukey’s pairwise comparisons. Cross-sections of a Bracken frond (B) and a Setaria leaf (C) were stained with a solution of 1% DMACA and inspected under a light microscope after washing out surplus staining solution with water. Blue color indicates insoluble proanthocyanidin accumulation. A representative example of n≥3 experiments is shown.