Figure 2. Emission of GLVs is stimulated by mechanical wounding, but is suppressed by chewing insects. Gas chromatography-mass spectrometry (GC-MS) ion chromatograms (m/z 67) showing cis-3-hexenol and cis-3-hexenyl acetate in volatile samples collected from control (black line), wounded (red line), and caterpillar damaged (blue line) Arabidopsis plants. Volatiles were captured for 3 h on mini-columns filled with Porapak Q^® 100/120 (Alltech Associates, Inc.) using an open-flow system, bound compounds were eluted with 300 µl of dichloromethane and analyzed by GC-MS.