(a)   36 Pa CO2
(b) 72 Pa CO2
Figure 3: Total ion chromatogram showing changes of an unidentified compound (Unk-21.03) that decreased in soybean apices in response to CO2 enrichment. Chromatograms were prepared with similar amounts of extracts of soybean apices from the ambient (a) and elevated (b) CO2 treatments. The unidentified compound eluted from the column at 21.03 minutes and is marked with a descending arrow. Values are means ± SE (n = 8).