Figure 2.

NMR. Partial short-range ¹H-¹³C HSQC NMR spectra from the whole CWs of 3.5-month-old wild-type (WT) and CAD1-deficient poplar lines, as indicated in the top left corner of each plot. A, Aldehyde region. B, Lignin aromatic and double bond region. C, Lignin oxygenated aliphatic and polysaccharide region. The colors of the contours correspond with the structures drawn at the bottom of each plot. In B, the signals of the S, S*, G, X2_G′, and H units sum to 100%. The signal of pB is given in parentheses, because it is left out of this sum. pB is not an actual lignin unit but a decoration found mainly on S units derived from lignification using monolignol p-hydroxybenzoates (Lu et al., 2015). Similarly, in C, X1 is not always a pure peak and, as an end group, is overrepresented in these spectra; it is reported on the A + B + C = 100 basis. n = 4 for the wild type and n = 3 for each CAD1-deficient line, and representative spectra are shown. Level data are from uncorrected integrals only.