Figure 4. Twofold and threefold screw xylan have distinct carbon 1 shifts.

An overlay is shown of ¹³C PDSD NMR spectra of wild type (CP-PDSD 1 s mixing time) and irx3 (DP-PDSD, 1.5 s mixing time) never-dried Arabidopsis stems. Wild-type and irx3 show two distinct xylan conformations: in wild-type plants Xn1^2f resonates at 105.2 p.p.m., whereas in irx3 Xn1^3f is at 102.6 p.p.m. These long mixing time spectra were recorded at a ¹³C Larmor frequency of 213.8 MHz and a MAS frequency of 12 kHz.