Fig. 5

DNP-enabled 2D CHHC spectra of unlabeled rice stems. The CHHC spectra of unlabeled WT sample are measured with a 1 ms and b 2 ms ¹H-¹H mixing times. c Summary of through-space intramolecular cross peaks. Solid lines denote the cross peaks observable in both 1 and 2 ms spectra, while dash lines indicate the cross peaks that are observed only in the 2-ms spectrum. Arrows are used to indicate whether the cross peaks are bidirectional (e.g., C1-to-C2 and C2-to-C1 cross peaks) or unidirectional (e.g., only from C1 to C2). d Comparison of polysaccharide signals in the 2-ms CHHC spectrum of the unlabeled sample and a 5-ms PDSD spectrum of ¹³C-labeled rice