5. Content of Lignin Subunits in SKL, HKL, and OL before (Pristine) and after (Reduced) Sodium Tetrahydroborate Reduction (% of G₂ ¹³C–¹H unit) .

		SKL		HKL		OL
		pristine	reduced	pristine	reduced	pristine	reduced
oxygenated signals	A	5	5	6	4	30	38
	B	2	2	0	1	5	6
	C	5	5	7	8	0	0
	VA		4
	D				2
	I	0	4	0	0	0	0
	J	1	0	1	1	0	0
aromatic signals	G2	100	100	39	40	56	42
	G5	117	101	47	49	106	107
	G6	117	101	33	31	30	23
	S2,6			61	60	80	79
	S/G			0.78	0.76	0.71	0.70
	H2,6	6	6			7	7
	T6					7	7
	T′2,6					6	7
	pCE2,6					6	6
	FA7					10	10

^aA: aryl-glycerol-β-aryl ether, B: phenylcoumaran, C: resinols, I: cinnamyl alcohol, J: α-etherified lignin-carbohydrate complexes, VA: α-carbon in vanillic alcohols, D: α,β-diaryl-glycerol; G: guaiacyl ring, S: siringyl ring, H: p-hydroxy-phenyl ring; T: tricin, pCE: p-coumaric acid esters; FA: ferulic acid esters.