Identifying new lignin bioengineering targets: 1. Monolignol-substitute impacts on lignin formation and cell wall fermentability

Table 2 Klason lignin, in-vitro ruminal fermentation kinetics^a, nonfermentable polysaccharides (NP), gas reduction per unit lignin (GRL)^b, and nonfermentable polysaccharide accumulation per unit lignin (NPAL)^c for nonlignified and artificially lignified cell walls of maize.

Monolignols	Lignin mg/g	L₁ (h)	k₁ (h^-1)	A(mL/g)	L₂ (h)	k₂ (h^-1)	B(mL/g)	AB(mL/g)	NP (mg/g)	GRL	NPAL
Nonlignified	--	1.83	0.244	298	0.4	0.033	67	365	21	--	--
CA	151	1.95	0.099	231	11.1	0.043	46	277	130	0.589	0.708
CA:EF	154	1.94	0.082	225	14.9	0.037	35	260	162	0.697	0.907
CA:FEG	149	2.44	0.092	231	12.5	0.041	40	271	142	0.647	0.808
CA:FG	149	2.31	0.114	221	9.5	0.040	48	269	122	0.652	0.676
CA:DFG	124	2.33	0.135	251	9.4	0.040	47	299	81	0.544	0.487
CA:DFT	135	2.36	0.117	236	10.3	0.040	43	279	90	0.650	0.508
LSD^d	20	0.51	0.017	23	1.9	0.008	12	30	38	NS ^e	0.163

^aKinetic parameters: lag time (L₁), rate constant (k₁), and volume (A) of gas produced from a rapidly digested pool; lag time (L₂), rate constant (k₂), and volume (B) of gas produced from a slowly digested pool; and total gas volume (AB)
^bGRL calculated as (AB_nonlignified - AB_lignified)/Klason lignin
^cNPAL calculated as (NP_lignified - NP_nonlignified)/Klason lignin
^dLSD, least significant difference (P = 0.05)
^eNS, not significant (P = 0.43).
Cell walls were lignified with coniferyl alcohol (CA) or binary mixtures of CA with ethyl ferulate (EF), feruloyl ethylene glycol (FEG), 1-O-feruloyl glycerol (FG), 1,3-O-diferuloyl glycerol (DFG), or 1,4-O-diferuloyl threitol (DFT).

ISSN: 1471-2229