Table III.

Determination of coniferaldehyde units in soluble lignin fractions by the Wiesner reaction

Sample		Lignin Fraction		Coniferaldehyde Units in Lignin Fraction
Line	Wood coloration	Isolation yield	G in β-O-4	wt (%)	μmol g−1
		% KL	%
Control	White	37	26	0.45	25.3
ASCAD21	Red	50	27	0.30	16.8
ASOMT2B	Pale pink	43	56	1.13	63.5
ASCAD21 × ASOMT7	Red	59	63	1.08	60.6

These lignin fractions were isolated by solvent extraction (dioxane:water, 9:1, v/v) of 1-year-old extract-free stems after ball milling and cellulase hydrolysis, which were then purified by precipitation in water. The isolation yield of the recovered lignin fractions is expressed as a weight percentage of total lignin. KL, Klason lignin. The percentage (molar) of G units in β-O-4 lignin structures was determined by thioacidolysis.