Table IV. Cell wall characteristics.
The cell wall residue (CWR) expressed as a percentage of dry weight was determined gravimetrically after a sequential extraction (n = 6). Lignin content was determined with the Klason method and expressed as percentage of CWR (n = 3). Lignin composition was determined with thioacidolysis (n = 6). The sum of H, G, and S is expressed in μmol g−1 Klason lignin. The relative proportions of the different lignin units were calculated based on the total thioacidolysis yield (including the minor nonconventional lignin units). S/G ratio was calculated based on the absolute values for S and G. β-O-4-FA-I, G-CH=CH-COOH; β-O-4-FA-II, G-CHR-CH2-COOH; bis-β-O-4-FA, G-CHR-CHR2 (R = thioethyl). Cellulose was expressed as a percentage of CWR (n = 6). Values given are averages ± sd. Different letters represent significant differences at the 0.05 significance level (Dunnett-Hsu adjusted Student’s t test).
| Line | CWR | Lignin Content and Composition |
Crystalline Cellulose | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Klason Lignin | H + G + S | H | G | S | S/G Ratio | β-O-4-FA-I | β-O-4-FA-II | bis-β-O-4-FA | |||
| % | % CWR | μmol g−1 | % | % | % | % | % | % | % CWR | ||
| Wild type | 78.5± 1.3 a | 18.0± 0.9 a | 23.6± 3.5 a | 1.8± 0.6 a | 71.5± 1.2 a | 26.6± 0.9 a | 0.37± 0.02 a | 0.03± 0.03 a | 0.02± 0.00 a | 0.09± 0.01 a | 44.7± 2.2 a |
| ccr1-6 | 69.4± 2.0 b | 9.5± 1.0 b | 8.9± 1.9 b | 5.5± 2.9 b | 70.5± 1.5 a | 21.9± 3.3 b | 0.31± 0.05 b | 0.35± 0.25 b | 0.40± 0.13 b | 1.34± 0.76 b | 34.4± 3.2 b |
| ccr1-6 ProSNBE:CCR1 line 1 | 74.2± 1.7 c | 9.7± 0.5 b | 6.9± 1.7 b | 5.5± 2.7 b | 77.8± 2.6 b | 14.2± 1.5 c | 0.18± 0.02 c | 0.41± 0.26 b | 0.46± 0.09 b | 1.56± 0.92 b | 38.6± 2.5 b |
| ccr1-6 ProSNBE:CCR1 line 2 | 73.6± 1.2 c | 9.9± 0.3 b | 7.4± 1.5 b | 5.5± 1.7 b | 78.1± 2.7 b | 14.0± 2.3 c | 0.18± 0.04 c | 0.38± 0.17 b | 0.54± 0.12 b | 1.45± 0.58 b | 35.5± 2.3 b |