Figure 1.
2D-NMR HSQC spectra of nonderivatized E. globulus cell wall separated into aliphatic, anomeric and aromatic regions.
Color-coding in HSQC spectrum corresponding to known lignin substructures and polysaccharide units commonly found in plant cell walls. The main structures observed in the aliphatic region are: β-aryl ether units (A), phenylcoumaran units (B), resinol units (C), xylan (Xyl), acetylated xylosyl residues (2-O-Ac-β-D-Xylp and 3-O-Ac-β-D-Xylp), 2-acetylated mannosyl residues (2-O-Ac-β-D-Manp), and glucan (Glc6). The main structures observed in the anomeric region are: cellulose (β-D-Glcp), xylan (β-D-Xylp), acetylated xylosyl residues(2-O-Ac-β-D-Xylp and 3-O-Ac-β-D-Xylp), mannan (β-D-Manp), acetylated mannosyl residues (2-O-Ac-β-D-Manp), arabinan (β-D-Araf) and 4-O-methyl-α-D-glucuronic acid (4-O-MeGlcA). The main structures observed in the aromatic regions are: syringyl (S), oxidized syringyl (Ś) and guaiacyl (G) units.
Table 1.
The ratio of lignin substructures and crystallinity index of heartwood (HW) and sapwood (SW) samples.
Figure 2.
X-ray diffractograms of heartwood and sapwood samples.
(A) Example of eucalyptus species (E. globulus) and reference (lignin) x-ray diffractogram to determine amorphous and crystalline phase. X-ray diffractograms of heartwoods (B) and sapwoods (C) of all hardwood species.
Table 2.
Biochemical composition of extracted biomass samples of heartwood (HW) and sapwood (SW) as determined by two stage acid hydrolysis.
Table 3.
Detailed carbohydrate biochemical composition of extracted biomass samples of heartwood (HW) and sapwood (SW) as determined by HPAEC and Updegraff.
Figure 3.
Canonical variate analysis of FT-NIR spectra of heartwood (A) and sapwood (B) demonstrating clustering of species into district groups.