Publication Date:
2002-11-05
Description:
Summary Cell-wall dehydrogenation polymers (CW-DHP) were prepared by incubating a mixture of soft xylem (differentiating xylem) from Picea abies, coniferin 13C-enriched at the side-chain β-carbon and unenriched coniferin, both with and without the addition of β-glucosidase and glucose oxidase, which causes an in situ polymerisation of the coniferyl alcohol in the cell wall. From difference solid state 13C-NMR spectra between 13C-enriched CW-DHP and unenriched CW-DHP, the bond frequencies involving specifically 13C-enriched carbon can be quantitatively determined. The sub-structures in CW-DHP prepared without the addition of β-glucosidase and glucose oxidase showed more similarity to protolignin than CW-DHP prepared with the addition of extraneous enzymes. The CW-DHP obtained without the addition of enzymes contained 36% β-O-4-derived sub-structures, 44% combined β-β, β-5 and β-1 sub-structures and 20% coniferyl alcohol/coniferaldehyd end groups. After acetone/water extraction of the CW-DHP, the content of β-β, β-5 and β-1 structures decreased by 4%, and the β-O-4 dominating peak increased by 4%. The 13C-enriched CW-DHP material can be used to study lignin reactions in a solid wood matrix, and is also a powerful system for detailed studies on in vivo lignification mechanisms and the effects on lignification conditions on lignin structure.
Print ISSN:
0018-3830
Electronic ISSN:
1437-434X
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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