|Funk, C. - UNIV. OF HAMBURG GERMANY|
Submitted to: American Society of Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: April 30, 2007
Publication Date: November 4, 2007
Citation: Grabber, J.H., Mertens, D.R., Funk, C., Ralph, J. 2007. In-vitro fermentability of cell walls as influenced by lignin composition and cross-linking [abstract]. In: American Society of Agronomy Abstracts. American Society of Agronomy Annual Meeting, November 4-8, 2007, New Orleans, Louisiana. 2007 CDROM. Technical Abstract: We assessed how diverse modifications in lignin composition and reductions in ferulate-lignin cross-linking influence the degradability of cell walls. Cell walls from nonlignified maize cell suspensions were artificially lignified with varying ratios of normal monolignols (coniferyl and sinapyl alcohols) and with monolignols plus unusual lignin precursors identified in some types of normal, mutant, and transgenic plants. Cell walls with normal or reduced feruloylation were also lignified with normal monolignols plus varying levels of sinapyl p-coumarate, the presumed precursor of p-coumaroylated lignins in grasses. Lignified cell walls were incubated in vitro with rumen microflora and then nondegraded structural carbohydrates were determined by acid-solubolization and colorimetric analysis. Shifts in normal monolignol composition or incorporation of 5-hydroxyconiferyl alcohol, coniferaldehyde, gamma-acetylated sinapyl alcohol, dihydroconiferyl alcohol, or sinapyl p-coumarate into lignin did not influence structural carbohydrate degradability. Degradability was, however, enhanced by reductions in ferulate-lignin cross-linking. In ongoing work, the kinetics of cell wall degradation will be determined by measuring gas production during in vitro fermentation with rumen microflora.