|Jung, Hans Joachim|
Submitted to: Cell Wall Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 9/2/2001
Publication Date: 9/3/2001
Citation: BOON, E.J., ENGELS, F.M., CONE, J.W., STRUIK, P.C., JUNG, H.G. DEGRADABILITY OF RIND, PITH PARENCHYMA AND PITH VASCULAR BUNDLE CELL WALL TISSUES ISOLATED FROM MAIZE AT THREE DEVELOPMENTAL STAGES. PROCEEDINGS OF THE 9TH INTERNATIONAL CELL WALL MEETING. 2001. P. 246.
Technical Abstract: Two maize varieties were evaluated for cell wall and tissue development, and cell wall polysaccharide degradability. Internode 7 was collected during elongation, cell wall differentiation, and at silage stage. Internodes were divided into top, middle, and base sections. Top and base sections were separated into rind, pith parenchyma (PAR) and pith vascular bundle (VB) tissues. Cell wall composition and in vitro rumen degradabilit of the samples were investigated in detail. Weight proportion of rind in the internode increased from ~50% in the elongating stage to ~75% in silage stage. The remaining weight was roughly equally divided between VB and PAR in the last two developmental stages. Klason lignin and xylose levels were significantly lower in PAR than in rind or VB. Glucose levels in PAR were significantly higher than in the other tissues. Levels of arabinose, galactose, mannose and uronic acids were highest in PAR, lower in VB, and lowest in rind tissues. Arabinose, mannose, and to a lesser degree galactose levels, were highest in the base of elongating internodes, in both rind and pith. Uronic acids were highest in basal pith tissues of elongating internodes. Significant differences in composition were also found between upper and basal parts of the internode and between developmental stages. Results show a decrease in 24-h degradability of rind tissues from 80% to 60% from the elongation to the differentiation stages of development, and to 43% at silage stage. Basal tissues were significantly more degradable than upper tissues. Significant effects of developmental stage were also visible after 96 h of degradation, with average total polysaccharide degradability decreasing from 73% at the differentiation stage to 59% at silage stage.