Fate of Carbon‐14‐Labeled Cell Walls in Silage Fermentation¹

Abstract

Uniformly carbon‐14 labeled wheat plant cell walls (CW‐UL14C) were combined with ground orchardgrass hay substrate and ensiled in order to determine the contribution of cell walls to silage fermentation end‐products. Eight samples in half‐pint jars were fermented for either 49, 76, 141, 188, 237, 285, 429, or 504 hours. Carbon‐14 activity was measured in water solubles, organic acids, and carbon dioxide. Substantial activity was found in lactic and acetic acid, both of which increased at essentially the same rate initially. Eight percent of the labeled cell wall was hydrolyzed, apparently through bacterial mechanisms. Eighty percent was found in the acids and 4.5% in carbon dioxide. The usefulness of this technique for studying various ramifications of silage fermentation is demonstrated.

The Kinetics of Straw Decomposition in Relation to Its Potential to Produce the Phytotoxin Acetic Acid

“…However these studies have not been combined with an examination of changes in the potential of the straw to act as a substrate for phytotoxin production by micro-organisms. The major potential substrates in straw are the polysaccharide components cellulose and hemicellulose which together contribute 75-80 per cent of the straw dry weight (Goering et al, 1970; Harper and Lynch, 1981).…”