Cell wall phenolics and digestibility of normal and brown midrib maizes indifferent stem sections and across maturity stages

The concentration of phenolic acids and in situ disappearance of cell wall (CWISD) of normal maize and bm1, bm2, bm3 and bm4 mutants were evaluated in whole stem and stem sections at the silking and silage stages. At the silk ing stage, the CWISD of bm1 was similar to that of normal maize while that of bm2, bm3 and bm4 was greater; p-coumaric acid and lignin concentrations were lower in the mutants while ferulic acid varied little. At the silage s tage, the composition was slightly altered but the CWISD of the mutants was notably reduced, possibly because of condensation reactions occuring with ageing. The mid-internode was the most similar in composition and degradabi lity to the whole stem. (C) 1999 Society of Chemical Industry.