Microfibril orientation in differentiating and maturing fibre and parenchyma cell walls in culms of bamboo (Phyllostachys viridi-glaucescens (Carr.) Riv. & Riv.)

Results of trials using chemical and enzymatic wall extractants for the rem oval of matrix materials for in situ observations of newly deposited microf ibrils are described. Observations were then made of the orientation of mic rofibrils on the inner walls of differentiating and maturing fibres and par enchyma cells under the FESEM. Orientation changes were similar in both cel l types. During very early primary wall development, deposition of microfib rils was in more or less axial alignment, which was later superseded by mic rofibrils in transverse orientation (90 degrees to the long axis). A transv erse orientation of microfibrils remained throughout much of primary wall s ynthesis, until an abrupt shift occurred to a sloped orientation during lat e primary wall synthesis. Microfibrils of the first secondary wall layer we re in axial alignment or steeply sloped. Tn subsequent secondary wall depos ition there was an alternation between a transverse and a sloped or axial a lignment in maturing fibres and parenchyma cells. (C) 2000 The Linnean Soci ety of London.