Mechanical stress as stimulus for structurally and chemically altered walls in wood xylem cells

Hamburg

2007

S. 119-128

12 Abb., 34 Lit. Ang.

Artikel aus einer ZeitschriftUnselbständiges Werk

200151618

Cell walls in woody tissues affected by mechanical stress often display structural and chemical modifications. Electron microscopy and UV-microspectrophotometry were used to study modifications in the secondary xylem tissues caused by wounding and exposure to extreme wind. Wounding of hardwoods initiates wall modifications in already differentiated as well as differentiating xylem. Modifications include atypical wall architecture, increase in lignin content, and partial incorporation of phenolic compounds. In spruce trees, exposure to extreme wind often leads to the formation of so called 'Wulstholz' on the compression side of bent trees. Walls of 'Wulstholz' tracheids are mainly characterized by thickening of their secondary walls and also by an increasing lignin content. Modification of cell walls, as a response to mechanical stress, are a part of tree survival strategies.