Barbara GHISLAIN

 Among other things, the wood has a motor function for the tree, allowing it to be held vertically, or even to stand upright if necessary. Tension wood fulfils this motor function in angiosperms. This tissue develops on the upper surface of an inclined axis and generates high tensile stresses capable of bending a trunk upwards. In the majority of species, the anatomy of tension wood is characterised by a gelatinous layer (G layer) lignified in the fibre wall, although the literature has focused on the study of tension wood with a non-lignified G layer. Tension stresses are generated in the G-layer during cell maturation. In a small number of species, the G layer is absent from tension wood and the high tensile stresses are generated by the interaction of the wood with the bark. Although tensile stress is generated in separate compartments (wood and/or bark), these two mechanisms for generating tensile stress have similar recovery efficiencies in the juvenile stage. However, these two mechanisms are associated with different construction costs. The results of this study open up new avenues of research, particularly into the functional role of lignin in the G layer.