Structural and torsional properties of the Trachycarpus fortunei palm petiole

The Trachycarpus fortunei palm is a good example of a palm with a large leaf blade supported by a correspondingly large petiole. The way in which the material and functional properties of the petiole interact is analysed using engineering and botanical methods with a view to understanding how the petiole functions from a structural standpoint. Initially, the histological aspects of the petiole are analysed at a microscopic level from sections of the petiole taken at regular intervals along its axis, in order to determine the density and location of the vascular bundles. A modified torsion rig was used to measure the torsion and shear stress variation along petiole sample lengths. Knowledge of vascular bundle placement within the petiole sections and their torsional loading characteristics contribute to understanding the petiole function.