An investigation on anatomical and mechanical properties of vascular bundles in Date palm (case study: Ahvaz countryside)

The main goal of this work was to evaluate the importance of vascular bundles on the physical and mechanical properties of date palm. To prepare experimental samples, two trees (Phoenix dactylifera) with the average diameter of 47 cm were freshly cut from Ahvaz countryside in Khoozestan Province. Cubic samples with dimensions of 2 cm (tangential) × 2 cm (radial) × 2 cm (longitudinal) were taken from different heights of date palm trunk (2, 5 and 7 meter). The anatomical (number, diameter and cross-cut area of single vascular bundles), physical (density) as well as mechanical properties (vascular bundles tension strength and modulus of elasticity) were studied. The results showed that the calculated total area of vascular bundles per 400 mm2 was maximum for samples near the bark (33% of total area) and the value gradually decreased to 27% for specimens around the pith. The number of vascular bundles increase was observed while moving from the pith to the bark. The same variation also attained when the height of date palm stem increased. But for the average values of single vascular bundles diameter and cross-cut area, no regular trend of increase or decrease was observed. For mechanical properties of vascular bundles, the results revealed that tensile strength and modulus of elasticity were greater for specimens close to the pith in comparison with the values of samples near the bark. Finally the highest correlation was found between mechanical properties of vascular bundles and the position of them in transversal direction of date palm stem.