A large number of date palm (Phoenix dactylifera L.) trees growing in Egypt provide a large quantity of non-fruit materials, specially frond midrib.
The properties of DPLM (palm frond) products as biological raw material are mainly determined by the structure of the frond. The anatomical structure of DPLM and variability of structure quantitatively (fiber length, number of vascular bundles, percentage of fiber tissue, distribution of vascular bundles in different locations and thickness of periphery vascular sheath) of two local varieties (Baladi and Seiwi) was studied.
The anatomical structure of palm DPLM corresponds to the general structure of stems of monocotyledons. However, near the periphery, the bundles are smaller, more numerous, circular in cross section and with one or two metaxylem tissue and fiber sheath almost united with the sclerenchyma of the cortex.
Across the midrib, three zones of vascular bundles can be distinguished, the peripheral, transitional zone and inner zone. In the first and second zone, the fiber sheath is thick, and the vascular bundles are numerous with small parenchyma cells between them. The third zone is the broadest, where the bundles reach their highest diameter. The average width of the periphery and transition zones across the midrib is 1.265 mm. Fiber tissue percent is higher in the periphery and transition zone (38%) than in the inner or central zone (10%).
The average fiber length of Balady DPLM (1.366 mm) was statistically higher than Seiwi DPLM (1.288 mm). Also the number of bundles per mm2 and fiber tissue percent were higher in Baladi midribs than in Seiwi. However, there are no significant differences between the Seiwi and Baladi palm species in vascular bundle diameter.
Key words: date palm leaves midrib, palm fronds, anatomical structure, anatomical variations.
Correspondence: Megahed Mabrouk Megahed, Forestry and Wood Technology Department, Faculty of Agriculture, Alexandria University, El-Shatby, Alexandria, Egypt