CELL WALL-BOUND PHENOLS IN DATE PALM LEAVES AND ROOTS. IDENTIFICATION AND HISTOCHEMICAL LOCALIZATION.

Phenols bound to the cell walls of date palm (Phoenix dactylifera L.) leaves and roots were extracted by alkaline hydrolysis of dry residue after extraction of phenol soluble forms.
Three phenolic acids were identified : ferulic (FA), p-coumaric (PCA) and p-hydroxybenzoic (PHBA) acids.
Quantitative analysis showed a significant difference between leaves and roots concerning the relative abundance of FA and PCA. Leaf cell-walls accumulate an amount of PCA which has been found to be 5 times higher than FA. In the contrary, the level of FA bound to root cell walls was 7 to 12 times higher than PCA. Results obtained by ultraviolet fluorescence microscopy indicated that FA is bound to walls of parenchyma and phloem cells, while PCA is more abundant in sclerenchyma and xylem cell walls.
It seems that the difference in the distribution of phenolic acids is in relation with the histological structure of the palm leaves and roots.
So, the abundance of lignified cells (sclerenchyma and xylem) in leaves and unlignified cells (parenchyma) in roots may explain the relative dominance of PCA and FA respectively.

International Symposium on Natural Phenols in Plant Resistance

A. ZIOUTI, E. EL BOUSTANI, J.J. MACHEIX

https://doi.org/10.17660/ActaHortic.1994.381.34