Endogenous phenolic contents, peroxidase and polyphenoloxidase activities in date palm (Phoenix dactylifera L.) offshoots related to rooting ability

Offshoots from three cultivars of date palm showed different rooting ability, in response to the same root inducing treatment (25 mM indole butyric acid), under misting system. Offshoots from Mejhoul rooted easily and produced numerous roots, while those from Khalt rooted poorly and produced fewer roots. No relationship was found between soluble and ionically bound peroxidase and polyphenoloxidase activities and phenolics level, determined spectrophotometrically in the offshoot leaves prior to the auxin application, and the rooting ability of these cultivars. However, changes of these parameters during the first month of culture were correlated with the rooting ability. In the well rooting cultivar, the soluble peroxidase activity showed a minimum on the 4th day and a maximum on the 10th day, while phenolics level and polyphenoloxidase activity showed an inverse trend. In the poorly rooting cultivar, these parameters changed weakly.