Oxidative responses and genetic stability of date palm Phoenix dactylifera L. Barhi cv. under salinity stress.

This study was aimed to investigate the oxidative responses and genetic stability of date palm Phoenix dactylifera L. under different irrigation water salinity, date palm off shoots cv. Barhi subjected to different concentrations of NaCl (100, 200, 300 and 400 µM) for 180 days. The obtained results showed that, the date palm responses to salinity stress, this responses was increased of H2O2 level, Peroxidase activity and Malondialdehyde MDA concentration with increase NaCl concentration, while opposite trend with membrane stability index, which H2O2 was increased from(0.73 µM/g) in control to (2.20 µM/g) in 400 µM treatment, MDA was increased from (2.35 nmole/g) in control to (nmole/g) in 400 µM treatment, also peroxidase activity was reached to (39.59 U/min/g) in 400 µM treatment, while was (20.73 U/min/g) in control and Membrane stability index reduction significantly from (81.36%) in control to (64.13%) in 400 µM treatment.  In terms of genetic stability of date palm under salinity stress, the ISSR markers analysis showed that, the high concentrations of NaCl (200, 300 and 400 µM) produced more polymorphic fragments comparison to control treatment, while the DNA profile was identical between control and 100 µMtreatment.Dendogram was generated using similarity indices of ISSR markers showed, the lowest genetic similarity was found between 400 µM NaCl concentration and control and 100 µM treatment, followed with both 200 and 300 µM treatments, which the control and 100 µM treatment was grouped in one cluster, also treatments with 200 and 300 µM grouped in one cluster, while the treatment with 400 µM NaCl separated in cluster. Keywords: ISSR, Genetic stability, Oxidative stress, Peroxidase, MDA, membrane peroxidatio