Differential responses of growth, metals accumulation, oxidative stress and Osmo-compatible solutes in the Halophyte Tamarix gallica under Arsenic and Aluminum stress alone or combined with salt

In order to evaluate the ecological risk generated by the heavy metals cumulation in salt-affected soils. The research was carried out in the halophyte Tamarix gallica which is known to thrive under harsh environmental occurrences. The main aim of this work was to study the tolerance and accumulation capabilities of Tamarix gallica under Arsenic, Aluminium and salt stress. Plants were cultivated in the presence of increasing concentrations of Al and As alone (200, 500 and 800 µM), or mixed with NaCl (200 mM). The results revealed that both metals altered the growth and development of T.gallica . Finding showed that the metals’ accumulation was dependent on the concentrations of the metals in the medium. Interestingly, while salt reduced As uptake, an augmentation in Al accumulation was observed. In addition, T. gallica demonstrated that APX was the predominant enzyme to scavenge excess ROS. However, SOD and GPX were sensitive to the metal, showing different behaviour in metal stress alone or combined with salt. Proline accumulated in a dose-dependent manner under Al and As stress, rather than lower or unchanged levels of glycine betaine. We also noticed a diminution in proline content caused by NaCl application while an increase in glycine betaine was remarked. On the other hand, the combined stress enhanced proline whereas unchanged levels of glycine betaine were observed. Finally, T. gallica demonstrated its potential to grow under elevated concentrations of As/Al and could be considered a suitable candidate for phytostabilization/ phytoremediation approach.