Physiological response of diverse halophytes to high salinity through ionic accumulation and ROS scavenging.

Salt stress induced modulations in different ionic ratios and ROS system were studied in ten halophytic species, namely at salinity level of ECe ∼ 30 dSm (≈300 mM NaCl) to explore their possible role in salt tolerance ability of these halophytes. These halophytes were categorized for their salt tolerance levels based on the ratios of Na/K, Na/Ca, Na/Cl and Na + Cl/K + Ca. Variable responses were observed among all halophytes where had lowest leaf Na/K (0.44) which is one of the best indicator of salt tolerance, had lowest Na/Ca and Na/Cl (0.97 and 0.18), whereas had lowest Na + Cl/K + Ca (0.79). Specific enzymes activities of ascorbate peroxidase (APX), superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX) were also assessed to get better comprehension of the ROS scavenging system under salinity in these halophytes. showed highest APX and SOD activity followed by . Most efficient enzyme in degrading hydrogen peroxide i.e. CAT showed highest activity in followed by and , whereas and showed higher POX activity. Significant variability in HO and MDA content was also observed. These results possibly suggest higher inbuilt genetic potential of these halophytes to combat high salinity induced oxidative stress via higher antioxidant activities. : Halophytic plant adopt different strategies to cope up with the toxic ions and our studies show that the induction of antioxidant defense system to scavenge ROS, alongwith structural modifications in terms of lipid peroxidation and compartmentalization of toxic ions are the main strategies for tighter control of ion fluxes in the studied halophytes.