Authors : Faycal Boughalleb, Mahmoud Mhamdi, Hichem Hajlaoui and Mounir Denden
Abstract: The effect of NaCl stress on the growth, organic compounds content and antioxidant enzymes activities were investigated in two xero-halophytes Nitraria retusa and Atriplex halimus. Plants were grown in 0-800 mM NaCl for 120 days under glasshouse conditions. Both xero-halophytic species showed positive plant growth for low levels of salinity. Increasing concentrations of salinity from 400-800 mM, NaCl induced decrease in plant growth in the two species, especially in A. halimus. In addition, both species were able to accumulate a large quantity of Na+ and to maintain a higher leaf water content which was probably associated with a greater capacity for osmotic adjustment whereas the contents of K+ decreased significantly, resulting in an increase in the Na+/K+ ratio when NaCl concentrations increased. Organic osmotica was highly involved in osmotic adjustment in A. halimus leaves, especially glycinebetaine. In N. retusa leaves, glycinebetaine, soluble sugar and proline were increased by salinity. The relatively better salt tolerance of N. retusa compared to A. halimus plants may be related to the lower Malondialdehyde (MDA) content and hydrogen peroxide (H2O2) concentration and the increased activity of Catalase (CAT) and Peroxydase (POD) which participate to protect cells from ROS damage. In A. halimus, the higher antioxidant enzyme activities (Superoxide Dismutase, SOD; Catalase, CAT; Peroxydase, POD) play a major role in the restriction of oxidative damages caused by salt stress.
Faycal Boughalleb, Mahmoud Mhamdi, Hichem Hajlaoui and Mounir Denden, 2010. Salinity Effects on Organic Solutes and Antioxidative Enzymes in Two Halophytes, Nitraria retusa (Forssk.) and Atriplex halimus (L.). Research Journal of Biological Sciences, 5: 773-784.