Physiological and Antioxidative Responses of a Halophytic Grass Leptochloa fusca L. Kunth (Kallar grass) to Salinity

The effects of salt stress on growth and some physiological parameters of halophytic plant, Leptochloa fusca L. Kunth, were investigated. The seedlings were irrigated with half-strength Hoagland solution and then treated with different concentrations of NaCl (0, 100, 300, 500 and 700 mM) for 15 days. The fresh and dry weights of both root and shoot were unchanged at 100 mM NaCl and decreased at higher concentrations. Relative water content significantly decreased at high NaCl treatments. The significant increase in the contents of chlorophylls and carotenoids due to NaCl stress was observed in all salinity treatment except for100 mM NaCl. Leaf Na+/ K+ ratio increased with increase in medium salinity. Moderate (300 mM) and high (700 mM) salinities dramatically increased proline content as compared to that of control group. With a progressive increase in salinity, catalase, ascorbat peroxidase and guaiacol peroxidase activities also increased gradually in this species. It seems that antioxidant enzyme activity for scavenging reactive oxygen species and proline accumulation for osmotic adjustment play an essential protective role in L. fusca under salinity stress. In summary, these data indicate that salinity tolerance is well programmed in L. fusca allowing adaptation to harsh environmental conditions in the natural habitat.