Effects of three exogenous substances on the physiological indexes of tall fescue under salt stress

To determine the adaptability to salt stress, tall fescue (Festuca arundinace) was taking as the material to examine the effects of three exogenous compounds such as potassium sulfate (K₂SO₄), glycine betaine (GB), and ascorbic acid (AsA) on salinity resistance. Turf quality (TQ), relative water content (RWC), osmotic adjustment, electrolyte leakage (EL), malonaldehyde content (MDA), ion content, and antioxidant enzymes were measured in tall fescue under non-stresssed and salt stressed conditions. The results showed that spraying K₂SO₄, GB, and AsA could improve salt resistance of tall fescue to some extent. Overall, spraying GB had the best performance, followed by AsA. Compared with other treatments, spraying GB improved the quality of tall fescue under salt stress more effectively and inhibited the decrease of relative water content of leaves; however, leaves had higher osmotic potential and lower electrolyte leakage rate. In addition, GB treatment had a significant effect in inhibiting the accumulation of malondialdehyde and H₂O₂, and delaying the decrease of catalase and ascorbate peroxidase enzyme activities. Overall, this study confirms that exogenous GB treatment can improve the osmotic regulation ability and activity of antioxidant enzyme on tall fescue, consequently improving the resistance of salt tolerance.