Exogenous nitric oxide alleviates oxidative damage in turfgrasses under drought stress

AbstractOxidative stress caused by drought stress is a major limiting factor for grass cultivation in arid and semi-arid regions. In order to investigate the effect of nitric oxide (NO) donors on drought tolerance and recovery of Poa pratensis L. ‘Balin’, Lolium perenne L. ‘Numan’ and Cynodon dactylon [L.] Pers., sodium nitroprusside (SNP) and potassium nitrite (PN) were applied at 150, 200 and 250μM concentrations with irrigation intervals of 3, 5, 7 and 9days. The NO donors significantly increased the antioxidant enzymes' activity of the three grass species during drought stress. This enhancing effect was not dependent on the source of NO (SNP or NP), but rather reliant on their concentrations. The maximum activity of catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) and ascorbate peroxidase (APX) was obtained with the application of 200μM SNP or PN. Nitric oxide donors caused the greatest increase in activities of antioxidant enzymes in plants subjected to 7 or 9days of drought stress. Among different turfgrasses tested under water stress, warm season turfgrass C. dactylon had the highest activity for antioxidant enzymes