H₂O₂ Pretreatment Modulates Growth and the Antioxidant Defense System of Drought-stressed Zoysiagrass and Kentucky Bluegrass

This study investigated the effect of exogenous hydrogen peroxide (H₂O₂) on the antioxidant responses and growth of warm-season turfgrass (Zoysia japonica Steud.) and cool-season turfgrass (Poa pratensis L.) subjected to drought stress. Compared with control plants that were not pretreated with H₂O₂, plants pretreated with H₂O₂ had significantly greater fresh and dry weights of shoots and roots, and increased water content. H₂O₂ pretreatments before drought stress significantly decreased the concentrations of malondialdehyde and H₂O₂. DPPH radical scavenging and glutathione activities were significantly increased. The responsive activities of the antioxidant enzymes superoxide dismutase, ascorbate peroxidase, catalase, and peroxidase were also significantly enhanced. Our results suggest that exogenous H₂O₂ could improve the growth of warm-season and cool-season turfgrass under drought stress by increasing the activity of their antioxidant enzymes, while decreasing lipid peroxidation.