Growth and Enzymatic Activity of Four Warm-season Turfgrass Species Exposed to Waterlogging

Waterlogging (WL) negatively affects plant growth and development, but the physiological responses of turfgrass species to WL are not well understood. The objective of this study was to examine growth and physiological mechanisms of WL tolerance in warm-season turfgrass species. Knotgrass (Paspalum paspaloides), spiny mudgrass (Pseudoraphis spinescens), seashore paspalum (Paspalum vaginatum), and centipedegrass (Eremochloa ophiuroides) were subjected to 30 days of WL. At the end of the treatment, knotgrass and spiny mudgrass maintained the shoot and root biomass while seashore paspalum and centipedegrass showed reductions in biomass under WL. Root oxidase activity (ROA) was unaffected until after 12 or 18 days of WL but decreased by 14.3%, 17.8%, 32.0%, and 68.7% at 30 days of WL for knotgrass, spiny mudgrass, seashore paspalum, and centipedegrass, respectively. Waterlogging increased root activities of lactate dehydrogenase and alcohol dehydrogenase, but generally to a lesser extent in knotgrass and spiny mudgrass. The leaf and root activities of superoxide dismutase (SOD) and peroxidase (POD) were induced after 6 or 12 days of WL, but to a greater extent for knotgrass and spiny mudgrass. At 30 days of WL, the increased leaf and root activities of SOD and POD were higher in knotgrass and spiny mudgrass than that of seashore paspalum and centipedegrass; while centipedegrass showed 37.8% reduction in root SOD activity. The total soluble protein (TSP) concentration remained unchanged in both leaves and roots during the entire WL treatment for knotgrass, while a decreased leaf TSP was found in the other three species after 12 or 24 days of WL as well as in the roots of seashore paspalum and centipedegrass. More reductions in leaf or root TSP were observed in seashore paspalum and centipedegrass than in knotgrass and spiny mudgrass at 30 days of WL. The results indicated that higher ROA, activities of antioxidant enzymes and TSP contributed to WL tolerance of warm-season turfgrass species.