Growth Responses of Selected Warm-Season Turfgrasses under Salt Stress

Abstract

Use of low quality/saline water for turf irrigation, especially in regions experiencing water shortage is increasing. This imposes more salt stress on turfgrasses which are already under stress in these regions. Therefore, there is a great need for salt tolerant turfgrasses to survive under such stressful conditions. This study was conducted in a greenhouse, using hydroponics system, to compare growth responses of three warm-season turfgrasses, bermudagrass (Cynodon dactylon L.), cv. Tifway 419, seashore paspalum (Paspalum vaginatum Swartz), cv. Sea Isle 2000, and saltgrass (Distichlis spicata L), accession A55 in terms of shoot and root lengths and DM, and canopy green color (CGC) under salt stress condition. Whole plants, stolons, and rhizomes were grown in Hoagland solution for 4 months prior to initiation of salt stress. Then, plants were grown for 12 weeks under 4 treatments (control, 7000, 14000, and 21000 mg/L NaCl) with 4 replications in a RCB design trial. During the stress period, shoots were clipped bi-weekly for DM production, shoot and root lengths were measured, and CGC was evaluated weekly. The bi-weekly clippings and the roots at the last harvest were oven dried at 60o C and DM weights were recorded. Shoot and root lengths and shoot DM weights decreased linearly with increased salinity for bermudagrass and paspalum. However, for saltgrass these values increased at all NaCl levels compared with the control. For bermudagrass and paspalum, the highest values were obtained when the whole plants were used, and the lowest ones resulted when the rhizomes were used. The reverse was found for saltgrass. For the control plants, the measured factors were higher and the canopy colors were greener for bermudagrass and paspalum compared with saltgrass. The canopy color changed to lighter green for bermudagrass and paspalum as NaCl salinity increased, but saltgrass maintained the same color regardless of the level of salinity.