Changes In Antioxidant Enzyme Activity In Turfgrass Cultivars Under Various Saline Water Irrigation Levels To Suit Landscapes Under Arid Regions

摘要

Turfgrass cover is an inevitable component in the urban landscapes of the United Arab Emirates. Tolerance to abiotic stress like salt, drought, and high temperature is a potential factor to be considered in the selection of turfgrass for the landscapes in the arid regions. Three Seashore paspalum genotypes, four Bermudagrass cultivars along with tall fescue as a control were screened for enzymatic changes under four different saline irrigation levels of 5,000, 10,000, 15,000, and 20,000mg L-1 of salinity. Irrigation with potable water served as the control. Turfgrasses were maintained in a field experiment under factorial randomized block design for a period of two years under sustained saline conditions by working out the leaching fraction to maintain the precise level of salinity in each treatment throughout the experimental period. The activities of antioxidant enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APX), peroxidase (POD), polyphenol oxidase (PPO), and catalase (CAT) were assayed in each of the saline water treated turfgrass types. The SOD activity was found to be high in Yukon (bermudagrass) and Sea Dwarf paspalum. In the paspalum group, Salam and Sea Dwarf showed the highest SOD activity under saline condition. In Bermuda types, Yukon and SR 9554 showed the highest SOD activity compared to other bermuda types. Compared to other cultivars, Sea Isle 2000 (Paspalum type), SR 9554, and Yukon (Bermuda types) exhibited more APX activity without any significant differences among themselves. There was an elevated activity of POD initially, followed by gradual reduction upon increasing the salinity level. Salam cultivar maintained stable POD activity even at the elevated salinity levels. The paspalum types showed relatively high level of PPO activity compared to other types under salinity. Yukon cultivar showed a significantly higher activity of PPO when the salinity level was raised from 15,000 to 20,000mg L-1. A significant increase with respect to CAT activity was exhibited in Sea Dwarf under elevated level of salinity. Saline water irrigation brought about a significant effect on the antioxidant enzyme systems to impart oxidative stress tolerance in turfgrass species.