Superoxide Dismutase Activity In Leaves and Stolons of Two Warm-Season Turfgrass Species In An Arid Environment.

Drought, salinity and heat are typical environmental stresses for arid and semi-arid areas. Reactive Oxygen Species may be formed in plants subjected to such stresses. The first defense mechanism of plants against these species is the Superoxide Dismutase (SOD) enzyme that catalyzes the transformation of superoxide radical into hydrogen peroxide. A study was conducted at New Mexico State University in Las Cruces, NM during the summers of 2010 and 2011 to determine turf quality and SOD activity of bermudagrass [Cynodon dactylon (L.)] cultivar Princess 77 and seashore paspalum [Paspalum vaginatum (Swartz)] cv. Sea Spray treated with either a soil surfactant (Revolution) or a PGR (Primo MAXX) at label rate. Irrigation was applied daily at 50% ET₀ from either a sprinkler or a subsurface-drip system with either saline (TDS = 1600 ppm) or potable (500 ppm) water. Leaves and stolons were sampled monthly from July until September. Turf quality and SOD activity in leaves and stolons were higher in plots treated with Primo Maxx compared to an untreated control. Generally, SOD activity was higher during the summer of 2011 than 2010 as a result of higher air temperatures and lower rainfall amounts. Although no differences in turf quality were found between the two species, enzyme activity recorded in bermudagrass was higher than that recorded in seashore paspalum suggesting that other defence mechanisms to oxidative stress are present in seashore paspalum. Saline irrigation water and type of irrigation did not affect SOD activity. Although plots with highest turf quality also had highest SOD activity, no significant correlation between enzyme activity and visual ratings was found.