Leaf Physiological and Water Soluble Carbohydrate Content Responses to Trinexapac-ethyl Application of Sports Turf Grasses Exposed to Water Stress

Water stress causes alterations in physiological and metabolic processes in plants and is considered the primary environmental factor affecting the management of sports turf grass species.This glasshouse experiment was conducted to investigate the effect of trinexapac-ethyl (TE) on canopy net photosynthesis (Pn), cell membrane stability (CMS), turf quality (TQ) and water soluble carbohydrate (WSC) accumulation responses of sports turf cultivars [Cv] (100% fescue, Rootzone and Arena sports) subjected to water stress. Commercially obtained sods of turf plants were treated with 2 L/ ha TE and then exposed 7 days after to water stress. The treatments were: (i) water untreated, (ii) water TE-treated, (iii) water stress untreated; and (iv) water stress TE-treated and the experiment was a randomized complete block design with four replicates. Results showed that specifically in Cv. Rootzone, Pn was 50% higher for well water TE treated plants compared to the other treatments during the second and third week of the study. Similarly, at 14 days after application, the effect TE resulted to 35% and 50% reduction in cell membrane leakages respectively in well water and water stressed TE-treated Cv. Rootzone plants and this was statistically significant (P=0.05) different from the untreated plants. On a scale of 1-9, all turf types recorded TQ rating of ≥8 at the start of the experiment. By the fourth week of the study, it was observed that all water stress untreated plants had mean TQ (5.75) ratings lower than the minimum acceptable TQ (6). WSC content of well-watered TE-untreated plants was maintained below 60 mg/g DW throughout the study regardless of turf type. After 28 day of water stress duration, the WSC contents obtained in water stress TE-treated plants were 41%, 43% and 50% higher for Cv. Rootzone, 100% fescue and Cv. Arena sports, respectively , than in well water untreated plants. Summer preconditioning of plants with TE can be a possible management tool in alleviating the detrimental impacts of water stress in sport turf species.