Chemical priming and plant growth regulator effects on drought resistance characteristics of creeping bentgrass

Despite widespread use of plant growth regulators (PGRs) their interaction with other plant treatments associated with stress tolerance is poorly understood. Greenhouse and growth chamber studies were conducted to determine the effects of seven chemical priming compounds on drought responses under growth chamber and field conditions on creeping bentgrass ‘T1’ (Agrostis stolonifera). The treatments were: control, trinexapac-ethyl (TE), salicylic acid (SA), gamma amino butyric acid (GABA), jasmonic acid (JA), TE + SA, TE + GABA, and TE + JA. Leaf relative water content (RWC), soil volumetric water content (SWC), leaf electrolyte leakage (EL), turf quality (TQ), normalized difference vegetation index (NDVI), canopy temperature depression (CTD) and leaf chlorophyll content were measured in plants under well-watered and drought-stressed conditions. Under drought stress in the growth chamber, TE+SA and TE treated plants had a significantly higher TQ and lower EL than the controls. TE+SA, TE, TE+JA, and TE+GABA treated plants had a higher RWC and a lower CTD than the control. In field conditions, plants treated with TE+SA, TE, and TE+JA had a higher SWC, TQ, NDVI, and RWC than the controls. The results from this study suggest that out of the various chemical priming agent treatments tested, TE and TE plus priming agents (TE+SA, TE+JA, and TE+GABA) were most effective in alleviating drought stress of creeping bentgrass through avoidance and tolerance. Treatment with TE alone had the same effect as TE supplemented with SA, GABA or JA.