Changes in Creeping Bentgrass Salinity Tolerance after Seed Priming with Polyamines.

Salinity stress is one of the serious abiotic stresses threatening creeping bentgrass performance on golf courses where its location is near the shoreline or irrigated with recycled water containing high salt content. Polyamines (PA) are known to be stress protective to plants but their effects have not been widely evaluated on creeping bentgrass. Therefore, three types of PA (putrescine, Put; spermidine, Spd; spermine, Spm) were evaluated for efficacy as a seed priming agent against salt stress.  Three cultivar seeds of ‘Penncross’, ‘Declaration’, and ‘Marinar’ were soaked in Put, Spd, Spm, or water overnight before sowing. Three weeks after germination, all plants were exposed to 20 dS·m^-1 of salt solution for 45 days. Plant height, turf quality (TQ), electrolyte leakage (EL), relative water content (RWC), chlorophyll content (Chl), and final biomass were evaluated to indicate salinity tolerance. With Spm priming, ‘Penncross’, ‘Declaration’ showed less salinity damage based on EL, RWC, and Chl and less biomass production compared to water treated plants. After Put priming, plants showed more salinity damage with higher biomass production compared with the control. For ‘Marinar’, no differences were detected among treatments and their performance was better than ‘Penncross’ and ‘Declaration’.  In summary, seed priming with PA on creeping bentgrass seeds had significant effect on ameliorating salinity stress on ‘Penncross’ and ‘Declaration’ while non dramatic effect was seen in  ‘Marinar’.   Spm is the most effective compound on alleviating salinity stress on creeping bentgrass and such effect is derived from balancing between growth and ion toxicity.