Polyamine Content Regulation Associated with Salt Stress of Creeping Bentgrass.

Creeping bentgrass (Agrostis stolonifera) is a turfgrass species that is sensitive to salinity stress.  Polyamines [PA; putrescine (Put), spermindine (Spd), and spermine (Spm)] play roles in plant growth development and abiotic stress responses but little is known about their role in turfgrass species. Therefore, this growth chamber study was designed to evaluate physiological responses to salt stress in two creeping bentgrass cultivars differing in salt tolerance (‘Penncross’ and ‘Psg1sltz’). Plants were exposed to salt in a stepwise fashion up to 24 dS/m. Turf quality and relative water content dropped significantly after 16 dS/m of salt exposure. Leaf osmotic pressure significantly decreased as salinity increased with significant lower value of ‘Penncross’ than ‘Psg1sltz’. PA content analysis indicated that Spd is the major PA compound in creeping bentgrass while Put and Spm were present in significantly lower amounts. At 16 and 24 dS/m of salt concentration, Spd concentration was significantly lower than the controls (no salt treatment).  At 24 dS/m, the concentration of Put in salt treated plants was significantly higher than in control plants. This study is currently being repeated to confirm the results of PA regulation due to salt stress.