The 2012 ASHS Annual Conference

Exogenous application of glycinebetaine (GB), an osmoprotectant increases tolerance to stresses including salinity in various plants, information on turfgrass, however, is limited. In this study, GB, was used to prime turf seeds for enhancement of salinity tolerance during the seed germination and seedling stage when plants are more sensitive to stresses. Seeds of perennial ryegrass (PR, moderately salt tolerant), tall fescue (TF, moderately salt tolerant), creeping bentgrass (CB, moderately salt sensitive), and Kentucky bluegrass (KB, salt sensitive) were unprimed or primed with 50, 100, 150, or 200 mM solution of GB or distilled water (DW) and then germinated in the solution of DW, mannitol (causing osmotic stress only), or NaCl ( causing both osmotic and ionic stresses) (their osmotic potential and salinity level were and –0.1 MPa and 0.1 dS·m^-1, –1.0 MPa and 0.1 dS·m^-1, and –1.0 MPa and 14.6 dS·m^-1, respectively). Seed germination and seedling growth in mannitol or NaCl solution were improved after seeds were primed with GB. Different turf species showed different responses to osmotic stress and ionic stress. No difference in germination and seedling growth of PR, TF, and KB was observed between mannitol and NaCl treatments, indicating that osmotic stress appeared to more critical than ionic stress. For CB, the seed germination rate and seedling growth were lower in NaCl than in mannitol, showing an accumulative effect of both osmotic and ionic stresses.