Comparative Effects of Drought and Salinity Stress on Creeping Bentgrass and the role of Glycine Betain as a Stress Reducing Compound.

Limited availability of potable water has resulted in the movement to use recycled, non-potable water sources for irrigation of turfgrasses resulting in higher occurrences of salinity and osmotic stresses. The objective of this study is 1) to compare growth and physiological effects between drought and salinity for creeping bentgrass; 2) to determine whether plants differentiate in stress mechanisms for drought and salinity; and 3) to quantify the effects of the compound glycine betain (GB) for improvement of stress tolerance. Cultivars being examined are ‘Penncross’ and ‘Penn A4’ creeping bentgrass (Agrostis palustris Huds.). Treatments of salt (NaCl) and drought using polyethylene-glycol 6000 (PEG) were adjusted to an osmotic potential of -0.66 MPa and glycine betain was applied at a rate of 8 kg/ha by foliar application. Visual turf quality has decreased in the PEG treated plants more extensively than in the NaCl treated plants. Drought plants display a consistent reduction in quality with no identifiable improvements due to GB. Leaf photochemical efficiency (Fv/fm) has indicated higher levels of chlorophyll fluorescence in NaCl treated plants than their respective controls.  Drought plants display a consistent reduction in quality with no identifiable improvements due to GB.