Physiological Factors Associated with Drought Tolerance and Recuperative Ability in Kentucky Bluegrass and Perennial Ryegrass.

Understanding physiological factors underlying drought tolerance and recovery is important for developing turfgrass species used in water limiting environments. The objectives of this study were to examine inter-specific variation in physiological changes in response to drought stress and re-watering. The experiment was conducted in a greenhouse with plants growing in plastic tubes (60 cm in depth and 10 cm in diameter) filled with soil. Plants of Kentucky bluegrass (KBG) (cv. ‘Midnight’) and perennial ryegrass (PR) (cv. ‘Paragon GLR’) were maintained well watered as control or exposed to drought stress by withholding irrigation (drought), and then re-watered to allow for full recovery (re-watering). Leaves of KBG were able to maintain significantly higher relative water content, but lower electrolyte leakage than PR leaves when irrigation was withhold for 21 d. In addition, in a test with detached leaves exposed to dehydration, KBG leaves loss water significant slower than PR leaves. Upon re-watering, drought-damaged leaves of KBG were rehydrated to full turgor within 2 days while PR turf could not fully recover from drought damage until new leaves were regenerated. Our results indicated that leaf dessication tolerance and rehydration in cool-season turfgrass plants was positively associated with cell wall extensibility and cell membrane stability.