The effect of drought preconditioning on increasing drought stress tolerance in two turfgrass creeping bentgrass (Agrostis stolonifera cv. Palustris) and tall fescue (Festuca arundinacea cv. Greystone)

Drought preconditioning (DP) is a method of irrigation with low frequency and longer duration, to extend the root system and suppress drought damage in plants. In the present study, the effect of DP for 30 days on increasing tolerance to drought stress in two turfgrass species, creeping bentgrass (Agrostis stolonifera cv.Palustris) and tall fescue (Festuca arundinacea cv. Greystone) was investigated. DP and control plants were irrigated for 50 days with different levels of soil suction (20-23,40-43, 50-53 and 70-73 centibar), and finally, plants were watered up to field capacity point for 15 days, to recover from stress. Results showed that DP significantly lead to reduction in shoot length and increase in root length in both turfgrass species. DP plants showed less shoot dry and fresh weight and also less electrolyte leakage (EL) at each levels of stress, in compare with the control. Furthermore, DP plants showed greater reduction in EL after recovery. DP treatment also reduced leaf RWC at the end of 50 days of stress and after recovery in tall fescue, but in creeping bentgrass retained it at the control level. Overall, it appears that DP treatment can increase tolerance to drought stress in two species with increasing root length, reducing shoot length and EL and preserving leaf RWC.