Responses to elevated carbon dioxide for postdrought recovery of turfgrass species differing in growth characteristics

Elevated CO2 concentration affects plant responses to drought, but its effects on poststress recovery for perennial grass species with different growth habits are unclear. The objective was to determine how stoloniferous and bunch-type grass species may exhibit differential responses to elevated CO2 concentration during drought stress and postdrought recovery upon rewatering due to different growth characteristics. Stoloniferous creeping bentgrass (Agrostis stolonifera L.) 'Penncross' and bunch-type tall fescue [Schedonorus arundinaceus (Schreb.) Dumort] 'Sitka' were grown at ambient CO2 (400 mu l L-1) or elevated CO2 concentration (800 mu l L-1) repeated in four growth chambers for 28 d, subsequently subjected to either irrigation (control) or drought stress (irrigation completely withheld) for 28 d, and then rewatered for 18 d. During drought stress, both species exposed to elevated CO2 maintained higher turf quality, leaf water content, and membrane stability than plants at ambient CO2. Elevated CO2 caused significant increases in the viability of stolon-node meristematic tissues in creeping bentgrass under drought stress and rapid regeneration of daughter plants during rewatering, as shown by increased shoot biomass and percent turfgrass cover. Elevated CO2 had no significant effects on the viability of crowns with meristematic tissues in tall fescue during drought nor shoot biomass or percent turfgrass cover during rewatering. The stoloniferous grass species was more responsive to elevated CO2 compared to bunch-type species for poststress recovery, as creeping bentgrass rapidly regrew and recovered from drought damages. Such information is of great importance for making appropriate turfgrass selections and breeding improvements in growth habits in areas with prolonged drought and the anticipated rising CO2 levels.