Physiological Responses Of Drought Stress And Post-drought Re-watering In Two Interspecific Kinds Of Turfgrasses

Drought stress is one of the most important abiotic stresses limiting plant growth in many arid areas.The damage is characterized by leaf dehydration and senescence during mild and moderate stress and desiccation under severe conditions.Therefore,to understand the mechanism of drought tolerance and post-drought recuperative ability is very important for breeding drought tolerant cultivars.For perennial plant species,rapid rehydration and recovery of damaged plant tissues are most effective drought survival strategies when water becomes available,but few studies examined physiological and morphological traits associated with differential recuperative ability between warm-season and cool-season turfgrass species in response to re-watering.Four common turfgrasses detached leaves were screened under drought stress as a pre-experiment,which were Manilagrass 'NJ-1',Seashore Paspalum '2000',Kentucky bluegrass 'Excursion II' and Tall fescue 'Barlexas'.According to the detached leaves relative water leakage(RWL),finally selected the best Manilagrass and the worst Kentucky bluegrass as the tested materials.The following research is a comprehensive evaluation of Manilagrass and Kentucky bluegrass under drought stress and post-drought re-watering.The main contents and results as following:This part of the experiment was designed to investigate drought stress and post-drought re-watering on Manilagrass and Kentucky bluegrass by analyzing relative water content(RWC),leaf rolling rate(LRR),specific leaf area(SLA),electrolyte leakage(EL),Malondialdehyde(MDA),osmotic adjustment(OA),leaf wax content(LWC),water use efficiency(WUE),leaf chlorophyll content(Chl)and photosynthetic indexes(gs,Tr,Pn,Ci).Results showed that,compared to Kentucky bluegrass,Manilagrass maintained higher TQ,RWC,SLA,LRR and Ch1,and membrane stability expressed as EL during drought stress.Manilagrass also had better OA and LWC,maintained the osmotic balance and higher WUE,provided a relative stable environment for the physiological reaction.Another part of the experiment was designed to investigate drought stress and post-drought re-watering on Manilagrass and Kentucky bluegrass by analyzing root cap ratio(R/S),biomass of root and shoot,root length and area in 0-20 and 20-50cm soil layer.Results showed that,compared to Kentucky bluegrass,Manilagrass maintained higher R/S,biomass,root length and area in different soil layer.Higher tissue water level,better osmotic adjustment,combined with developed roots system and strong photosynthesis brings the ability to Manilagrass to resist unwilling living conditions better than Kentucky bluegrass.