Differential Growth And Physiological Responses To Heat And Drought Stress Between Two Ecotypic Creeping Bentgrasses

Originated from Eurasian continent, Agrosits stolonifera L. is among the most popular Poaceae cultivars for urban greening and out-door stadium. However, this type of cool-season turfgrass suffers from the summer heat and misdistribution of rain drops of southern China. The ability of turf grasse to survive unwilling conditions verifies from cultivars and its physiological features. Still, numbers of evaluation remain to be done on resistance to stresses among cultivars, especially during the condition of combined stress. The following research is a comprehensive evalution of two bentgrass cultivars under drought, heat and combined stresses. Turf quality, membranes stability, antioxidant system, photosynthetic activity and roots development are vital indexes in this study.1. This part of the experiment was designed to investigate drought, heat and combined stresses on Agrostis stolonifera ’L-93’ and ’XJ-1’ by analyzing relative water content, electrolyte leakage and enzymes for anti-oxidant. Transient increase in superoxide dismutase (SOD) and decreases in catalase (CAT), peroxidase (POD) and ascrobate peroxidase (APX) occurred in drought, heat and combined stress. Different results between two cultivars was observed under different treatmens. Relative water content, electrolyte leakage and Malondialdehyde (MDA) indicated less damage for ’XJ-1’ than ’L-93’.2. In addition to previous study, leaves and roots are taken from both ’L-93’ and ’XJ-1’ for analyzing. During 24 days simulated drought condition, turf quality, osmotic pressure, photosynthetic activity and roots indexes are evaluated for both cultivars. As a result of dehydration, turf quality, electrolyte leakage, photochemical efficiency, photosynthetic indexes and roots length were significantly influenced. Relative water content, electrolyte leakage and Malondialdehyde (MDA) indicated less damage for ’XJ-1’ than ’L-93’.In control group, indexes indicate a better Pn and OP level of ’XJ-1’. Under drought treatment, better OP regulation was read for ’L-93’.Higher anti-oxidant enzyme and tissue water level, combined with developed roots system and stronger photosynthesis brings the ability to ’XJ-1’ to resist unwilling living conditions better than ’L-93’.’XJ-1’ remains to be the potential candidate as a future breeding material.