The Effect Of Mowing On Growth And Physiological Characteristics Of Tall Fescue Under Heat Stress

Tall fescue (Festuca arundinacea. Schreb) is widely used in turf industry in the region of middle and lower reaches of the Yangtse River. Tall fescue has the characteristics of heat-tolerance, longer green period, low requirement to water and fertilizer and extensive management. Tall fescue is one of the temperate turfgrasses, when high temperature and drought environment occurred during July and August, its growth was inhibited and even it can not survive well in this period. Two tall fescue breeds with different heat-tolerance capability were used in the experiments, which are Cochise and Barlexas. Growth characteristics and changes in antioxidant system of leaves and roots of tall fescue were studied with three mowing height (3.8cm, 5.6cm and 7.8cm) treatments, and also canopy photosynthetic rate of tall fescue was study under high temperature and summer drought.As the results, the contents of leaf water and chlorophyll, growth rate of tall fescue decreased significantly (p<0.05) with increasing temperature in August. Turf quality with high and moderate mowing height was better than that with low mowing height during August and September. Leaf chlorophyll with high and moderate mowing height showed higher content as compared with low mowing height, their reduction extent was lower than that in May. This indicated that growth rate and leaf water content decreased slowly with high and moderate mowing height in high temperature stress.Balance of antioxidant systems had been broken and cell membrane was destroyed in high temperature stress in summer. The results showed that electrolytic leakage and malondialdehyde content increased significantly (p<0.05) with increasing temperature, Soluble protein content decreased significantly (p<0.05). The activities of superoxide dismutase(SOD), peroxidase(POD) and catalase(CAT) of leaf increased sharply(p<0.05) and then decreased significantly (p<0.05). At the beginning of high temperature, the activity of leaf POD and root CAT and soluble protein were kept on higher level, EL and MDA content showed lower with high and moderate mowing height. Under continuous high temperature, the activities of SOD, POD and CAT and solute protein of leaves and...