| Kentucky bluegrass (Poa pratensis.L) has the characteristics of long-green periods, soft-qualities, brilliant-colors, strong cold-tolerance, great tiller density and so on.As Kentucky bluegrass is one of the temperate turfgrasses, it still has difficulty in overcoming summer stress in transitional areas including Nanjing. In this experiment,9Poa pratensis varieties were used for this study. The paper compared the dynamic changes of the turf characters et physiological and biochemical characteristics in field across summer in Nanjing, and the heat tolerance mechanism were also preliminary exploration.According to the results, coverage, tiller density, turf quality, leaf chlorophyll and water content declined markedly (p<0.05) with the swelling and persisting stress of heat and drought.Balance of antioxidant systems had been broken and cell membrane was destroyed in high temperature stress in summer. Study proves that the leaf membrane permeability and malondialdehyde (MDA) content increased significantly (p<0.05) with increasing temperature.Soluble protein content decreased significantly (p<0.05). Ascorbic acid (AsA) and reduced glutathione (GSH) were increased in the beginning of high temperature stress. But they were decreased with the temperature rised.The experimental results also shows that the declined degree of turf quality, leaf water content, SOD and POD activities, and the increased degree of membrane permeability and MDA et change range of ASA and GSH in summer high temperature stress significantly(p<0.05) differed among the varieties. Chages degree in Nudesting and Barrister was less than the other varieties such as in Park and Bluemoon. Turf quality of Nudesting and Barrister was higher than the other varieties. On the Basis of the turf character and the change value of each physiological charxteristic of incidence coefficient and order of the9Kentucky bluegrass varieties it can draw a ranking of heat resistance, as follows: Nudesting>Barrister>Total> Liberator>Award>Nuglade>America>Bluemoon>Park... |
