Effects of High Temperature Stress on Some Physiological Indexes in Seedling of Kentucky Bluegrass

In order to explore the physiological mechanism of high temperature injury to cool-season turfgrass,the effects of high temperature(42.0 0.5) ℃on some physiological indexes in seedling of Total Eclipse(Poa pratensts L.)were studied.The results showed that electrolyte leakage and malondialdehyde(MDA) contents in seedling were higher significantly under high temperature stress than those in the control group during high temperature stress.In the meanwhile the activities of superoxide dismutase(SOD),contents of soluble protein and glutathione(GSH)were lower significantly under the high temperature stress than those in the control group during high temperature stress.The contents of soluble sugar,proline and ascorbic acid(AsA)were increased slightly at 2 d under the high temperature stress,but the contents were lower significantly afterwards than those in the control group.Therefore,it is proposed that the significant increase of the electrolyte leakage and MDA contents and significant decrease of the SOD activities and the contents of soluble protein,GSH,soluble sugar,proline and AsA were physiological mechanism of high temperature injury to cool-season turfgrass.