Effect of high temperature stress on physiological indexes of six lines of tall fescue

A experiment was conducted to monitor the effect of high temperature stress on physiological indexes of the original lines and six lines and five better offsping from irradiated mutants of tall fescue in the artificial climate chamber for comparing the heat tolerance of six lines and providing the reliable theory basis for selecting coolseason turfgrasses with strong heat tolerance. This study showed that the injury rate of all lines, the MDA and proline content increased, and that the activity of superoxide dismutase (SOD), chlorophyll and soluble protein content firstly increased, and then decreased, and that the soluble sugar content decreased as the high temperature stress time continued. Based on subordinate function analysis, a comprehensive evaluation indicated that the order of heat resistance of six lines followed the pattern with HN001HN005 HN002HN006HN003HN004．