Abstract: The influence of the high temperature stress on some physiological characteristics of flag leaves of the rice variety Yangdao 6 during the heading stage was studied.The results showed that the loss of the chlorophyll in the flag leaves was accelerated under high temperature stress,while the activity of superoxide dismutase(SOD),and the content of the ascorbic acid(ASA),the glutathione(GSH),the proline(Pro),the soluble protein and the soluble sugar significantly reduced by high temperature stress as well.Whereas the content of the electrolyte leakage and the malondialdehyde(MDA) significantly increased.The high temperature stress accelerated the senescence of leaf and caused the changes of other inner source substances,and then could reduce photosynthesis capability of the crop.

Key words: High temperature stress, High temperature stress, Rice variety Yangdao 6, Flag leaf, Physiological characteristics