Abstract: 【Objective】The suitable air temperature is necessary for growth of grapes. Heat stress often happens in south area of China during grape mature period. The industrial economic benefits of grape are affected by the water-lost leaves and sunburn fruits. So study on the responsive mechanism of grapevines under high temperature stress is particularly important. The present research is mainly focused on the high temperature stress response of young grapes under control condition. As studies on response to high temperature stress in adult grapes are limited, so detailed explanation of high temperature damage in grapevines at different ages could provide a theoretical foundation for prevention of high temperature adversity. 【Method】 This study used 8 table grape varieties in south area of China as experimental materials, including Zuijinxiang, Summer Black, Kyoho, Jumeigui, Shenyu, Shenhua, Shenfeng, and Hupei 1#. Young grapevines (1-year-old) at the same growth stage were acclimated for 7 days in a controlled environment room, with a photoperiod of 14 h light under cool-white fluorescent light at 100 μmol·m-2·s-1. The grape plants were divided into 3 groups and were acclimated for 7 days at normal temperature (25℃). On the following day, 1 group of grapevines was kept at 25℃ in this controlled environment room. The other 2 groups were treated at 35℃or 45℃, respectively, from 10：00 h to 16：00 h (which was stimulated the high temperature levels in the day). The heat response was tested at 0, 3 h, 6 h and 150 h. In addition, the 6-year-old adult grapevines were selected to study heat stress response under field conditions in the present experiment, July 23, 2015 (denoted as “37℃”; highest temperature <40℃) stood for pre-temperature stress and July 31, 2015 (denoted as “42℃”, highest temperature >40℃) stood for post-temperature stress. 【Result】 The phenotype of young grapevines under high temperature stress was observed. The young sprout and aging leaves of Shenyu, Summer Black and Shenhua showed lightly water-loss at the beginning of high temperature stress, and recovered at 150 h. The leaves of Kyoho and Jumeigui showed slightly water-loss at 3 h and seriously water-loss at 6 h under high temperature stress. The leaves of Shenfeng, Hupei 1# and Zuijinxiang showed a seriously water-loss at 3 h, and the leaves of whole plant dry rot at 6 h under high temperature stress. And different temperature treatments (35℃/45℃/42℃) induced the expression of resistance genes in young and adult grapevines. However, the expression of genes in levels were different. The higher temperature level induced the greater gene expression. In addition, the expression of GLOS1 and HSFA2 in Shenyu, Shenhua, Zuijinxiang, Kyoho, and Jumeigui and the expression of HSP70 in Shenyu, Shenhua, Summer Black, and Kyoho recovered to the original levels at 6 h/150 h after high temperature treatments. The expression of HSP17.9 was increased by high temperature stress and the expression was not decreased with the prolongation of time. High temperature treatments (45℃/42℃) induced the expression levels of HSP21 protein in young and adult grapevines, however, the expression levels of HSP21 protein decreased in some varieties (Shenfeng and Zuijinxiang). 【Conclusion】 It was found that there are differences between different grape cultivars in the tolerance to high temperature stress. Firstly, Shenyu, Shenhua, and Summer Black are more tolerant to high temperature than others. Secondly, the system of heat-tolerance in Kyoho and Jumeigui collapsed. And then, Shenfeng, Hupei 1# and Zuijinxiang belong to the heat-sensitive grape cultivars. In addition, the differences of expression of genes and proteins between the grape seedling and adult trees were due to the tree age and the happening way of high temperature stress.

Key words: grapevine, high temperature stress, resistance genes, HSP21