高温对茶树叶片光合及抗逆特性的影响和恢复

以4个茶树品种福鼎大白茶、鸠坑、龙井43和乌牛早7a生植株为研究对象，采用人工气候箱模拟高温（35℃和40℃）处理6、12、18、24、48h，取出后置于人工气候箱中（25℃）恢复3、6、9d，以未经高温处理置于人工气候箱中（温度25℃）的各品种茶树为对照（CK），测定茶树叶片的最大净光合速率、荧光参数、抗氧化酶活性以及细胞伤害率。结果表明：高温胁迫显著抑制了茶树的最大净光合速率（Pnmax）和最大光化学效率（Fv/Fm），处理时间越长、温度越高，Pnmax和Fv/Fm下降越快，除35℃处理的福鼎大白茶外，其它3种茶树经过高温处理后，在恢复期间其Fv/Fm无法恢复至正常水平；茶树叶片的SOD酶活性在高温处理的前12h迅速上升，随着处理时间的延长，其活性降低；叶片MDA含量的平均值在高温处理第48小时达到最大，恢复期间缓慢下降；随着处理温度的升高和处理时间的延长，各茶树叶片的细胞伤害率均呈增加趋势。4种茶树耐热性的强弱由高到低依次为福鼎大白茶＞乌牛早＞鸠坑＞龙井43。

Effects of High Temperature Stress and Recovery on Photosynthesis and Stress Tolerance of Tea Leaves

In order to study the effect of high temperature stress on the photosynthesis rate, fluorescence characteristics, antioxidant enzyme activities and cell injury rates of Camellia sinensis in south region of the Yangtze River, four varieties of tea trees such as Fuding dabaicha, Jiukeng, Longjing 43 and Wuniuzao were investigated under different high temperature stress（35℃ and 40℃,with 25℃ as control）in artificial climate box for 6,12,18,24,48 hours, then recovered for 9 days. The results showed that high temperature stress inhibited the maximum net photosynthetic rate of tea and maximal photochemical efficiency (Fv/Fm) significantly, the maximum net photosynthetic rate and Fv/Fm declined faster when the processing was longer and the temperature was higher. In addition to Fuding dabaicha under 35℃, other varieties of tea could not be recovered to the normal level during a recovery. The SOD activities of Camellia sinensis leaves rose rapidly at the first 12 hours, and then decreased. The average of MDA contents achieved maximum when the temperature were conducted for 48 hours, the leaf cell injury rates increased with high temperature and processing time. The order of the heat resistance among four Camellia sinensis was Fuding dabaicha＞Wuniuza＞Jiukeng＞Longjing 43. The study provided a basis for scientific research of Camellia sinensis.