小白菊内酯及降温速率对含水生菜种子抗冷性的影响

以生菜Lactuca sativa含水种子为试材，通过添加外源动物泛素E3连接酶激活剂小白菊内酯(Parthenolide)，及不同降温速率的程序降温处理，研究Parthenolide对程序降温过程中生菜种子抗冷性的影响。结果表明，无论在快速(60 ℃·h-1)还是慢速(3 ℃·h-1)降温过程中，添加Parthenolide都会抑制生菜种子对低温的耐受性，而且发芽率明显比对照组低，这种降低程度在降温至-20 ℃时最为明显，说明在程序降温过程中，泛素化调控通路参与种子对冷冻的响应。通过实时定量荧光PCR对泛素化相关基因和ICE1基因的表达分析表明，Parthenolide抑制了慢速降温过程中环指型E3连接酶COP1和抗冻因子ICE1的mRNA表达水平。Parthenolide对SOD活性的影响进一步证明其影响种子在程序降温过程中的耐冻性机制。

Effects of Parthenolide and Decending Speed of Temperature on Chilling Resistance of Imbibed Seeds of Lactuca sativa

In order to study the effects of Parthenolide on chilling resistance of Lactuca sativa seeds during programmed cooling, the seeds were imbibed by exogenous animal ubiquitin E3 ligase activator Parthenolide before treated with programmed cooling with different cooling rates. The results showed that the addition of Parthenolide reduced the freezing tolerance of lettuce seeds in both fast and slow cooling treatments, and the germination rates after both cooling treatments were significantly lower than control, the effects of Parthenolide were the most obvious when the temperature was reduced to -20 ℃, which indicating that during the programmed cooling, the ubiquitination regulatory pathway did participate in the resistance to freezing in seeds. The expression of ubiquitination-related genes and ICE1 gene were detected by real-time quantitative PCR. It was found that Parthenolide inhibited the expression of RING-finger E3 ligase COP1 and anti-freezing factor ICE1 during the slow cooling. The effects of Parthenolide on the activities of SOD were further proved that during the programmed cooling process, Parthenolide may destroy the freezing resistance system of lettuce seeds.