Study on Photosynthetic and Chlorophyll Fluorescence Characteristics of Transgenic Tobacco with AcCBF1 Gene

【Objective】 To explore the effects of AcCBF1 gene on photosynthesis, and provide a scientific basis for breeding new varieties of almonds. 【Method】 In this experiment, the transgenic tobacco with AcCBF1 gene was obtained by Agrobacterium-mediated method. After a week of continuous outdoor high temperature weather at 37 ℃, the diural variation characteristics of photosynthetic parameters and chlorophyll fluorescence parameters were measured and analyzed with the wild tobacco as control. 【Result】 In this experiment, three transgenic tobaccos were successfully obtained by Agrobacterium-mediated method, and PCR analysis showed that the AcCBF1 gene had been stably integrated into the tobacco genome. Both Pn and Gs of transgenic tobacco and wild tobacco showed a "double peak" curve and peaks appeared at the same time. The first peak appeared at 12:00, The phenomenon of "mid-day depression" occurred at 16:00, and the second peak appeared at 18:00. The daily average values of Pn were 6.496 and 4.553 μ mol/(m²·s), respectively ; the daily average values of Gs were 157.357 and 133.371 μ mol/(m²·s) , respectively. The Fo of transgenic tobacco and wild tobacco showed a trend of increasing first and then decreasing, and Fm showed a trend of decreasing first and then increasing. The daily variation trends of Fv/Fm, Fv/Fo, and ΦPSII were the same, and they all showed a trend of decreasing first and then increasing. The daily average values of Fv/Fm values were 0.821 and 0.736, respectively. The daily average values of Fv/Fo were 5.044 and 3.391, respectively. The daily average values of ΦPSII were 0.763 and 0.600, respectively. 【Conclusion】 By analyzing and comparing the changes of photosynthetic parameters and fluorescence chlorophyll parameters, we found that transgenic AcCBF1 tobacco has higher assimilation capacity of CO₂, stronger photosynthetic ability, more stable photosynthetic reaction center and stronger adaptability to high temperature comparing with wild tobacco. To cope with drought and high temperature in summer, we could select and breed new almond varieties with AcCBF1 high-expression.