Abstract: In order to reveal mechanism of internal injury on leaves under transplanting stage for flue-cured tobacco seedling. The changes of chlorophyll fluorescence kinetics curve of young and mature leaves were studied under high light and low temperature environment transferred from the weak light and mildness greenhouse through the methods of artificial simulation.The results showed that photosynthetic performance index (PI_ABS) in young leaves was lower significantly than that of mature leaves and the maximum photochemical efficiency of PS Ⅱ (Fv/Fm) was lower than that of mature leaves, but the difference between them was not significant.Especially, under the environment of high light and low temperature, the parameters of Fv/Fm and PI_ABS of young leaves reduction were significantly higher than the mature leaves, which indicated that young leaves were more likely to occuring inhibition phenomenon under high light and low temperature. The relative variable fluorescence (V_J and V_I) in young leaves were significantly higher than that of mature leaves, which suggested that electron transfer rate in PS Ⅱ receptor side of young leaves were significantly lower than the mature leaves. Under high lights and low-temperature, the increasing extend of V_J were significantly greater than mature leaves, the inhibition of electrons transfer from Q_A to Q_B in PS Ⅱreceptor under high light and low temperature.V_I increased amplitude of young leaves were relatively smaller than mature leaves under high light and low temperature, which indicated that the effects of electrons transfer from Q_B to PQ in young leaves were fewer under high light and low temperature, the electron transfer blocked sites in young leaves were still Q_A to Q_B transfer process. The relative variable fluorescence (V_K and V_L) of young leaves were significantly higher than that of mature leaves, under high light and low temperature, the values of V_K and V_L of young leaves raise were significantly higher than the mature leaves, which indicated that damaged degree in young leaves were more serious than mature leaves, which showed that high light and low temperature led to more damaged for oxygen evolving complex and thylakoid membrane structure in young leaves. Conclusion, damaged degree of young leaves PS Ⅱ function under high light and low temperature stress in transplanting stage were bigger than the mature leaf, which were relevant with photochemical activity, electron transfer rate and OEC in young seedlings leaves were sensitive to high light and low temperature.

Key words: Flue-cured tobacco, Chlorophyll fluorescence kinetics, Low temperature and high light, PS Ⅱ

CLC Number: 

• S572.01