【摘要】 为探究低温强光对移栽期烤烟幼苗不同生长阶段叶片的胁迫机制,利用人工模拟移栽期低温强光环境的方法,研究了由温室弱光环境转移到低温高光环境下烤烟幼苗新生叶和成熟叶的快相叶绿素荧光动力学曲线的变化情况。结果表明:烤烟幼苗新生叶的光合性能指数PIABS显著低于成熟叶,而PSⅡ最大光合效率Fv/Fm值虽低于成熟叶,但差异不显著;在低温高光下新生叶片Fv/Fm和PIABS的降低幅度也明显低于成熟叶,说明在低温强光下新生叶更容易发生光抑制现象。新生叶J点和I点的相对可变荧光(V_J和V_I)均明显高于成熟叶,即新生叶PSⅡ受体侧的电子传递速率明显低于成熟叶,且在低温高光下新生叶的V_J增加幅度大于成熟叶,即低温强光加剧了新生叶PSⅡ受体侧电子由QA向QB传递的抑制程度,但新生叶的V_I增加幅度却较成熟叶小,说明低温强光对烤烟幼苗新生叶QB向PQ的电子传递影响较小。新生叶的K点和L点的相对可变荧光(V_K和V_L)明显高于成熟叶,并且低温高光处理下新生叶V_K和V_L的增加幅度明显大于成熟叶,说明低温高光处理对新生叶放氧复合体和类囊体膜结构的伤害程度更大。总之,移栽期低温强光胁迫对烤烟幼苗新生叶PSⅡ功能的伤害程度明显大于成熟叶,这与新生叶光化学活性、电子传递速率以及OEC对低温强光胁迫更为敏感有关。更多还原

【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(PIABS) 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 PIABSof 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(VJand 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 VJwere significantly greater than mature leaves,the inhibition of electrons transfer from QAto QB in PSⅡreceptor under high light and low temperature. V_Iincreased amplitude of young leaves were relatively smaller than mature leaves under high light and low temperature,which indicated that the effects of electrons transferfrom QBto PQ in young leaves were fewer under high light and low temperature,the electron transfer blocked sites in young leaves were still QAto QBtransfer process. The relative variable fluorescence(V_Kand V_L) of young leaves were significantly higher than that of mature leaves,under high light and low temperature,the values of V_Kand 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.更多还原