渍害胁迫及其恢复对油菜幼苗叶片PSⅡ光化学特性的影响

Effects of Waterlogging Stress and Recovery Process on PSⅡ Photochemical Characteristics of Rape at Seedling Stage

以中乐油2号和蓉油11号油菜为材料,通过盆栽试验,研究渍害胁迫及恢复进程中油菜幼苗叶片光系统Ⅱ(PSⅡ)光化学特性的变化.结果表明:随着渍害胁迫的加剧,两品种油菜叶片初始荧光(F0)、非光化学淬灭系数(qN)不断上升,最大荧光(Fm)、PSⅡ最大光化学量子产量(Fv/Fm)、PSⅡ实际光化学量子产量(Yield)、表观光合电子传递速率(ETR)、光化学淬灭系数(qP)不断下降,说明随着渍害胁迫的加剧,PSⅡ部分反应中心受到破坏,光合电子传递受阻,光能转换效率下降,发生明显光抑制;从第13d起进行恢复处理,所有叶绿素荧光参数均有所恢复,但仍未达到对照水平.可见,当渍害胁迫超出了油菜机体自我调节的阈值时,油菜叶片的部分光合机构发生不可逆的破坏,最终影响油菜的正常生长.

With zhongleyou -2 and rongyou - 11 of main rapes as test objects, a pot experiment was conducted to study on PS Ⅱ photochemical characteristics of rapes at seedling stage under waterlogging stress and recovery process. The result showed that minimum chlorophyll florescence （F0） and coefficient of non - photochemical quenching （qN） increased with waterlogging stress exacerbating, maximum chlorophyll florescence （Fin）, the maxi- mal quantum yield of PS Ⅱ （Fv/Fm）, quantum yield of PS Ⅱ photochemistry（Yield）, estimated electron transport rate （ETR） and coefficient of photochemical quenching （qP） had declined. This shows that the partial response center of PS Ⅱ was destructed, and photosynthetic electron transport was obstructed, and the conversion efficiency of light energy declined. It resulted in an obvious photoinhibition. Recovery processed from the 13th day,with F0 and qN declining slightly, Fm, Fv/Fm, Yield, ETR and qP increasing slightly, but all not recovering to control level. This showed that the partial photosynthetic organ had got the irreversible destruction. In the,, end the normal growth of rape had been affected, and waterlogging stress had exceeded the self - adjusting threshold of the ripe body.