干旱对苹果属植物叶绿素荧光参数的影响

目的]研究干旱对苹果属植物砧木荧光参数的影响。方法]以1年生抗旱能力较强的八棱海棠和抗旱性较弱的平邑甜茶实生幼苗为试验材料,采用营养液水培法培养幼苗,用20%聚乙二醇(PEG6000)模拟干旱胁迫,对这2种幼苗根系进行处理。结果]在干旱胁迫下,2个苹果属植物品种叶绿素荧光动力学曲线发生了明显变化,随着干旱胁迫时间的延长,八棱海棠和平邑甜茶的Yield、ETR、Fv/Fm、qP均下降,且随着水分胁迫的加强,降低越明显,F0上升,qN先上升后下降,但八棱海棠F0上升幅度比平邑甜茶小,而qN上升幅度比平邑甜茶大,说明八棱海棠PSⅡ抵御干旱的能力比平邑甜茶强。结论]干旱胁迫不仅直接引发苹果属植物光合结构的变化,而且也影响光合电子的传递。

Effects of Drought on Chlorophyll Fluorescence Parameters of Malus Plant

Objective] The propose was to study on the effects of drought on chlorophyll fluorescence parameters of Malus plant.Method] With one-year-old seedlings of Malus micromalus Rehd with stronger drought resistance and Malus hupehensis pamp Reld with weaker drought resistance as tested materials,they were cultured by nutrient solution hydroponics method and their roots were treated by 20% polythyene glycol(PEG6000) that could simulate drought stress.Result] Under drought stress,the dynamical curve of chlorophyll fluorescence in 2 varieties of Malus plant showed an obvious change.The quantum yield of PSⅡ linear electron(Yield),the electron transport rate(ETR),original light energy transforming rate(Fv/Fm),and photochemical quenching coefficient(qP) of M.micromalus and M.hupehensis pamp were decreased with prolonging of drought stress time.While Minimal fluorescence(F0) was risen and non-photochemical quenching coefficient(qN) was first increased and then decreased with the strengthening of drought stress.The rising extent of Fo in M.micromalus was smaller then that in M.hupehensis pamp,while the rising extent of qN in the farmer was greater then that in later,showing that the ability of PSⅡ resisting drought in M.micromalus was stronger than that in M.hupehensis pamp.Conclusion] Drought stress not only caused the change of photosynthetic structure in Malus plant directly,but also affect the transformation of photosynthetic electron.