高丹草叶片PSⅡ光化学活性的抗旱优势  

The heterosis of photosystem Ⅱ functions in Sorghum bicolor×S.sudanense seedlings under drought stress

作　　者：胡举伟[1] 张会慧[1,2] 张秀丽[1] 逄好胜 孙广玉[1] 

机构地区：[1]东北林业大学生命科学学院,黑龙江哈尔滨150040 [2]黑龙江省科学院自然与生态研究所,黑龙江哈尔滨150040

出　　处：《草业科学》2015年第3期392-399,共8页Pratacultural Science

基　　金：中央高校基本科研业务费专项资金项目(2572015AA27);哈尔滨市科技创新人才研究专项(2013RFXXJ063);黑龙江省自然科学基金重点项目(ZD2011-05)

摘　　要：本试验利用快速叶绿素荧光诱导动力学分析技术研究了高丹草(Sorghum bicolor×S.sudanense)和苏丹草(S.sudanense)叶片PSⅡ光化学活性对干旱的响应。结果表明,随着干旱的加剧,高丹草和苏丹草幼苗叶片PSⅡ的最大光化学效率(Fv/Fm)和效能指数(PIABS)明显降低,特别是PIABS的降低幅度明显大于Fv/Fm,即干旱下两种牧草幼苗叶片的PSⅡ光化学活性降低,但不同干旱程度下高丹草幼苗叶片的PSⅡ光化学活性明显高于苏丹草。分析原因可以发现:干旱下高丹草幼苗叶片OJIP曲线上0.15和0.3 ms时(L点和K点)的相对可变荧光VL和VK增加幅度明显小于苏丹草,即干旱条件下对高丹草幼苗叶片PSⅡ电子供体侧放氧复合体OCE活性和类囊体聚合状态的影响明显小于苏丹草,这对于电子传递链上的电子供应及电子传递的稳定性起到了重要的作用。另外,干旱下两种牧草幼苗叶片OJIP曲线上2和30 ms时(J点和I点)的相对可变荧光VJ和VI明显增加,即干旱导致PSⅡ光化学活性降低还与PSⅡ电子受体侧电子由QA向QB传递受阻以及PQ库接受电子能力的降低有关。但干旱下高丹草和苏丹草幼苗叶片仅VJ差异明显,而VI却无明显差异,这说明干旱下高丹草幼苗叶片电子传递体QB接受电子的能力明显高于苏丹草,从而使干旱下高丹草幼苗叶片PSⅡ受体侧电子传递能力高于苏丹草。The response of photosystem Ⅱ activity in leaves of Sorghum sudanense and S.bicolor × S.sudanense to drought stress was investigated by the fast chlorophyll fluorescence induction dynamics analysis.The results showed that the maximum photochemical efficiency( Fv/ Fm) and the performance of PSⅡ activity( PIABS) in these two species decreased with the increasing intensity of drought stress,especially the PIABSreduction was significantly greater than Fv/ Fm.Although the PSⅡ photochemical activity in leaves of both of these two species seedlings decreased under drought stress,the PSⅡ photochemical activity in S.bicolor × S.sudanense seedling leaves was significantly higher( P < 0.05) than that in S.sudanense seedling.The possible reasons for these difference included that the rates of relative variable fluorescence increase at 0.15 and 0.3 ms on the OJIP curve of S.bicolor ×S.sudanense seedlings were significantly less than that of S.sudanense seedlings under drought stress and that the impacts of drought on the complex activities of electron donor side OCE oxygen and thylakoid aggregation state in S.bicolor × S.sudanense seedlings was significantly less than those in S.sudanense seedlings which was important for the supply,transport and stability of electron in electron transport chain.In addition,the relative variable fluorescence of VJand VIat 2 and 30 ms on the OJIP curve( J point and I point) of these two species forage seedlings significantly increased under drought stress suggested that the decrease of PSⅡ photochemical activity was correlated with the block of QAto QBtransport in PSⅡ electron acceptor side and the decrease of the PQ library capability of accepting electron.However,there was significant difference between VJand no significant difference between VIof S.bicolor × S.sudanense and S.sudanense leaves,indicating that the electron transfer body QBability to accept electrons and the ability of transmitting electron of PSⅡ donor side of S.bicolor × S.sudanense seedlings were higher

关 键 词：高丹草 杂交种 干旱 PSⅡ 

分 类 号：Q945[生物学—植物学]