小麦叶片PSI光抑制对光合电子传递链的影响

梁英, 李玉婷, 车兴凯, 李月楠, 罗蛟, 张珂豪, 张子山*, 赵世杰*
山东农业大学生命科学学院, 作物生物学国家重点实验室, 山东泰安271018

通信作者:张子山;E-mail: zhangzishantaian@163.com, sjzhao@sdau.edu.cn

摘 要:

强光等逆境下光系统活性的下降被称为光抑制。高等植物中光系统I (PSI)和光系统II (PSII)都会发生光抑制。目前PSII光抑制对PSI的影响已被广泛研究, 而PSI光抑制对PSII的影响研究较少, 这主要是因为没有专一性诱导PSI光抑制的方法。有研究报道, 常温频闪光可以较为专一地伤害PSI。本研究发现持续光处理3 h和频闪光处理4 h小麦叶片PSII最大光化学效率(Fv/Fm)降低的幅度相同。当PSII光抑制相同时, 频闪光处理叶片的PSII实际光化学效率[Y(II)]和非光化学淬灭(NPQ)都明显低于持续光处理叶片, 而且只有频闪光处理叶片发生了PSI光抑制。因为两种光处理导致PSII光抑制程度相同, 所以叶片光合机构活性的差异主要是由PSI光抑制引起的。PSI光抑制不仅限制PSII向下游的电子传递, 而且会使PSII最重要的光保护机制NPQ失活。此外, 本研究还发现持续光处理下Y(II)下降是由PSII反应中心伤害导致的, 而频闪光处理下Y(II)降低主要是由PSII反应中心关闭造成的。因此, 本研究表明: PSI光抑制会抑制PSII电子向下游的传递, 并且抑制NPQ活性, 从而加重PSII光抑制。

关键词:小麦; 频闪光; PSI光抑制; 实际光化学效率; NPQ

收稿:2018-05-28   修定:2018-09-11

资助:国家自然科学基金(31701966、31771691、31871544)、山东省自主创新重大关键技术计划(2014GJJS0201-1)和中国博士后科学基金(146459)。

Effect of PSI photoinhibition on photosynthetic electron transport chain in wheat (Triticum aestivum) leaves

LIANG Ying, LI Yu-Ting, CHE Xing-Kai, LI Yue-Nan, LUO Jiao, ZHANG Ke-Hao, ZHANG Zi-Shan*, ZHAO Shi-Jie*
State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, China

Corresponding author: ZHANG Zi-Shan; E-mail: zhangzishantaian@163.com, sjzhao@sdau.edu.cn

Abstract:

The decline in activity of photosystems under stress conditions such as high light is known as photoinhibition. Photoinhibition occurs in both photosystem I (PSI) and photosystem II (PSII) in higher plants. At present, the effect of PSII photoinhibition on PSI has been extensively studied, but the effect of PSI photoinhibition on PSII is still unknown. This is mainly due to the lack of the method for specifically inducing PSI photoinhibition. Recent studies have found that repetitive short-pulse light (rSP) can specifically hurt PSI under normal temperature. In this study, the decrease of PSII maximum photochemical efficiency (Fv/Fm) was similar in the continuous light treatment for 3 h and the rSP treatment for 4 h. When the PSII photoinhibition was similar, the PSII actual photochemical efficiency [Y(II)] and non-photochemical quenching (NPQ) in the rSP treated leaves were significantly lower than those in leaves treated by continuous light, and only PSI photoinhibition was observed in the rSP-treated leaf. Since the two treatments resulted in the similar PSII photoinhibition, the differences in photosynthetic apparatus activity in leaves were mainly caused by PSI photoinhibition. PSI photoinhibition not only limited the electron transport of PSII downstream, but also inactivated NPQ, the most important photoprotective mechanism of PSII. In addition, the study also found that the decrease of Y(II) in continuous light treated leaves was caused by damage of PSII reaction center, and the decrease of Y(II) in rSP treated leaves was mainly caused by the close of PSII reaction center. Therefore, this study shows that PSI photoinhibition inhibits the downstream transport of PSII electrons and inhibits NPQ activity, thereby aggravating PSII photoinhibition.

Key words: wheat (Triticum aestivum); repetitive short-pulse light (rSP); PSI photoinhibition; actual photochemical efficiency; NPQ

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