Moderate photoinhibition of photosystem II protects photosystem I from photodamage at chilling stress in tobacco leaves

Frontiers in Plant Science

Ying-Jie eYang¹  Wei eHuang¹  Shi-Bao eZhang¹  Hong eHu¹ 

[1] Chinese Academy of Sciences;

关键词: Photoprotection;    Electron Transfer;    photosystem I;    photosystem II;    Chilling Temperature;    growth light intensity;   

DOI  :  10.3389/fpls.2016.00182

来源: DOAJ

【 摘 要 】

It has been indicated that photosystem I (PSI) is susceptible to chilling-light stress in tobacco leaves, but the effect of growth light intensity on chilling-induced PSI photoinhibition in tobacco is unclear. We examined the effects of chilling temperature (4°C) associated with moderate light intensity (300 μmol photons m−2 s−1) on the activities of PSI and photosystem II (PSII) in leaves from sun- and shade-grown plants of tobacco (Nicotiana tabacum cv. k326). The sun leaves had a higher activity of alternative electron flow than the shade leaves. After 4 h chilling treatment, the sun leaves showed significantly a higher PSI photoinhibition than the shade leaves. At chilling temperature the sun leaves showed a greater electron flow from PSII to PSI, accompanying with a lower P700 oxidation ratio. When leaves were pre-treated with lincomycin, PSII activity decreased by 42% (sun leaves) and 47% (shade leaves) after 2 h exposure to the chilling-light stress, but PSI activity remained stable during the chilling-light treatment, because the electron flow from PSII to PSI was remarkably depressed. These results indicated that the stronger chilling-induced PSI photoinhibition in the sun leaves was resulted from a greater electron flow from PSII to PSI. Furthermore, moderate PSII photoinhibition depressed electron flow to PSI and then protected PSI activity against further photodamage in chilled tobacco leaves.

【 授权许可】

Unknown