Regulation of Leaf Angle Protects Photosystem I under Fluctuating Light in Tobacco Young Leaves

Cells

Xiao-Qian Wang¹  Shi-Bao Zhang¹  Hu Sun¹  Zhi-Lan Zeng¹  Wei Huang¹ 

[1] Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China;

关键词: leaf angle;    fluctuating light;    photosynthesis;    photoinhibition;    photoprotection;    photosystem I;   

DOI  :  10.3390/cells11020252

来源: DOAJ

【 摘 要 】

Fluctuating light is a typical light condition in nature and can cause selective photodamage to photosystem I (PSI). The sensitivity of PSI to fluctuating light is influenced by the amplitude of low/high light intensity. Tobacco mature leaves are tended to be horizontal to maximize the light absorption and photosynthesis, but young leaves are usually vertical to diminish the light absorption. Therefore, we tested the hypothesis that such regulation of the leaf angle in young leaves might protect PSI against photoinhibition under fluctuating light. We found that, upon a sudden increase in illumination, PSI was over-reduced in extreme young leaves but was oxidized in mature leaves. After fluctuating light treatment, such PSI over-reduction aggravated PSI photoinhibition in young leaves. Furthermore, the leaf angle was tightly correlated to the extent of PSI photoinhibition induced by fluctuating light. Therefore, vertical young leaves are more susceptible to PSI photoinhibition than horizontal mature leaves when exposed to the same fluctuating light. In young leaves, the vertical leaf angle decreased the light absorption and thus lowered the amplitude of low/high light intensity. Therefore, the regulation of the leaf angle was found for the first time as an important strategy used by young leaves to protect PSI against photoinhibition under fluctuating light. To our knowledge, we show here new insight into the photoprotection for PSI under fluctuating light in nature.

【 授权许可】

Unknown