Photosynthetic regulation under fluctuating light in field-grown Cerasus cerasoides: A comparison of young and mature leaves

Publication date: Available online 29 August 2019Source: Biochimica et Biophysica Acta (BBA) - BioenergeticsAuthor(s): Ying-Jie Yang, Shi-Bao Zhang, Ji-Hua Wang, Wei HuangAbstractPhotosystem I (PSI) is a potential target of photoinhibition under fluctuating light. However, photosynthetic regulation under fluctuating light in field-grown plants is little known. Furthermore, it is unclear how young leaves protect PSI against fluctuating light under natural field conditions. In the present study, we examined chlorophyll fluorescence, P700 redox state and the electrochromic shift signal in the young and mature leaves of field-grown Cerasus cerasoides (Rosaceae). Within the first seconds after any increase in light intensity, young leaves showed higher proton gradient (ΔpH) across the thylakoid membranes than the mature leaves, preventing over-reduction of PSI in the young leaves. As a result, PSI was more tolerant to fluctuating light in the young leaves than in the mature leaves. Interestingly, after transition from low to high light, the activity of cyclic electron flow (CEF) in young leaves increased first to a high level and then decreased to a stable value, while this rapid stimulation of CEF was not observed in the mature leaves. Furthermore, the over-reduction of PSI significantly stimulated CEF in the young leaves but not in the mature leaves. Taken together, within the first seconds after any increase in illumination, the stimulation of CEF favors the rapid lumen acidif...

Source: Biochimica et Biophysica Acta (BBA) Bioenergetics - August 30, 2019 Category: Biochemistry Source Type: research