title: Effects of light intensity on cyclic electron flow around PSI and its relationship to non-photochemical quenching of Chl fluorescence in tobacco leaves.
abstract: We tested the hypothesis that plants grown under high light intensity (HL-plants) had a large activity of cyclic electron flow around PSI (CEF-PSI) compared with plants grown under low light (LL-plants). To evaluate the activity of CEF-PSI, the relationships between photosynthesis rate, quantum yields of both PSII and PSI, and Chl fluorescence parameters were analyzed simultaneously in intact leaves of tobacco plants which had been grown under different light intensities (150 and 1,100 micromol photons m(-2) s(-1), respectively) and with different amounts of nutrients supplied. HL-plants showed a larger value of non-photochemical quenching (NPQ) of Chl fluorescence at the limited activity of photosynthetic linear electron flow. Furthermore, HL-plants had a larger activity of CEF-PSI than LL-plants. These results suggested that HL-plants dissipated the excess photon energy through NPQ by enhancing the ability of CEF-PSI to induce acidification of the thylakoid lumen.
authors.affiliation: Research Institute of Innovative Technology for the Earth (RITE), Kizu-cho, Soraku-gun, Kyoto, Japan. cmiyake@rite.or.jp
authors.forename: Chikahiro
authors.initials: C
authors.lastname: Miyake
authors.forename: Sayaka
authors.initials: S
authors.lastname: Horiguchi
authors.forename: Amane
authors.initials: A
authors.lastname: Makino
authors.forename: Yuki
authors.initials: Y
authors.lastname: Shinzaki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Tomizawa
mesh_terms: D002734:Chlorophyll / Q000378:metabolism*; D004583:Electrons; D005453:Fluorescence; D008027:Light; D010777:Photochemistry; D045331:Photosystem I Protein Complex / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism / Q000528:radiation effects; D014026:Nicotiana / Q000378:metabolism / Q000528:radiation effects*
chemical_list: D045331:Photosystem I Protein Complex; D002734:Chlorophyll