Related Experiment Video
Updated: Jun 19, 2026

Evaluation of Photosynthetic Behaviors by Simultaneous Measurements of Leaf Reflectance and Chlorophyll Fluorescence Analyses
Published on: August 9, 2019
Cyclic electron flow around photosystem I is required for adaptation to high temperature in a subtropical forest
Song-heng Jin1, Xue-qin Li, Jun-yan Hu
1School of Forestry and Biotechnology, Zhejiang Forestry University, Lin'an 311300, China.
Abstract:
Dissipation mechanisms of excess photon energy under high-temperature stress were studied in a subtropical forest tree seedling, Ficus concinna. Net CO(2) assimilation rate decreased to 16% of the control after 20 d high-temperature stress, and thus the absorption of photon energy exceeded the energy required for CO(2) assimilation. The efficiency of excitation energy capture by open photosystem II (PSII) reaction centres (F(v)'/F(m)') at moderate irradiance, photochemical quenching (q(P)), and the quantum yield of PSII electron transport (Phi(PSII)) were significantly lower after high-temperature stress. Nevertheless, non-photochemical quenching (q(NP)) and energy-dependent quenching (q(E)) were significantly higher under such conditions. The post-irradiation transient of chlorophyll (Chl) fluorescence significantly increased after the turnoff of the actinic light (AL), and this increase was considerably higher in the 39 degrees C-grown seedlings than in the 30 degrees C-grown ones. The increased post-irradiation fluorescence points to enhanced cyclic electron transport around PSI under high growth temperature conditions, thus helping to dissipate excess photon energy non-radiatively.
More Related Videos
06:04Assessing Structural Traits in Triticum aestivum and Zea mays for C3 and C4 Photosynthetic Differentiation Using Free-hand and Semi-thin Sections
Published on: July 12, 2024
08:40Separation of Spinach Thylakoid Protein Complexes by Native Green Gel Electrophoresis and Band Characterization using Time-Correlated Single Photon Counting
Published on: February 14, 2019
Related Concept Videos
The Calvin Benson Cycle
The Z-Scheme of Electron Transport in Photosynthesis
Photosystem I
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...
C4 Pathway and CAM
C4 Pathway
The C4 pathway is used by plants such as...
Photosystem II
The pigment molecules are arranged across two photosystem domains — the antenna complex and the reaction center. The main aim of the pigment molecules...
The Calvin Cycle