Rice full-length cDNA over-expressed Arabidopsis mutant database
Research Contents
Photosynthesis (chlorophyll fluorescence)

Increasing plant production and productivity is a central topic in plant biology as a response to global warming and a way to meet food and energy needs. In photosynthesis, light energy is converted to chemical energy through electron transport, resulting in the formation of ATP and NADPH. CO2 is absorbed and incorporated into organic molecules. Therefore, photosynthesis is one of the most important determinants of plant productivity and CO2 removal. We used the chlorophyll fluorescence screening method to identify photosynthesis-related genes of rice. Chlorophyll fluorescence has been widely used to identify photosynthesis mutants because it reflects the state of photosynthetic electron transport. We used chlorophyll fluorescence imaging to isolate photosynthesis-related mutants. Arabidopsis plants were grown on MS agar plates without sucrose for 8-10 days under long-day conditions (80-100 µmol photons m-2 s-1). Each plate contained 4 FOX T2 lines, each with 16 seedlings. Chlorophyll fluorescence was measured during continuous illumination (350 µmol photons m-2 s-1, 2 min) with a chlorophyll fluorescence monitoring system (FluorCam 700MF, Photon Systems Instruments, Brno, Czech Republic). We captured chlorophyll fluorescence images every 2.5 s for 2 min with a CCD camera. We isolated lines that showed different chlorophyll fluorescence kinetics, as shown in the figure (blue lines).

Photosynthesis (high light stress)

Light is critical for the growth and development of photosynthetic organisms. However, too much light leads to photooxidative damage. Under high light, limited availability of electron acceptors, especially CO2, results in excess reduction of the photosynthetic electron transport chain. As over-reduction of electron carriers can increase the rate of production of reactive oxygen species, plants adjust to changes in the intensity of light to optimize photosynthesis and growth. Although the response of the photosynthetic apparatus to high irradiance must have an underlying regulatory mechanism, little is known about the mechanism. To understand it, we isolated high-light-tolerant mutants from FOX lines. Arabidopsis plants were grown on MS agar plates without sucrose for 8-10 days under long-day conditions (80-100 µmol photons m-2 s-1). Each plate contained 4 FOX lines, each with 16 seedlings. To isolate mutants defective in high-light response, we exposed plants to high light stress (1000 µmol photons m-2 s-1, 1 h), then measured chlorophyll fluorescence with a chlorophyll fluorescence monitoring system (FluorCam 700MF, Photon Systems Instruments, Brno, Czech Republic). We used the photosynthetic parameter Fv/Fm as an indicator of photooxidative damage. The maximum quantum yield of PSII (Fv/Fm) was calculated as (Fm - Fo)/Fm. We isolated mutants that showed higher Fv/Fm, as shown in the figure. Figure shows the image of Fv/Fm of 4 independent FOX lines. The color scale ranges from blue (low values of Fv/Fm) to red (high values of Fv/Fm).


Website policy Contact

Copyright © 2008