Abstract
In photosynthesis of higher plants, electrons are transported from photosystem II to photosystem I and finally to NADP+. The electron transport is couple to the proton translocation across the thylakoid membrane. Resulting trans-thylakoid proton gradient contributes to formation of the proton motive force to drive ATP synthesis. In this study, isolation of Arabidopsis thaliana mutants having defects in the photosynthetic electron transport was attempted. Especially, we focused on mutants impaired in the alternative electron transport, e.g. the cyclic electron flow around photosystem I and the Meher-preoxidase reaction. Using chlorophyll fluorescence in low oxygen (2%), we selected 37 mutants from ca. 30,000 F2 plants derived by EMS mutagenesis. In a plant showing severe phenotype in chlorophyll fluorescence, a mutation was found in the gene for fructose-1,6-bisphosphate aldolase (AT4g38970). In this plant, electron donation from the stromal reductants to the intersystem electron carriers was accelerated.
