Effects of actinic light intensity on photosynthetic characteristics of Arabidopsis thaliana with knockout of alpha-carbonic anhydrase 2 gene

In the Arabidopsis thaliana plants with knock-out of alpha-carbonic anhydrase 2 gene grown under 80 μmol quanta m-2 s-1 the ratio of chlorophyll a to chlorophyll b and the non-photochemical quenching of chlorophyll a fluorescence were higher, while the effective quantum yield and the amount of starch in leaves were lower as compared with wild type plants. After transfer of both plants to increased light intensity, 400 μmol quanta m-2 s-1 for 14 days the first characteristics increased in much lesser extent in mutant plants than in wild type plants, and became less than in wild type plants. There against, under these conditions the effective quantum yield and the amount of starch became higher in the mutant plants. The data are discussed as the result of the alpha-CA2 involvement into a control of proton concentration in the thylakoid lumen.