title: Metabolic and diffusional limitations of photosynthesis in fluctuating irradiance in Arabidopsis thaliana.
abstract: A better understanding of the metabolic and diffusional limitations of photosynthesis in fluctuating irradiance can help identify targets for improving crop yields. We used different genotypes of Arabidopsis thaliana to characterise the importance of Rubisco activase (Rca), stomatal conductance (gs), non-photochemical quenching of chlorophyll fluorescence (NPQ) and sucrose phosphate synthase (SPS) on photosynthesis in fluctuating irradiance. Leaf gas exchange and chlorophyll fluorescence were measured in leaves exposed to stepwise increases and decreases in irradiance. rwt43, which has a constitutively active Rubisco enzyme in different irradiance intensities (except in darkness), showed faster increases than the wildtype, Colombia-0, in photosynthesis rates after step increases in irradiance. rca-2, having decreased Rca concentration, showed lower rates of increase. In aba2-1, high gs increased the rate of change after stepwise irradiance increases, while in C24, low gs tended to decrease it. Differences in rates of change between Colombia-0 and plants with low levels of NPQ (npq1-2, npq4-1) or SPS (spsa1) were negligible. In Colombia-0, the regulation of Rubisco activation and of gs were therefore limiting for photosynthesis in fluctuating irradiance, while levels of NPQ or SPS were not. This suggests Rca and gs as targets for improvement of photosynthesis of plants in fluctuating irradiance.
authors: Horticulture and Product Physiology Group, Department of Plant Sciences, Wageningen University, PO Box 16, 6700 AA Wageningen, The Netherlands.
authors: Elias
authors: E
authors: Kaiser
authors: Centre for Crop Systems Analysis, Department of Plant Sciences, Wageningen University, PO Box 430, 6700 AK Wageningen, The Netherlands.
authors: Alejandro
authors: A
authors: Morales
authors: Horticulture and Product Physiology Group, Department of Plant Sciences, Wageningen University, PO Box 16, 6700 AA Wageningen, The Netherlands.
authors: Jeremy
authors: J
authors: Harbinson
authors: Horticulture and Product Physiology Group, Department of Plant Sciences, Wageningen University, PO Box 16, 6700 AA Wageningen, The Netherlands.
authors: Ep
authors: E
authors: Heuvelink
authors: Horticulture and Product Physiology Group, Department of Plant Sciences, Wageningen University, PO Box 16, 6700 AA Wageningen, The Netherlands.|Laboratory of Genetics, Department of Plant Sciences, Wageningen University, PO Box 16, 6700 AA Wageningen, The Netherlands.
authors: Aina E
authors: AE
authors: Prinzenberg
authors: Horticulture and Product Physiology Group, Department of Plant Sciences, Wageningen University, PO Box 16, 6700 AA Wageningen, The Netherlands.
authors: Leo F M
authors: LF
authors: Marcelis
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects*; D029681:Arabidopsis Proteins / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D005838:Genotype; D005964:Glucosyltransferases; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000378:metabolism; D009154:Mutation; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism* / Q000528:radiation effects; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D045342:Light-Harvesting Protein Complexes; D045332:Photosystem II Protein Complex; D002734:Chlorophyll; D002245:Carbon Dioxide; D005964:Glucosyltransferases; C022698:sucrose-phosphate synthase; D012273:Ribulose-Bisphosphate Carboxylase