title: Photosynthetic induction and its diffusional, carboxylation and electron transport processes as affected by CO2 partial pressure, temperature, air humidity and blue irradiance.
abstract: Plants depend on photosynthesis for growth. In nature, factors such as temperature, humidity, CO2partial pressure, and spectrum and intensity of irradiance often fluctuate. Whereas irradiance intensity is most influential and has been studied in detail, understanding of interactions with other factors is lacking.
  
  
  
  We tested how photosynthetic induction after dark-light transitions was affected by CO2partial pressure (20, 40, 80 Pa), leaf temperatures (15·5, 22·8, 30·5 °C), leaf-to-air vapour pressure deficits (VPDleaf-air; 0·5, 0·8, 1·6, 2·3 kPa) and blue irradiance (0-20 %) in tomato leaves (Solanum lycopersicum).
  
  
  
  Rates of photosynthetic induction strongly increased with CO2partial pressure, due to increased apparent Rubisco activation rates and reduced diffusional limitations. High leaf temperature produced slightly higher induction rates, and increased intrinsic water use efficiency and diffusional limitation. High VPDleaf-airslowed down induction rates and apparent Rubisco activation and (at 2·3 kPa) induced damped stomatal oscillations. Blue irradiance had no effect. Slower apparent Rubisco activation in elevated VPDleaf-airmay be explained by low leaf internal CO2partial pressure at the beginning of induction.
  
  
  
  The environmental factors CO2partial pressure, temperature and VPDleaf-airhad significant impacts on rates of photosynthetic induction, as well as on underlying diffusional, carboxylation and electron transport processes. Furthermore, maximizing Rubisco activation rates would increase photosynthesis by at most 6-8 % in ambient CO2partial pressure (across temperatures and humidities), while maximizing rates of stomatal opening would increase photosynthesis by at most 1-3 %.
authors.affiliation: Horticulture and Product Physiology Group, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, the Netherlands elias.kaiser@wur.nl.
authors.forename: Elias
authors.initials: E
authors.lastname: Kaiser
authors.affiliation: Institute for Genomic Biology, University of Illinois, 1206 West Gregory Drive, Urbana, IL, USA.
authors.forename: Johannes
authors.initials: J
authors.lastname: Kromdijk
authors.affiliation: Horticulture and Product Physiology Group, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, the Netherlands.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Harbinson
authors.affiliation: Horticulture and Product Physiology Group, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, the Netherlands.
authors.forename: Ep
authors.initials: E
authors.lastname: Heuvelink
authors.affiliation: Horticulture and Product Physiology Group, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, the Netherlands.
authors.forename: Leo F M
authors.initials: LF
authors.lastname: Marcelis
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D004579:Electron Transport / Q000502:physiology*; D006813:Humidity; D008027:Light; D018551:Solanum lycopersicum / Q000378:metabolism / Q000502:physiology; D010313:Partial Pressure; D010788:Photosynthesis / Q000502:physiology*; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism; D013696:Temperature
chemical_list: D002734:Chlorophyll; D002245:Carbon Dioxide; D012273:Ribulose-Bisphosphate Carboxylase
keywords: CO2 concentration; Dynamic photosynthesis; Rubisco; Solanum lycopersicum; diffusional limitation; humidity; stomatal conductance; temperature; tomato