title: Temperature response of bundle-sheath conductance in maize leaves.
abstract: A small bundle-sheath conductance (g bs) is essential for the C4 CO2-concentrating mechanism to suppress photorespiration effectively. To predict the productivity of C4 crops accurately under global warming, it is necessary to examine whether and how g bs responds to temperature. We investigated the temperature response of g bs in maize by fitting a C4 photosynthesis model to combined gas exchange and chlorophyll fluorescence measurements of irradiance and CO2 response curves at 21% and 2% O2 within the range of 13.5-39 °C. The analysis was based on reported kinetic constants of C4 Rubisco and phosphoenolpyruvate carboxylase and temperature responses of C3 mesophyll conductance (g m). The estimates of g bs varied greatly with leaf temperature. The temperature response of g bs was well described by the peaked Arrhenius equation, with the optimum temperature being ~34 °C. The assumed temperature responses of g m had only a slight impact on the temperature response of g bs In contrast, using extreme values of some enzyme kinetic constants changed the shape of the response, from the peaked optimum response to the non-peaked Arrhenius pattern. Further studies are needed to confirm such an Arrhenius response pattern from independent measurement techniques and to assess whether it is common across C4 species.
authors.affiliation: Centre for Crop Systems Analysis, Department of Plant Sciences, Wageningen University, PO Box 430, 6700 AK Wageningen, The Netherlands Xinyou.Yin@wur.nl.
authors.forename: Xinyou
authors.initials: X
authors.lastname: Yin
authors.affiliation: Centre for Crop Systems Analysis, Department of Plant Sciences, Wageningen University, PO Box 430, 6700 AK Wageningen, The Netherlands.
authors.forename: Peter E L
authors.initials: PE
authors.lastname: van der Putten
authors.affiliation: Centre for Crop Systems Analysis, Department of Plant Sciences, Wageningen University, PO Box 430, 6700 AK Wageningen, The Netherlands.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Driever
authors.affiliation: Centre for Crop Systems Analysis, Department of Plant Sciences, Wageningen University, PO Box 430, 6700 AK Wageningen, The Netherlands.
authors.forename: Paul C
authors.initials: PC
authors.lastname: Struik
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism; D019069:Cell Respiration / Q000502:physiology; D010788:Photosynthesis / Q000502:physiology; D018515:Plant Leaves / Q000166:cytology / Q000502:physiology*; D013696:Temperature; D003313:Zea mays / Q000502:physiology*
chemical_list: D002245:Carbon Dioxide
keywords: Diffusive resistance; Zea mays.; maximum PEPc activity; maximum Rubisco activity; modelling; warming effect