|Title||Temperature response of bundle-sheath conductance in maize leaves|
|Author(s)||Yin, Xinyou; Putten, Peter E.L. Van Der; Struik, Paul C.; Driever, Steven M.|
|Source||Journal of Experimental Botany 67 (2016)9. - ISSN 0022-0957 - p. 2699 - 2714.|
Centre for Crop Systems Analysis
|Publication type||Refereed Article in a scientific journal|
|Keyword(s)||Diffusive resistance - maximum PEPc activity - maximum Rubisco activity - modelling - warming effect - Zea mays|
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.