Protocol to study the photosynthetic response of maize to the CO2-temperature coupling effect at ear stage using a specialized designed gradient

Global warming will change the photosynthesis and transpiration of plants greatly and ultimately affect water use efficiency (WUE). Here, we present a protocol to investigate the response of maize WUE to the coupling effect of CO2 and temperature at ear stage using a specialized designed gradient. We describe steps for plant culture, parameter measurements, model fitting, and statistical analysis. This protocol holds potential for studying the response of WUE and CO2 adaptation across various plant species. For complete details on the use and execution of this protocol, please refer to Sun et al.1