Affiliation:
1. National Engineering and Technology Center for Information Agriculture, Engineering Research Center of Smart Agriculture, Ministry of Education, Key Laboratory for Crop System Analysis and Decision Making, Ministry of Agriculture, Jiangsu Key Laboratory for Information Agriculture, Jiangsu Collaborative Innovation Center for Modern Crop Production, College of Agriculture Nanjing Agricultural University Nanjing Jiangsu China
2. Key Laboratory of Specialty Agri‐product Quality and Hazard Controlling Technology of Zhejiang Province, College of Life Sciences China Jiliang University Hangzhou Zhejiang China
Abstract
AbstractIn response to increasing global warming, extreme heat stress significantly alters photosynthetic production. While numerous studies have investigated the temperature effects on photosynthesis, factors like vapour pressure deficit (VPD), leaf nitrogen, and feedback of sink limitation during and after extreme heat stress remain underexplored. This study assessed photosynthesis calculations in seven rice growth models using observed maximum photosynthetic rate (Pmax) during and after short‐term extreme heat stress in multi‐year environment‐controlled experiments. Biochemical models (FvCB‐type) outperformed light response curve‐based models (LRC‐type) when incorporating observed leaf nitrogen, photosynthetically active radiation, temperatures, and intercellular CO2 concentration (Ci) as inputs. Prediction uncertainty during heat stress treatment primarily resulted from variation in temperatures and Ci. Improving FVPD (the slope for the linear effect of VPD on Ci/Ca) to be temperature‐dependent, rather than constant as in original models, significantly improved Ci prediction accuracy under heat stress. Leaf nitrogen response functions led to model variation in leaf photosynthesis predictions after heat stress, which was mitigated by calibrated nitrogen response functions based on active photosynthetic nitrogen. Additionally, accounting for observed differences in carbohydrate accumulation between panicles and stems during grain filling improved the feedback of sink limitation, reducing Ci overestimation under heat stress treatments.