Photosynthetic responses of switchgrass to light and CO 2 under different precipitation treatments

作者：Christina Kieffer, Navneet Kaur, Jianwei Li, Roser Matamala, Philip A. Fay, Dafeng Hui · 发表于：GCB Bioenergy · 年份：2024 · DOI：10.1111/gcbb.13138 · 被引用次数：6 · 研究领域：Bioenergy crop production and management、Plant Water Relations and Carbon Dynamics、Plant responses to elevated CO2

Abstract Switchgrass ( Panicum virgatum L.) is a prominent bioenergy crop with robust resilience to environmental stresses. However, our knowledge regarding how precipitation changes affect switchgrass photosynthesis and its responses to light and CO 2 remains limited. To address this knowledge gap, we conducted a field precipitation experiment with five different treatments, including −50%, −33%, 0%, +33%, and +50% of ambient precipitation. To determine the responses of leaf photosynthesis to CO 2 concentration and light, we measured leaf net photosynthesis of switchgrass under different CO 2 concentrations and light levels in 2020 and 2021 for each of the five precipitation treatments. We first evaluated four light and CO 2 response models (i.e., rectangular hyperbola model, nonrectangular hyperbola model, exponential model, and the modified rectangular hyperbola model) using the measurements in the ambient precipitation treatment. Based on the fitting criteria, we selected the nonrectangular hyperbola model as the optimal model and applied it to all precipitation treatments, and estimated model parameters. Overall, the model fit field measurements well for the light and CO 2 response curves. Precipitation change did not influence the maximum net photosynthetic rate ( P max ) but influenced other model parameters including quantum yield ( α ), convexity ( θ ), dark respiration ( R d ), light compensation point ( LCP ), and saturated light point ( LSP ). Specifically, the me...